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f7728002c1
Commit780bc7903a
("virtio_ring: Support DMA APIs") makes virtqueue_add() return -EIO when we fail to map our I/O buffers. This is a very realistic scenario for guests with encrypted memory, as swiotlb may run out of space, depending on it's size and the I/O load. The virtio-blk driver interprets -EIO form virtqueue_add() as an IO error, despite the fact that swiotlb full is in absence of bugs a recoverable condition. Let us change the return code to -ENOMEM, and make the block layer recover form these failures when virtio-blk encounters the condition described above. Cc: stable@vger.kernel.org Fixes:780bc7903a
("virtio_ring: Support DMA APIs") Signed-off-by: Halil Pasic <pasic@linux.ibm.com> Tested-by: Michael Mueller <mimu@linux.ibm.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2330 lines
60 KiB
C
2330 lines
60 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/* Virtio ring implementation.
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*
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* Copyright 2007 Rusty Russell IBM Corporation
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*/
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#include <linux/virtio.h>
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#include <linux/virtio_ring.h>
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#include <linux/virtio_config.h>
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#include <linux/device.h>
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#include <linux/slab.h>
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#include <linux/module.h>
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#include <linux/hrtimer.h>
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#include <linux/dma-mapping.h>
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#include <xen/xen.h>
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#ifdef DEBUG
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/* For development, we want to crash whenever the ring is screwed. */
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#define BAD_RING(_vq, fmt, args...) \
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do { \
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dev_err(&(_vq)->vq.vdev->dev, \
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"%s:"fmt, (_vq)->vq.name, ##args); \
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BUG(); \
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} while (0)
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/* Caller is supposed to guarantee no reentry. */
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#define START_USE(_vq) \
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do { \
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if ((_vq)->in_use) \
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panic("%s:in_use = %i\n", \
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(_vq)->vq.name, (_vq)->in_use); \
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(_vq)->in_use = __LINE__; \
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} while (0)
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#define END_USE(_vq) \
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do { BUG_ON(!(_vq)->in_use); (_vq)->in_use = 0; } while(0)
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#define LAST_ADD_TIME_UPDATE(_vq) \
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do { \
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ktime_t now = ktime_get(); \
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\
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/* No kick or get, with .1 second between? Warn. */ \
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if ((_vq)->last_add_time_valid) \
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WARN_ON(ktime_to_ms(ktime_sub(now, \
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(_vq)->last_add_time)) > 100); \
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(_vq)->last_add_time = now; \
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(_vq)->last_add_time_valid = true; \
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} while (0)
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#define LAST_ADD_TIME_CHECK(_vq) \
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do { \
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if ((_vq)->last_add_time_valid) { \
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WARN_ON(ktime_to_ms(ktime_sub(ktime_get(), \
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(_vq)->last_add_time)) > 100); \
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} \
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} while (0)
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#define LAST_ADD_TIME_INVALID(_vq) \
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((_vq)->last_add_time_valid = false)
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#else
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#define BAD_RING(_vq, fmt, args...) \
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do { \
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dev_err(&_vq->vq.vdev->dev, \
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"%s:"fmt, (_vq)->vq.name, ##args); \
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(_vq)->broken = true; \
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} while (0)
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#define START_USE(vq)
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#define END_USE(vq)
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#define LAST_ADD_TIME_UPDATE(vq)
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#define LAST_ADD_TIME_CHECK(vq)
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#define LAST_ADD_TIME_INVALID(vq)
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#endif
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struct vring_desc_state_split {
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void *data; /* Data for callback. */
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struct vring_desc *indir_desc; /* Indirect descriptor, if any. */
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};
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struct vring_desc_state_packed {
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void *data; /* Data for callback. */
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struct vring_packed_desc *indir_desc; /* Indirect descriptor, if any. */
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u16 num; /* Descriptor list length. */
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u16 next; /* The next desc state in a list. */
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u16 last; /* The last desc state in a list. */
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};
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struct vring_desc_extra_packed {
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dma_addr_t addr; /* Buffer DMA addr. */
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u32 len; /* Buffer length. */
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u16 flags; /* Descriptor flags. */
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};
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struct vring_virtqueue {
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struct virtqueue vq;
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/* Is this a packed ring? */
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bool packed_ring;
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/* Is DMA API used? */
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bool use_dma_api;
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/* Can we use weak barriers? */
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bool weak_barriers;
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/* Other side has made a mess, don't try any more. */
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bool broken;
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/* Host supports indirect buffers */
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bool indirect;
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/* Host publishes avail event idx */
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bool event;
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/* Head of free buffer list. */
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unsigned int free_head;
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/* Number we've added since last sync. */
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unsigned int num_added;
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/* Last used index we've seen. */
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u16 last_used_idx;
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union {
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/* Available for split ring */
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struct {
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/* Actual memory layout for this queue. */
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struct vring vring;
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/* Last written value to avail->flags */
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u16 avail_flags_shadow;
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/*
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* Last written value to avail->idx in
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* guest byte order.
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*/
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u16 avail_idx_shadow;
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/* Per-descriptor state. */
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struct vring_desc_state_split *desc_state;
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/* DMA address and size information */
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dma_addr_t queue_dma_addr;
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size_t queue_size_in_bytes;
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} split;
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/* Available for packed ring */
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struct {
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/* Actual memory layout for this queue. */
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struct {
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unsigned int num;
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struct vring_packed_desc *desc;
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struct vring_packed_desc_event *driver;
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struct vring_packed_desc_event *device;
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} vring;
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/* Driver ring wrap counter. */
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bool avail_wrap_counter;
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/* Device ring wrap counter. */
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bool used_wrap_counter;
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/* Avail used flags. */
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u16 avail_used_flags;
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/* Index of the next avail descriptor. */
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u16 next_avail_idx;
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/*
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* Last written value to driver->flags in
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* guest byte order.
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*/
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u16 event_flags_shadow;
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/* Per-descriptor state. */
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struct vring_desc_state_packed *desc_state;
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struct vring_desc_extra_packed *desc_extra;
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/* DMA address and size information */
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dma_addr_t ring_dma_addr;
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dma_addr_t driver_event_dma_addr;
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dma_addr_t device_event_dma_addr;
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size_t ring_size_in_bytes;
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size_t event_size_in_bytes;
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} packed;
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};
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/* How to notify other side. FIXME: commonalize hcalls! */
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bool (*notify)(struct virtqueue *vq);
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/* DMA, allocation, and size information */
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bool we_own_ring;
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#ifdef DEBUG
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/* They're supposed to lock for us. */
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unsigned int in_use;
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/* Figure out if their kicks are too delayed. */
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bool last_add_time_valid;
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ktime_t last_add_time;
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#endif
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};
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/*
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* Helpers.
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*/
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#define to_vvq(_vq) container_of(_vq, struct vring_virtqueue, vq)
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static inline bool virtqueue_use_indirect(struct virtqueue *_vq,
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unsigned int total_sg)
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{
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struct vring_virtqueue *vq = to_vvq(_vq);
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/*
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* If the host supports indirect descriptor tables, and we have multiple
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* buffers, then go indirect. FIXME: tune this threshold
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*/
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return (vq->indirect && total_sg > 1 && vq->vq.num_free);
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}
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/*
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* Modern virtio devices have feature bits to specify whether they need a
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* quirk and bypass the IOMMU. If not there, just use the DMA API.
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*
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* If there, the interaction between virtio and DMA API is messy.
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*
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* On most systems with virtio, physical addresses match bus addresses,
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* and it doesn't particularly matter whether we use the DMA API.
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*
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* On some systems, including Xen and any system with a physical device
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* that speaks virtio behind a physical IOMMU, we must use the DMA API
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* for virtio DMA to work at all.
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*
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* On other systems, including SPARC and PPC64, virtio-pci devices are
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* enumerated as though they are behind an IOMMU, but the virtio host
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* ignores the IOMMU, so we must either pretend that the IOMMU isn't
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* there or somehow map everything as the identity.
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*
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* For the time being, we preserve historic behavior and bypass the DMA
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* API.
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*
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* TODO: install a per-device DMA ops structure that does the right thing
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* taking into account all the above quirks, and use the DMA API
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* unconditionally on data path.
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*/
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static bool vring_use_dma_api(struct virtio_device *vdev)
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{
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if (!virtio_has_iommu_quirk(vdev))
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return true;
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/* Otherwise, we are left to guess. */
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/*
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* In theory, it's possible to have a buggy QEMU-supposed
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* emulated Q35 IOMMU and Xen enabled at the same time. On
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* such a configuration, virtio has never worked and will
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* not work without an even larger kludge. Instead, enable
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* the DMA API if we're a Xen guest, which at least allows
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* all of the sensible Xen configurations to work correctly.
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*/
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if (xen_domain())
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return true;
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return false;
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}
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size_t virtio_max_dma_size(struct virtio_device *vdev)
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{
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size_t max_segment_size = SIZE_MAX;
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if (vring_use_dma_api(vdev))
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max_segment_size = dma_max_mapping_size(&vdev->dev);
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return max_segment_size;
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}
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EXPORT_SYMBOL_GPL(virtio_max_dma_size);
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static void *vring_alloc_queue(struct virtio_device *vdev, size_t size,
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dma_addr_t *dma_handle, gfp_t flag)
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{
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if (vring_use_dma_api(vdev)) {
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return dma_alloc_coherent(vdev->dev.parent, size,
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dma_handle, flag);
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} else {
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void *queue = alloc_pages_exact(PAGE_ALIGN(size), flag);
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if (queue) {
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phys_addr_t phys_addr = virt_to_phys(queue);
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*dma_handle = (dma_addr_t)phys_addr;
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/*
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* Sanity check: make sure we dind't truncate
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* the address. The only arches I can find that
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* have 64-bit phys_addr_t but 32-bit dma_addr_t
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* are certain non-highmem MIPS and x86
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* configurations, but these configurations
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* should never allocate physical pages above 32
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* bits, so this is fine. Just in case, throw a
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* warning and abort if we end up with an
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* unrepresentable address.
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*/
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if (WARN_ON_ONCE(*dma_handle != phys_addr)) {
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free_pages_exact(queue, PAGE_ALIGN(size));
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return NULL;
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}
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}
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return queue;
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}
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}
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static void vring_free_queue(struct virtio_device *vdev, size_t size,
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void *queue, dma_addr_t dma_handle)
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{
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if (vring_use_dma_api(vdev))
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dma_free_coherent(vdev->dev.parent, size, queue, dma_handle);
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else
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free_pages_exact(queue, PAGE_ALIGN(size));
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}
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/*
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* The DMA ops on various arches are rather gnarly right now, and
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* making all of the arch DMA ops work on the vring device itself
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* is a mess. For now, we use the parent device for DMA ops.
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*/
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static inline struct device *vring_dma_dev(const struct vring_virtqueue *vq)
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{
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return vq->vq.vdev->dev.parent;
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}
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/* Map one sg entry. */
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static dma_addr_t vring_map_one_sg(const struct vring_virtqueue *vq,
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struct scatterlist *sg,
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enum dma_data_direction direction)
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{
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if (!vq->use_dma_api)
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return (dma_addr_t)sg_phys(sg);
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/*
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* We can't use dma_map_sg, because we don't use scatterlists in
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* the way it expects (we don't guarantee that the scatterlist
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* will exist for the lifetime of the mapping).
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*/
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return dma_map_page(vring_dma_dev(vq),
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sg_page(sg), sg->offset, sg->length,
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direction);
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}
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static dma_addr_t vring_map_single(const struct vring_virtqueue *vq,
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void *cpu_addr, size_t size,
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enum dma_data_direction direction)
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{
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if (!vq->use_dma_api)
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return (dma_addr_t)virt_to_phys(cpu_addr);
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return dma_map_single(vring_dma_dev(vq),
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cpu_addr, size, direction);
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}
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static int vring_mapping_error(const struct vring_virtqueue *vq,
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dma_addr_t addr)
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{
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if (!vq->use_dma_api)
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return 0;
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return dma_mapping_error(vring_dma_dev(vq), addr);
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}
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/*
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* Split ring specific functions - *_split().
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*/
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static void vring_unmap_one_split(const struct vring_virtqueue *vq,
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struct vring_desc *desc)
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{
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u16 flags;
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if (!vq->use_dma_api)
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return;
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flags = virtio16_to_cpu(vq->vq.vdev, desc->flags);
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if (flags & VRING_DESC_F_INDIRECT) {
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dma_unmap_single(vring_dma_dev(vq),
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virtio64_to_cpu(vq->vq.vdev, desc->addr),
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virtio32_to_cpu(vq->vq.vdev, desc->len),
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(flags & VRING_DESC_F_WRITE) ?
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DMA_FROM_DEVICE : DMA_TO_DEVICE);
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} else {
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dma_unmap_page(vring_dma_dev(vq),
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virtio64_to_cpu(vq->vq.vdev, desc->addr),
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virtio32_to_cpu(vq->vq.vdev, desc->len),
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(flags & VRING_DESC_F_WRITE) ?
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DMA_FROM_DEVICE : DMA_TO_DEVICE);
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}
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}
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static struct vring_desc *alloc_indirect_split(struct virtqueue *_vq,
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unsigned int total_sg,
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gfp_t gfp)
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{
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struct vring_desc *desc;
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unsigned int i;
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/*
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* We require lowmem mappings for the descriptors because
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* otherwise virt_to_phys will give us bogus addresses in the
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* virtqueue.
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*/
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gfp &= ~__GFP_HIGHMEM;
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desc = kmalloc_array(total_sg, sizeof(struct vring_desc), gfp);
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if (!desc)
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return NULL;
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for (i = 0; i < total_sg; i++)
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desc[i].next = cpu_to_virtio16(_vq->vdev, i + 1);
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return desc;
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}
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static inline int virtqueue_add_split(struct virtqueue *_vq,
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struct scatterlist *sgs[],
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unsigned int total_sg,
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unsigned int out_sgs,
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unsigned int in_sgs,
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void *data,
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void *ctx,
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gfp_t gfp)
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{
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struct vring_virtqueue *vq = to_vvq(_vq);
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struct scatterlist *sg;
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struct vring_desc *desc;
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unsigned int i, n, avail, descs_used, uninitialized_var(prev), err_idx;
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int head;
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bool indirect;
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START_USE(vq);
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BUG_ON(data == NULL);
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BUG_ON(ctx && vq->indirect);
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if (unlikely(vq->broken)) {
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END_USE(vq);
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return -EIO;
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}
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LAST_ADD_TIME_UPDATE(vq);
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BUG_ON(total_sg == 0);
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head = vq->free_head;
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if (virtqueue_use_indirect(_vq, total_sg))
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desc = alloc_indirect_split(_vq, total_sg, gfp);
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else {
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desc = NULL;
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WARN_ON_ONCE(total_sg > vq->split.vring.num && !vq->indirect);
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}
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if (desc) {
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/* Use a single buffer which doesn't continue */
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indirect = true;
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/* Set up rest to use this indirect table. */
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i = 0;
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descs_used = 1;
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} else {
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indirect = false;
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desc = vq->split.vring.desc;
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i = head;
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descs_used = total_sg;
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}
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if (vq->vq.num_free < descs_used) {
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pr_debug("Can't add buf len %i - avail = %i\n",
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descs_used, vq->vq.num_free);
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/* FIXME: for historical reasons, we force a notify here if
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* there are outgoing parts to the buffer. Presumably the
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* host should service the ring ASAP. */
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if (out_sgs)
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vq->notify(&vq->vq);
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if (indirect)
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kfree(desc);
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END_USE(vq);
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return -ENOSPC;
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}
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for (n = 0; n < out_sgs; n++) {
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for (sg = sgs[n]; sg; sg = sg_next(sg)) {
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dma_addr_t addr = vring_map_one_sg(vq, sg, DMA_TO_DEVICE);
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if (vring_mapping_error(vq, addr))
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goto unmap_release;
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desc[i].flags = cpu_to_virtio16(_vq->vdev, VRING_DESC_F_NEXT);
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desc[i].addr = cpu_to_virtio64(_vq->vdev, addr);
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desc[i].len = cpu_to_virtio32(_vq->vdev, sg->length);
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prev = i;
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i = virtio16_to_cpu(_vq->vdev, desc[i].next);
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}
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}
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for (; n < (out_sgs + in_sgs); n++) {
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for (sg = sgs[n]; sg; sg = sg_next(sg)) {
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dma_addr_t addr = vring_map_one_sg(vq, sg, DMA_FROM_DEVICE);
|
|
if (vring_mapping_error(vq, addr))
|
|
goto unmap_release;
|
|
|
|
desc[i].flags = cpu_to_virtio16(_vq->vdev, VRING_DESC_F_NEXT | VRING_DESC_F_WRITE);
|
|
desc[i].addr = cpu_to_virtio64(_vq->vdev, addr);
|
|
desc[i].len = cpu_to_virtio32(_vq->vdev, sg->length);
|
|
prev = i;
|
|
i = virtio16_to_cpu(_vq->vdev, desc[i].next);
|
|
}
|
|
}
|
|
/* Last one doesn't continue. */
|
|
desc[prev].flags &= cpu_to_virtio16(_vq->vdev, ~VRING_DESC_F_NEXT);
|
|
|
|
if (indirect) {
|
|
/* Now that the indirect table is filled in, map it. */
|
|
dma_addr_t addr = vring_map_single(
|
|
vq, desc, total_sg * sizeof(struct vring_desc),
|
|
DMA_TO_DEVICE);
|
|
if (vring_mapping_error(vq, addr))
|
|
goto unmap_release;
|
|
|
|
vq->split.vring.desc[head].flags = cpu_to_virtio16(_vq->vdev,
|
|
VRING_DESC_F_INDIRECT);
|
|
vq->split.vring.desc[head].addr = cpu_to_virtio64(_vq->vdev,
|
|
addr);
|
|
|
|
vq->split.vring.desc[head].len = cpu_to_virtio32(_vq->vdev,
|
|
total_sg * sizeof(struct vring_desc));
|
|
}
|
|
|
|
/* We're using some buffers from the free list. */
|
|
vq->vq.num_free -= descs_used;
|
|
|
|
/* Update free pointer */
|
|
if (indirect)
|
|
vq->free_head = virtio16_to_cpu(_vq->vdev,
|
|
vq->split.vring.desc[head].next);
|
|
else
|
|
vq->free_head = i;
|
|
|
|
/* Store token and indirect buffer state. */
|
|
vq->split.desc_state[head].data = data;
|
|
if (indirect)
|
|
vq->split.desc_state[head].indir_desc = desc;
|
|
else
|
|
vq->split.desc_state[head].indir_desc = ctx;
|
|
|
|
/* Put entry in available array (but don't update avail->idx until they
|
|
* do sync). */
|
|
avail = vq->split.avail_idx_shadow & (vq->split.vring.num - 1);
|
|
vq->split.vring.avail->ring[avail] = cpu_to_virtio16(_vq->vdev, head);
|
|
|
|
/* Descriptors and available array need to be set before we expose the
|
|
* new available array entries. */
|
|
virtio_wmb(vq->weak_barriers);
|
|
vq->split.avail_idx_shadow++;
|
|
vq->split.vring.avail->idx = cpu_to_virtio16(_vq->vdev,
|
|
vq->split.avail_idx_shadow);
|
|
vq->num_added++;
|
|
|
|
pr_debug("Added buffer head %i to %p\n", head, vq);
|
|
END_USE(vq);
|
|
|
|
/* This is very unlikely, but theoretically possible. Kick
|
|
* just in case. */
|
|
if (unlikely(vq->num_added == (1 << 16) - 1))
|
|
virtqueue_kick(_vq);
|
|
|
|
return 0;
|
|
|
|
unmap_release:
|
|
err_idx = i;
|
|
|
|
if (indirect)
|
|
i = 0;
|
|
else
|
|
i = head;
|
|
|
|
for (n = 0; n < total_sg; n++) {
|
|
if (i == err_idx)
|
|
break;
|
|
vring_unmap_one_split(vq, &desc[i]);
|
|
i = virtio16_to_cpu(_vq->vdev, desc[i].next);
|
|
}
|
|
|
|
if (indirect)
|
|
kfree(desc);
|
|
|
|
END_USE(vq);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
static bool virtqueue_kick_prepare_split(struct virtqueue *_vq)
|
|
{
|
|
struct vring_virtqueue *vq = to_vvq(_vq);
|
|
u16 new, old;
|
|
bool needs_kick;
|
|
|
|
START_USE(vq);
|
|
/* We need to expose available array entries before checking avail
|
|
* event. */
|
|
virtio_mb(vq->weak_barriers);
|
|
|
|
old = vq->split.avail_idx_shadow - vq->num_added;
|
|
new = vq->split.avail_idx_shadow;
|
|
vq->num_added = 0;
|
|
|
|
LAST_ADD_TIME_CHECK(vq);
|
|
LAST_ADD_TIME_INVALID(vq);
|
|
|
|
if (vq->event) {
|
|
needs_kick = vring_need_event(virtio16_to_cpu(_vq->vdev,
|
|
vring_avail_event(&vq->split.vring)),
|
|
new, old);
|
|
} else {
|
|
needs_kick = !(vq->split.vring.used->flags &
|
|
cpu_to_virtio16(_vq->vdev,
|
|
VRING_USED_F_NO_NOTIFY));
|
|
}
|
|
END_USE(vq);
|
|
return needs_kick;
|
|
}
|
|
|
|
static void detach_buf_split(struct vring_virtqueue *vq, unsigned int head,
|
|
void **ctx)
|
|
{
|
|
unsigned int i, j;
|
|
__virtio16 nextflag = cpu_to_virtio16(vq->vq.vdev, VRING_DESC_F_NEXT);
|
|
|
|
/* Clear data ptr. */
|
|
vq->split.desc_state[head].data = NULL;
|
|
|
|
/* Put back on free list: unmap first-level descriptors and find end */
|
|
i = head;
|
|
|
|
while (vq->split.vring.desc[i].flags & nextflag) {
|
|
vring_unmap_one_split(vq, &vq->split.vring.desc[i]);
|
|
i = virtio16_to_cpu(vq->vq.vdev, vq->split.vring.desc[i].next);
|
|
vq->vq.num_free++;
|
|
}
|
|
|
|
vring_unmap_one_split(vq, &vq->split.vring.desc[i]);
|
|
vq->split.vring.desc[i].next = cpu_to_virtio16(vq->vq.vdev,
|
|
vq->free_head);
|
|
vq->free_head = head;
|
|
|
|
/* Plus final descriptor */
|
|
vq->vq.num_free++;
|
|
|
|
if (vq->indirect) {
|
|
struct vring_desc *indir_desc =
|
|
vq->split.desc_state[head].indir_desc;
|
|
u32 len;
|
|
|
|
/* Free the indirect table, if any, now that it's unmapped. */
|
|
if (!indir_desc)
|
|
return;
|
|
|
|
len = virtio32_to_cpu(vq->vq.vdev,
|
|
vq->split.vring.desc[head].len);
|
|
|
|
BUG_ON(!(vq->split.vring.desc[head].flags &
|
|
cpu_to_virtio16(vq->vq.vdev, VRING_DESC_F_INDIRECT)));
|
|
BUG_ON(len == 0 || len % sizeof(struct vring_desc));
|
|
|
|
for (j = 0; j < len / sizeof(struct vring_desc); j++)
|
|
vring_unmap_one_split(vq, &indir_desc[j]);
|
|
|
|
kfree(indir_desc);
|
|
vq->split.desc_state[head].indir_desc = NULL;
|
|
} else if (ctx) {
|
|
*ctx = vq->split.desc_state[head].indir_desc;
|
|
}
|
|
}
|
|
|
|
static inline bool more_used_split(const struct vring_virtqueue *vq)
|
|
{
|
|
return vq->last_used_idx != virtio16_to_cpu(vq->vq.vdev,
|
|
vq->split.vring.used->idx);
|
|
}
|
|
|
|
static void *virtqueue_get_buf_ctx_split(struct virtqueue *_vq,
|
|
unsigned int *len,
|
|
void **ctx)
|
|
{
|
|
struct vring_virtqueue *vq = to_vvq(_vq);
|
|
void *ret;
|
|
unsigned int i;
|
|
u16 last_used;
|
|
|
|
START_USE(vq);
|
|
|
|
if (unlikely(vq->broken)) {
|
|
END_USE(vq);
|
|
return NULL;
|
|
}
|
|
|
|
if (!more_used_split(vq)) {
|
|
pr_debug("No more buffers in queue\n");
|
|
END_USE(vq);
|
|
return NULL;
|
|
}
|
|
|
|
/* Only get used array entries after they have been exposed by host. */
|
|
virtio_rmb(vq->weak_barriers);
|
|
|
|
last_used = (vq->last_used_idx & (vq->split.vring.num - 1));
|
|
i = virtio32_to_cpu(_vq->vdev,
|
|
vq->split.vring.used->ring[last_used].id);
|
|
*len = virtio32_to_cpu(_vq->vdev,
|
|
vq->split.vring.used->ring[last_used].len);
|
|
|
|
if (unlikely(i >= vq->split.vring.num)) {
|
|
BAD_RING(vq, "id %u out of range\n", i);
|
|
return NULL;
|
|
}
|
|
if (unlikely(!vq->split.desc_state[i].data)) {
|
|
BAD_RING(vq, "id %u is not a head!\n", i);
|
|
return NULL;
|
|
}
|
|
|
|
/* detach_buf_split clears data, so grab it now. */
|
|
ret = vq->split.desc_state[i].data;
|
|
detach_buf_split(vq, i, ctx);
|
|
vq->last_used_idx++;
|
|
/* If we expect an interrupt for the next entry, tell host
|
|
* by writing event index and flush out the write before
|
|
* the read in the next get_buf call. */
|
|
if (!(vq->split.avail_flags_shadow & VRING_AVAIL_F_NO_INTERRUPT))
|
|
virtio_store_mb(vq->weak_barriers,
|
|
&vring_used_event(&vq->split.vring),
|
|
cpu_to_virtio16(_vq->vdev, vq->last_used_idx));
|
|
|
|
LAST_ADD_TIME_INVALID(vq);
|
|
|
|
END_USE(vq);
|
|
return ret;
|
|
}
|
|
|
|
static void virtqueue_disable_cb_split(struct virtqueue *_vq)
|
|
{
|
|
struct vring_virtqueue *vq = to_vvq(_vq);
|
|
|
|
if (!(vq->split.avail_flags_shadow & VRING_AVAIL_F_NO_INTERRUPT)) {
|
|
vq->split.avail_flags_shadow |= VRING_AVAIL_F_NO_INTERRUPT;
|
|
if (!vq->event)
|
|
vq->split.vring.avail->flags =
|
|
cpu_to_virtio16(_vq->vdev,
|
|
vq->split.avail_flags_shadow);
|
|
}
|
|
}
|
|
|
|
static unsigned virtqueue_enable_cb_prepare_split(struct virtqueue *_vq)
|
|
{
|
|
struct vring_virtqueue *vq = to_vvq(_vq);
|
|
u16 last_used_idx;
|
|
|
|
START_USE(vq);
|
|
|
|
/* We optimistically turn back on interrupts, then check if there was
|
|
* more to do. */
|
|
/* Depending on the VIRTIO_RING_F_EVENT_IDX feature, we need to
|
|
* either clear the flags bit or point the event index at the next
|
|
* entry. Always do both to keep code simple. */
|
|
if (vq->split.avail_flags_shadow & VRING_AVAIL_F_NO_INTERRUPT) {
|
|
vq->split.avail_flags_shadow &= ~VRING_AVAIL_F_NO_INTERRUPT;
|
|
if (!vq->event)
|
|
vq->split.vring.avail->flags =
|
|
cpu_to_virtio16(_vq->vdev,
|
|
vq->split.avail_flags_shadow);
|
|
}
|
|
vring_used_event(&vq->split.vring) = cpu_to_virtio16(_vq->vdev,
|
|
last_used_idx = vq->last_used_idx);
|
|
END_USE(vq);
|
|
return last_used_idx;
|
|
}
|
|
|
|
static bool virtqueue_poll_split(struct virtqueue *_vq, unsigned last_used_idx)
|
|
{
|
|
struct vring_virtqueue *vq = to_vvq(_vq);
|
|
|
|
return (u16)last_used_idx != virtio16_to_cpu(_vq->vdev,
|
|
vq->split.vring.used->idx);
|
|
}
|
|
|
|
static bool virtqueue_enable_cb_delayed_split(struct virtqueue *_vq)
|
|
{
|
|
struct vring_virtqueue *vq = to_vvq(_vq);
|
|
u16 bufs;
|
|
|
|
START_USE(vq);
|
|
|
|
/* We optimistically turn back on interrupts, then check if there was
|
|
* more to do. */
|
|
/* Depending on the VIRTIO_RING_F_USED_EVENT_IDX feature, we need to
|
|
* either clear the flags bit or point the event index at the next
|
|
* entry. Always update the event index to keep code simple. */
|
|
if (vq->split.avail_flags_shadow & VRING_AVAIL_F_NO_INTERRUPT) {
|
|
vq->split.avail_flags_shadow &= ~VRING_AVAIL_F_NO_INTERRUPT;
|
|
if (!vq->event)
|
|
vq->split.vring.avail->flags =
|
|
cpu_to_virtio16(_vq->vdev,
|
|
vq->split.avail_flags_shadow);
|
|
}
|
|
/* TODO: tune this threshold */
|
|
bufs = (u16)(vq->split.avail_idx_shadow - vq->last_used_idx) * 3 / 4;
|
|
|
|
virtio_store_mb(vq->weak_barriers,
|
|
&vring_used_event(&vq->split.vring),
|
|
cpu_to_virtio16(_vq->vdev, vq->last_used_idx + bufs));
|
|
|
|
if (unlikely((u16)(virtio16_to_cpu(_vq->vdev, vq->split.vring.used->idx)
|
|
- vq->last_used_idx) > bufs)) {
|
|
END_USE(vq);
|
|
return false;
|
|
}
|
|
|
|
END_USE(vq);
|
|
return true;
|
|
}
|
|
|
|
static void *virtqueue_detach_unused_buf_split(struct virtqueue *_vq)
|
|
{
|
|
struct vring_virtqueue *vq = to_vvq(_vq);
|
|
unsigned int i;
|
|
void *buf;
|
|
|
|
START_USE(vq);
|
|
|
|
for (i = 0; i < vq->split.vring.num; i++) {
|
|
if (!vq->split.desc_state[i].data)
|
|
continue;
|
|
/* detach_buf_split clears data, so grab it now. */
|
|
buf = vq->split.desc_state[i].data;
|
|
detach_buf_split(vq, i, NULL);
|
|
vq->split.avail_idx_shadow--;
|
|
vq->split.vring.avail->idx = cpu_to_virtio16(_vq->vdev,
|
|
vq->split.avail_idx_shadow);
|
|
END_USE(vq);
|
|
return buf;
|
|
}
|
|
/* That should have freed everything. */
|
|
BUG_ON(vq->vq.num_free != vq->split.vring.num);
|
|
|
|
END_USE(vq);
|
|
return NULL;
|
|
}
|
|
|
|
static struct virtqueue *vring_create_virtqueue_split(
|
|
unsigned int index,
|
|
unsigned int num,
|
|
unsigned int vring_align,
|
|
struct virtio_device *vdev,
|
|
bool weak_barriers,
|
|
bool may_reduce_num,
|
|
bool context,
|
|
bool (*notify)(struct virtqueue *),
|
|
void (*callback)(struct virtqueue *),
|
|
const char *name)
|
|
{
|
|
struct virtqueue *vq;
|
|
void *queue = NULL;
|
|
dma_addr_t dma_addr;
|
|
size_t queue_size_in_bytes;
|
|
struct vring vring;
|
|
|
|
/* We assume num is a power of 2. */
|
|
if (num & (num - 1)) {
|
|
dev_warn(&vdev->dev, "Bad virtqueue length %u\n", num);
|
|
return NULL;
|
|
}
|
|
|
|
/* TODO: allocate each queue chunk individually */
|
|
for (; num && vring_size(num, vring_align) > PAGE_SIZE; num /= 2) {
|
|
queue = vring_alloc_queue(vdev, vring_size(num, vring_align),
|
|
&dma_addr,
|
|
GFP_KERNEL|__GFP_NOWARN|__GFP_ZERO);
|
|
if (queue)
|
|
break;
|
|
if (!may_reduce_num)
|
|
return NULL;
|
|
}
|
|
|
|
if (!num)
|
|
return NULL;
|
|
|
|
if (!queue) {
|
|
/* Try to get a single page. You are my only hope! */
|
|
queue = vring_alloc_queue(vdev, vring_size(num, vring_align),
|
|
&dma_addr, GFP_KERNEL|__GFP_ZERO);
|
|
}
|
|
if (!queue)
|
|
return NULL;
|
|
|
|
queue_size_in_bytes = vring_size(num, vring_align);
|
|
vring_init(&vring, num, queue, vring_align);
|
|
|
|
vq = __vring_new_virtqueue(index, vring, vdev, weak_barriers, context,
|
|
notify, callback, name);
|
|
if (!vq) {
|
|
vring_free_queue(vdev, queue_size_in_bytes, queue,
|
|
dma_addr);
|
|
return NULL;
|
|
}
|
|
|
|
to_vvq(vq)->split.queue_dma_addr = dma_addr;
|
|
to_vvq(vq)->split.queue_size_in_bytes = queue_size_in_bytes;
|
|
to_vvq(vq)->we_own_ring = true;
|
|
|
|
return vq;
|
|
}
|
|
|
|
|
|
/*
|
|
* Packed ring specific functions - *_packed().
|
|
*/
|
|
|
|
static void vring_unmap_state_packed(const struct vring_virtqueue *vq,
|
|
struct vring_desc_extra_packed *state)
|
|
{
|
|
u16 flags;
|
|
|
|
if (!vq->use_dma_api)
|
|
return;
|
|
|
|
flags = state->flags;
|
|
|
|
if (flags & VRING_DESC_F_INDIRECT) {
|
|
dma_unmap_single(vring_dma_dev(vq),
|
|
state->addr, state->len,
|
|
(flags & VRING_DESC_F_WRITE) ?
|
|
DMA_FROM_DEVICE : DMA_TO_DEVICE);
|
|
} else {
|
|
dma_unmap_page(vring_dma_dev(vq),
|
|
state->addr, state->len,
|
|
(flags & VRING_DESC_F_WRITE) ?
|
|
DMA_FROM_DEVICE : DMA_TO_DEVICE);
|
|
}
|
|
}
|
|
|
|
static void vring_unmap_desc_packed(const struct vring_virtqueue *vq,
|
|
struct vring_packed_desc *desc)
|
|
{
|
|
u16 flags;
|
|
|
|
if (!vq->use_dma_api)
|
|
return;
|
|
|
|
flags = le16_to_cpu(desc->flags);
|
|
|
|
if (flags & VRING_DESC_F_INDIRECT) {
|
|
dma_unmap_single(vring_dma_dev(vq),
|
|
le64_to_cpu(desc->addr),
|
|
le32_to_cpu(desc->len),
|
|
(flags & VRING_DESC_F_WRITE) ?
|
|
DMA_FROM_DEVICE : DMA_TO_DEVICE);
|
|
} else {
|
|
dma_unmap_page(vring_dma_dev(vq),
|
|
le64_to_cpu(desc->addr),
|
|
le32_to_cpu(desc->len),
|
|
(flags & VRING_DESC_F_WRITE) ?
|
|
DMA_FROM_DEVICE : DMA_TO_DEVICE);
|
|
}
|
|
}
|
|
|
|
static struct vring_packed_desc *alloc_indirect_packed(unsigned int total_sg,
|
|
gfp_t gfp)
|
|
{
|
|
struct vring_packed_desc *desc;
|
|
|
|
/*
|
|
* We require lowmem mappings for the descriptors because
|
|
* otherwise virt_to_phys will give us bogus addresses in the
|
|
* virtqueue.
|
|
*/
|
|
gfp &= ~__GFP_HIGHMEM;
|
|
|
|
desc = kmalloc_array(total_sg, sizeof(struct vring_packed_desc), gfp);
|
|
|
|
return desc;
|
|
}
|
|
|
|
static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
|
|
struct scatterlist *sgs[],
|
|
unsigned int total_sg,
|
|
unsigned int out_sgs,
|
|
unsigned int in_sgs,
|
|
void *data,
|
|
gfp_t gfp)
|
|
{
|
|
struct vring_packed_desc *desc;
|
|
struct scatterlist *sg;
|
|
unsigned int i, n, err_idx;
|
|
u16 head, id;
|
|
dma_addr_t addr;
|
|
|
|
head = vq->packed.next_avail_idx;
|
|
desc = alloc_indirect_packed(total_sg, gfp);
|
|
|
|
if (unlikely(vq->vq.num_free < 1)) {
|
|
pr_debug("Can't add buf len 1 - avail = 0\n");
|
|
kfree(desc);
|
|
END_USE(vq);
|
|
return -ENOSPC;
|
|
}
|
|
|
|
i = 0;
|
|
id = vq->free_head;
|
|
BUG_ON(id == vq->packed.vring.num);
|
|
|
|
for (n = 0; n < out_sgs + in_sgs; n++) {
|
|
for (sg = sgs[n]; sg; sg = sg_next(sg)) {
|
|
addr = vring_map_one_sg(vq, sg, n < out_sgs ?
|
|
DMA_TO_DEVICE : DMA_FROM_DEVICE);
|
|
if (vring_mapping_error(vq, addr))
|
|
goto unmap_release;
|
|
|
|
desc[i].flags = cpu_to_le16(n < out_sgs ?
|
|
0 : VRING_DESC_F_WRITE);
|
|
desc[i].addr = cpu_to_le64(addr);
|
|
desc[i].len = cpu_to_le32(sg->length);
|
|
i++;
|
|
}
|
|
}
|
|
|
|
/* Now that the indirect table is filled in, map it. */
|
|
addr = vring_map_single(vq, desc,
|
|
total_sg * sizeof(struct vring_packed_desc),
|
|
DMA_TO_DEVICE);
|
|
if (vring_mapping_error(vq, addr))
|
|
goto unmap_release;
|
|
|
|
vq->packed.vring.desc[head].addr = cpu_to_le64(addr);
|
|
vq->packed.vring.desc[head].len = cpu_to_le32(total_sg *
|
|
sizeof(struct vring_packed_desc));
|
|
vq->packed.vring.desc[head].id = cpu_to_le16(id);
|
|
|
|
if (vq->use_dma_api) {
|
|
vq->packed.desc_extra[id].addr = addr;
|
|
vq->packed.desc_extra[id].len = total_sg *
|
|
sizeof(struct vring_packed_desc);
|
|
vq->packed.desc_extra[id].flags = VRING_DESC_F_INDIRECT |
|
|
vq->packed.avail_used_flags;
|
|
}
|
|
|
|
/*
|
|
* A driver MUST NOT make the first descriptor in the list
|
|
* available before all subsequent descriptors comprising
|
|
* the list are made available.
|
|
*/
|
|
virtio_wmb(vq->weak_barriers);
|
|
vq->packed.vring.desc[head].flags = cpu_to_le16(VRING_DESC_F_INDIRECT |
|
|
vq->packed.avail_used_flags);
|
|
|
|
/* We're using some buffers from the free list. */
|
|
vq->vq.num_free -= 1;
|
|
|
|
/* Update free pointer */
|
|
n = head + 1;
|
|
if (n >= vq->packed.vring.num) {
|
|
n = 0;
|
|
vq->packed.avail_wrap_counter ^= 1;
|
|
vq->packed.avail_used_flags ^=
|
|
1 << VRING_PACKED_DESC_F_AVAIL |
|
|
1 << VRING_PACKED_DESC_F_USED;
|
|
}
|
|
vq->packed.next_avail_idx = n;
|
|
vq->free_head = vq->packed.desc_state[id].next;
|
|
|
|
/* Store token and indirect buffer state. */
|
|
vq->packed.desc_state[id].num = 1;
|
|
vq->packed.desc_state[id].data = data;
|
|
vq->packed.desc_state[id].indir_desc = desc;
|
|
vq->packed.desc_state[id].last = id;
|
|
|
|
vq->num_added += 1;
|
|
|
|
pr_debug("Added buffer head %i to %p\n", head, vq);
|
|
END_USE(vq);
|
|
|
|
return 0;
|
|
|
|
unmap_release:
|
|
err_idx = i;
|
|
|
|
for (i = 0; i < err_idx; i++)
|
|
vring_unmap_desc_packed(vq, &desc[i]);
|
|
|
|
kfree(desc);
|
|
|
|
END_USE(vq);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
static inline int virtqueue_add_packed(struct virtqueue *_vq,
|
|
struct scatterlist *sgs[],
|
|
unsigned int total_sg,
|
|
unsigned int out_sgs,
|
|
unsigned int in_sgs,
|
|
void *data,
|
|
void *ctx,
|
|
gfp_t gfp)
|
|
{
|
|
struct vring_virtqueue *vq = to_vvq(_vq);
|
|
struct vring_packed_desc *desc;
|
|
struct scatterlist *sg;
|
|
unsigned int i, n, c, descs_used, err_idx;
|
|
__le16 uninitialized_var(head_flags), flags;
|
|
u16 head, id, uninitialized_var(prev), curr, avail_used_flags;
|
|
|
|
START_USE(vq);
|
|
|
|
BUG_ON(data == NULL);
|
|
BUG_ON(ctx && vq->indirect);
|
|
|
|
if (unlikely(vq->broken)) {
|
|
END_USE(vq);
|
|
return -EIO;
|
|
}
|
|
|
|
LAST_ADD_TIME_UPDATE(vq);
|
|
|
|
BUG_ON(total_sg == 0);
|
|
|
|
if (virtqueue_use_indirect(_vq, total_sg))
|
|
return virtqueue_add_indirect_packed(vq, sgs, total_sg,
|
|
out_sgs, in_sgs, data, gfp);
|
|
|
|
head = vq->packed.next_avail_idx;
|
|
avail_used_flags = vq->packed.avail_used_flags;
|
|
|
|
WARN_ON_ONCE(total_sg > vq->packed.vring.num && !vq->indirect);
|
|
|
|
desc = vq->packed.vring.desc;
|
|
i = head;
|
|
descs_used = total_sg;
|
|
|
|
if (unlikely(vq->vq.num_free < descs_used)) {
|
|
pr_debug("Can't add buf len %i - avail = %i\n",
|
|
descs_used, vq->vq.num_free);
|
|
END_USE(vq);
|
|
return -ENOSPC;
|
|
}
|
|
|
|
id = vq->free_head;
|
|
BUG_ON(id == vq->packed.vring.num);
|
|
|
|
curr = id;
|
|
c = 0;
|
|
for (n = 0; n < out_sgs + in_sgs; n++) {
|
|
for (sg = sgs[n]; sg; sg = sg_next(sg)) {
|
|
dma_addr_t addr = vring_map_one_sg(vq, sg, n < out_sgs ?
|
|
DMA_TO_DEVICE : DMA_FROM_DEVICE);
|
|
if (vring_mapping_error(vq, addr))
|
|
goto unmap_release;
|
|
|
|
flags = cpu_to_le16(vq->packed.avail_used_flags |
|
|
(++c == total_sg ? 0 : VRING_DESC_F_NEXT) |
|
|
(n < out_sgs ? 0 : VRING_DESC_F_WRITE));
|
|
if (i == head)
|
|
head_flags = flags;
|
|
else
|
|
desc[i].flags = flags;
|
|
|
|
desc[i].addr = cpu_to_le64(addr);
|
|
desc[i].len = cpu_to_le32(sg->length);
|
|
desc[i].id = cpu_to_le16(id);
|
|
|
|
if (unlikely(vq->use_dma_api)) {
|
|
vq->packed.desc_extra[curr].addr = addr;
|
|
vq->packed.desc_extra[curr].len = sg->length;
|
|
vq->packed.desc_extra[curr].flags =
|
|
le16_to_cpu(flags);
|
|
}
|
|
prev = curr;
|
|
curr = vq->packed.desc_state[curr].next;
|
|
|
|
if ((unlikely(++i >= vq->packed.vring.num))) {
|
|
i = 0;
|
|
vq->packed.avail_used_flags ^=
|
|
1 << VRING_PACKED_DESC_F_AVAIL |
|
|
1 << VRING_PACKED_DESC_F_USED;
|
|
}
|
|
}
|
|
}
|
|
|
|
if (i < head)
|
|
vq->packed.avail_wrap_counter ^= 1;
|
|
|
|
/* We're using some buffers from the free list. */
|
|
vq->vq.num_free -= descs_used;
|
|
|
|
/* Update free pointer */
|
|
vq->packed.next_avail_idx = i;
|
|
vq->free_head = curr;
|
|
|
|
/* Store token. */
|
|
vq->packed.desc_state[id].num = descs_used;
|
|
vq->packed.desc_state[id].data = data;
|
|
vq->packed.desc_state[id].indir_desc = ctx;
|
|
vq->packed.desc_state[id].last = prev;
|
|
|
|
/*
|
|
* A driver MUST NOT make the first descriptor in the list
|
|
* available before all subsequent descriptors comprising
|
|
* the list are made available.
|
|
*/
|
|
virtio_wmb(vq->weak_barriers);
|
|
vq->packed.vring.desc[head].flags = head_flags;
|
|
vq->num_added += descs_used;
|
|
|
|
pr_debug("Added buffer head %i to %p\n", head, vq);
|
|
END_USE(vq);
|
|
|
|
return 0;
|
|
|
|
unmap_release:
|
|
err_idx = i;
|
|
i = head;
|
|
|
|
vq->packed.avail_used_flags = avail_used_flags;
|
|
|
|
for (n = 0; n < total_sg; n++) {
|
|
if (i == err_idx)
|
|
break;
|
|
vring_unmap_desc_packed(vq, &desc[i]);
|
|
i++;
|
|
if (i >= vq->packed.vring.num)
|
|
i = 0;
|
|
}
|
|
|
|
END_USE(vq);
|
|
return -EIO;
|
|
}
|
|
|
|
static bool virtqueue_kick_prepare_packed(struct virtqueue *_vq)
|
|
{
|
|
struct vring_virtqueue *vq = to_vvq(_vq);
|
|
u16 new, old, off_wrap, flags, wrap_counter, event_idx;
|
|
bool needs_kick;
|
|
union {
|
|
struct {
|
|
__le16 off_wrap;
|
|
__le16 flags;
|
|
};
|
|
u32 u32;
|
|
} snapshot;
|
|
|
|
START_USE(vq);
|
|
|
|
/*
|
|
* We need to expose the new flags value before checking notification
|
|
* suppressions.
|
|
*/
|
|
virtio_mb(vq->weak_barriers);
|
|
|
|
old = vq->packed.next_avail_idx - vq->num_added;
|
|
new = vq->packed.next_avail_idx;
|
|
vq->num_added = 0;
|
|
|
|
snapshot.u32 = *(u32 *)vq->packed.vring.device;
|
|
flags = le16_to_cpu(snapshot.flags);
|
|
|
|
LAST_ADD_TIME_CHECK(vq);
|
|
LAST_ADD_TIME_INVALID(vq);
|
|
|
|
if (flags != VRING_PACKED_EVENT_FLAG_DESC) {
|
|
needs_kick = (flags != VRING_PACKED_EVENT_FLAG_DISABLE);
|
|
goto out;
|
|
}
|
|
|
|
off_wrap = le16_to_cpu(snapshot.off_wrap);
|
|
|
|
wrap_counter = off_wrap >> VRING_PACKED_EVENT_F_WRAP_CTR;
|
|
event_idx = off_wrap & ~(1 << VRING_PACKED_EVENT_F_WRAP_CTR);
|
|
if (wrap_counter != vq->packed.avail_wrap_counter)
|
|
event_idx -= vq->packed.vring.num;
|
|
|
|
needs_kick = vring_need_event(event_idx, new, old);
|
|
out:
|
|
END_USE(vq);
|
|
return needs_kick;
|
|
}
|
|
|
|
static void detach_buf_packed(struct vring_virtqueue *vq,
|
|
unsigned int id, void **ctx)
|
|
{
|
|
struct vring_desc_state_packed *state = NULL;
|
|
struct vring_packed_desc *desc;
|
|
unsigned int i, curr;
|
|
|
|
state = &vq->packed.desc_state[id];
|
|
|
|
/* Clear data ptr. */
|
|
state->data = NULL;
|
|
|
|
vq->packed.desc_state[state->last].next = vq->free_head;
|
|
vq->free_head = id;
|
|
vq->vq.num_free += state->num;
|
|
|
|
if (unlikely(vq->use_dma_api)) {
|
|
curr = id;
|
|
for (i = 0; i < state->num; i++) {
|
|
vring_unmap_state_packed(vq,
|
|
&vq->packed.desc_extra[curr]);
|
|
curr = vq->packed.desc_state[curr].next;
|
|
}
|
|
}
|
|
|
|
if (vq->indirect) {
|
|
u32 len;
|
|
|
|
/* Free the indirect table, if any, now that it's unmapped. */
|
|
desc = state->indir_desc;
|
|
if (!desc)
|
|
return;
|
|
|
|
if (vq->use_dma_api) {
|
|
len = vq->packed.desc_extra[id].len;
|
|
for (i = 0; i < len / sizeof(struct vring_packed_desc);
|
|
i++)
|
|
vring_unmap_desc_packed(vq, &desc[i]);
|
|
}
|
|
kfree(desc);
|
|
state->indir_desc = NULL;
|
|
} else if (ctx) {
|
|
*ctx = state->indir_desc;
|
|
}
|
|
}
|
|
|
|
static inline bool is_used_desc_packed(const struct vring_virtqueue *vq,
|
|
u16 idx, bool used_wrap_counter)
|
|
{
|
|
bool avail, used;
|
|
u16 flags;
|
|
|
|
flags = le16_to_cpu(vq->packed.vring.desc[idx].flags);
|
|
avail = !!(flags & (1 << VRING_PACKED_DESC_F_AVAIL));
|
|
used = !!(flags & (1 << VRING_PACKED_DESC_F_USED));
|
|
|
|
return avail == used && used == used_wrap_counter;
|
|
}
|
|
|
|
static inline bool more_used_packed(const struct vring_virtqueue *vq)
|
|
{
|
|
return is_used_desc_packed(vq, vq->last_used_idx,
|
|
vq->packed.used_wrap_counter);
|
|
}
|
|
|
|
static void *virtqueue_get_buf_ctx_packed(struct virtqueue *_vq,
|
|
unsigned int *len,
|
|
void **ctx)
|
|
{
|
|
struct vring_virtqueue *vq = to_vvq(_vq);
|
|
u16 last_used, id;
|
|
void *ret;
|
|
|
|
START_USE(vq);
|
|
|
|
if (unlikely(vq->broken)) {
|
|
END_USE(vq);
|
|
return NULL;
|
|
}
|
|
|
|
if (!more_used_packed(vq)) {
|
|
pr_debug("No more buffers in queue\n");
|
|
END_USE(vq);
|
|
return NULL;
|
|
}
|
|
|
|
/* Only get used elements after they have been exposed by host. */
|
|
virtio_rmb(vq->weak_barriers);
|
|
|
|
last_used = vq->last_used_idx;
|
|
id = le16_to_cpu(vq->packed.vring.desc[last_used].id);
|
|
*len = le32_to_cpu(vq->packed.vring.desc[last_used].len);
|
|
|
|
if (unlikely(id >= vq->packed.vring.num)) {
|
|
BAD_RING(vq, "id %u out of range\n", id);
|
|
return NULL;
|
|
}
|
|
if (unlikely(!vq->packed.desc_state[id].data)) {
|
|
BAD_RING(vq, "id %u is not a head!\n", id);
|
|
return NULL;
|
|
}
|
|
|
|
/* detach_buf_packed clears data, so grab it now. */
|
|
ret = vq->packed.desc_state[id].data;
|
|
detach_buf_packed(vq, id, ctx);
|
|
|
|
vq->last_used_idx += vq->packed.desc_state[id].num;
|
|
if (unlikely(vq->last_used_idx >= vq->packed.vring.num)) {
|
|
vq->last_used_idx -= vq->packed.vring.num;
|
|
vq->packed.used_wrap_counter ^= 1;
|
|
}
|
|
|
|
/*
|
|
* If we expect an interrupt for the next entry, tell host
|
|
* by writing event index and flush out the write before
|
|
* the read in the next get_buf call.
|
|
*/
|
|
if (vq->packed.event_flags_shadow == VRING_PACKED_EVENT_FLAG_DESC)
|
|
virtio_store_mb(vq->weak_barriers,
|
|
&vq->packed.vring.driver->off_wrap,
|
|
cpu_to_le16(vq->last_used_idx |
|
|
(vq->packed.used_wrap_counter <<
|
|
VRING_PACKED_EVENT_F_WRAP_CTR)));
|
|
|
|
LAST_ADD_TIME_INVALID(vq);
|
|
|
|
END_USE(vq);
|
|
return ret;
|
|
}
|
|
|
|
static void virtqueue_disable_cb_packed(struct virtqueue *_vq)
|
|
{
|
|
struct vring_virtqueue *vq = to_vvq(_vq);
|
|
|
|
if (vq->packed.event_flags_shadow != VRING_PACKED_EVENT_FLAG_DISABLE) {
|
|
vq->packed.event_flags_shadow = VRING_PACKED_EVENT_FLAG_DISABLE;
|
|
vq->packed.vring.driver->flags =
|
|
cpu_to_le16(vq->packed.event_flags_shadow);
|
|
}
|
|
}
|
|
|
|
static unsigned virtqueue_enable_cb_prepare_packed(struct virtqueue *_vq)
|
|
{
|
|
struct vring_virtqueue *vq = to_vvq(_vq);
|
|
|
|
START_USE(vq);
|
|
|
|
/*
|
|
* We optimistically turn back on interrupts, then check if there was
|
|
* more to do.
|
|
*/
|
|
|
|
if (vq->event) {
|
|
vq->packed.vring.driver->off_wrap =
|
|
cpu_to_le16(vq->last_used_idx |
|
|
(vq->packed.used_wrap_counter <<
|
|
VRING_PACKED_EVENT_F_WRAP_CTR));
|
|
/*
|
|
* We need to update event offset and event wrap
|
|
* counter first before updating event flags.
|
|
*/
|
|
virtio_wmb(vq->weak_barriers);
|
|
}
|
|
|
|
if (vq->packed.event_flags_shadow == VRING_PACKED_EVENT_FLAG_DISABLE) {
|
|
vq->packed.event_flags_shadow = vq->event ?
|
|
VRING_PACKED_EVENT_FLAG_DESC :
|
|
VRING_PACKED_EVENT_FLAG_ENABLE;
|
|
vq->packed.vring.driver->flags =
|
|
cpu_to_le16(vq->packed.event_flags_shadow);
|
|
}
|
|
|
|
END_USE(vq);
|
|
return vq->last_used_idx | ((u16)vq->packed.used_wrap_counter <<
|
|
VRING_PACKED_EVENT_F_WRAP_CTR);
|
|
}
|
|
|
|
static bool virtqueue_poll_packed(struct virtqueue *_vq, u16 off_wrap)
|
|
{
|
|
struct vring_virtqueue *vq = to_vvq(_vq);
|
|
bool wrap_counter;
|
|
u16 used_idx;
|
|
|
|
wrap_counter = off_wrap >> VRING_PACKED_EVENT_F_WRAP_CTR;
|
|
used_idx = off_wrap & ~(1 << VRING_PACKED_EVENT_F_WRAP_CTR);
|
|
|
|
return is_used_desc_packed(vq, used_idx, wrap_counter);
|
|
}
|
|
|
|
static bool virtqueue_enable_cb_delayed_packed(struct virtqueue *_vq)
|
|
{
|
|
struct vring_virtqueue *vq = to_vvq(_vq);
|
|
u16 used_idx, wrap_counter;
|
|
u16 bufs;
|
|
|
|
START_USE(vq);
|
|
|
|
/*
|
|
* We optimistically turn back on interrupts, then check if there was
|
|
* more to do.
|
|
*/
|
|
|
|
if (vq->event) {
|
|
/* TODO: tune this threshold */
|
|
bufs = (vq->packed.vring.num - vq->vq.num_free) * 3 / 4;
|
|
wrap_counter = vq->packed.used_wrap_counter;
|
|
|
|
used_idx = vq->last_used_idx + bufs;
|
|
if (used_idx >= vq->packed.vring.num) {
|
|
used_idx -= vq->packed.vring.num;
|
|
wrap_counter ^= 1;
|
|
}
|
|
|
|
vq->packed.vring.driver->off_wrap = cpu_to_le16(used_idx |
|
|
(wrap_counter << VRING_PACKED_EVENT_F_WRAP_CTR));
|
|
|
|
/*
|
|
* We need to update event offset and event wrap
|
|
* counter first before updating event flags.
|
|
*/
|
|
virtio_wmb(vq->weak_barriers);
|
|
}
|
|
|
|
if (vq->packed.event_flags_shadow == VRING_PACKED_EVENT_FLAG_DISABLE) {
|
|
vq->packed.event_flags_shadow = vq->event ?
|
|
VRING_PACKED_EVENT_FLAG_DESC :
|
|
VRING_PACKED_EVENT_FLAG_ENABLE;
|
|
vq->packed.vring.driver->flags =
|
|
cpu_to_le16(vq->packed.event_flags_shadow);
|
|
}
|
|
|
|
/*
|
|
* We need to update event suppression structure first
|
|
* before re-checking for more used buffers.
|
|
*/
|
|
virtio_mb(vq->weak_barriers);
|
|
|
|
if (is_used_desc_packed(vq,
|
|
vq->last_used_idx,
|
|
vq->packed.used_wrap_counter)) {
|
|
END_USE(vq);
|
|
return false;
|
|
}
|
|
|
|
END_USE(vq);
|
|
return true;
|
|
}
|
|
|
|
static void *virtqueue_detach_unused_buf_packed(struct virtqueue *_vq)
|
|
{
|
|
struct vring_virtqueue *vq = to_vvq(_vq);
|
|
unsigned int i;
|
|
void *buf;
|
|
|
|
START_USE(vq);
|
|
|
|
for (i = 0; i < vq->packed.vring.num; i++) {
|
|
if (!vq->packed.desc_state[i].data)
|
|
continue;
|
|
/* detach_buf clears data, so grab it now. */
|
|
buf = vq->packed.desc_state[i].data;
|
|
detach_buf_packed(vq, i, NULL);
|
|
END_USE(vq);
|
|
return buf;
|
|
}
|
|
/* That should have freed everything. */
|
|
BUG_ON(vq->vq.num_free != vq->packed.vring.num);
|
|
|
|
END_USE(vq);
|
|
return NULL;
|
|
}
|
|
|
|
static struct virtqueue *vring_create_virtqueue_packed(
|
|
unsigned int index,
|
|
unsigned int num,
|
|
unsigned int vring_align,
|
|
struct virtio_device *vdev,
|
|
bool weak_barriers,
|
|
bool may_reduce_num,
|
|
bool context,
|
|
bool (*notify)(struct virtqueue *),
|
|
void (*callback)(struct virtqueue *),
|
|
const char *name)
|
|
{
|
|
struct vring_virtqueue *vq;
|
|
struct vring_packed_desc *ring;
|
|
struct vring_packed_desc_event *driver, *device;
|
|
dma_addr_t ring_dma_addr, driver_event_dma_addr, device_event_dma_addr;
|
|
size_t ring_size_in_bytes, event_size_in_bytes;
|
|
unsigned int i;
|
|
|
|
ring_size_in_bytes = num * sizeof(struct vring_packed_desc);
|
|
|
|
ring = vring_alloc_queue(vdev, ring_size_in_bytes,
|
|
&ring_dma_addr,
|
|
GFP_KERNEL|__GFP_NOWARN|__GFP_ZERO);
|
|
if (!ring)
|
|
goto err_ring;
|
|
|
|
event_size_in_bytes = sizeof(struct vring_packed_desc_event);
|
|
|
|
driver = vring_alloc_queue(vdev, event_size_in_bytes,
|
|
&driver_event_dma_addr,
|
|
GFP_KERNEL|__GFP_NOWARN|__GFP_ZERO);
|
|
if (!driver)
|
|
goto err_driver;
|
|
|
|
device = vring_alloc_queue(vdev, event_size_in_bytes,
|
|
&device_event_dma_addr,
|
|
GFP_KERNEL|__GFP_NOWARN|__GFP_ZERO);
|
|
if (!device)
|
|
goto err_device;
|
|
|
|
vq = kmalloc(sizeof(*vq), GFP_KERNEL);
|
|
if (!vq)
|
|
goto err_vq;
|
|
|
|
vq->vq.callback = callback;
|
|
vq->vq.vdev = vdev;
|
|
vq->vq.name = name;
|
|
vq->vq.num_free = num;
|
|
vq->vq.index = index;
|
|
vq->we_own_ring = true;
|
|
vq->notify = notify;
|
|
vq->weak_barriers = weak_barriers;
|
|
vq->broken = false;
|
|
vq->last_used_idx = 0;
|
|
vq->num_added = 0;
|
|
vq->packed_ring = true;
|
|
vq->use_dma_api = vring_use_dma_api(vdev);
|
|
list_add_tail(&vq->vq.list, &vdev->vqs);
|
|
#ifdef DEBUG
|
|
vq->in_use = false;
|
|
vq->last_add_time_valid = false;
|
|
#endif
|
|
|
|
vq->indirect = virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC) &&
|
|
!context;
|
|
vq->event = virtio_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX);
|
|
|
|
if (virtio_has_feature(vdev, VIRTIO_F_ORDER_PLATFORM))
|
|
vq->weak_barriers = false;
|
|
|
|
vq->packed.ring_dma_addr = ring_dma_addr;
|
|
vq->packed.driver_event_dma_addr = driver_event_dma_addr;
|
|
vq->packed.device_event_dma_addr = device_event_dma_addr;
|
|
|
|
vq->packed.ring_size_in_bytes = ring_size_in_bytes;
|
|
vq->packed.event_size_in_bytes = event_size_in_bytes;
|
|
|
|
vq->packed.vring.num = num;
|
|
vq->packed.vring.desc = ring;
|
|
vq->packed.vring.driver = driver;
|
|
vq->packed.vring.device = device;
|
|
|
|
vq->packed.next_avail_idx = 0;
|
|
vq->packed.avail_wrap_counter = 1;
|
|
vq->packed.used_wrap_counter = 1;
|
|
vq->packed.event_flags_shadow = 0;
|
|
vq->packed.avail_used_flags = 1 << VRING_PACKED_DESC_F_AVAIL;
|
|
|
|
vq->packed.desc_state = kmalloc_array(num,
|
|
sizeof(struct vring_desc_state_packed),
|
|
GFP_KERNEL);
|
|
if (!vq->packed.desc_state)
|
|
goto err_desc_state;
|
|
|
|
memset(vq->packed.desc_state, 0,
|
|
num * sizeof(struct vring_desc_state_packed));
|
|
|
|
/* Put everything in free lists. */
|
|
vq->free_head = 0;
|
|
for (i = 0; i < num-1; i++)
|
|
vq->packed.desc_state[i].next = i + 1;
|
|
|
|
vq->packed.desc_extra = kmalloc_array(num,
|
|
sizeof(struct vring_desc_extra_packed),
|
|
GFP_KERNEL);
|
|
if (!vq->packed.desc_extra)
|
|
goto err_desc_extra;
|
|
|
|
memset(vq->packed.desc_extra, 0,
|
|
num * sizeof(struct vring_desc_extra_packed));
|
|
|
|
/* No callback? Tell other side not to bother us. */
|
|
if (!callback) {
|
|
vq->packed.event_flags_shadow = VRING_PACKED_EVENT_FLAG_DISABLE;
|
|
vq->packed.vring.driver->flags =
|
|
cpu_to_le16(vq->packed.event_flags_shadow);
|
|
}
|
|
|
|
return &vq->vq;
|
|
|
|
err_desc_extra:
|
|
kfree(vq->packed.desc_state);
|
|
err_desc_state:
|
|
kfree(vq);
|
|
err_vq:
|
|
vring_free_queue(vdev, event_size_in_bytes, device, ring_dma_addr);
|
|
err_device:
|
|
vring_free_queue(vdev, event_size_in_bytes, driver, ring_dma_addr);
|
|
err_driver:
|
|
vring_free_queue(vdev, ring_size_in_bytes, ring, ring_dma_addr);
|
|
err_ring:
|
|
return NULL;
|
|
}
|
|
|
|
|
|
/*
|
|
* Generic functions and exported symbols.
|
|
*/
|
|
|
|
static inline int virtqueue_add(struct virtqueue *_vq,
|
|
struct scatterlist *sgs[],
|
|
unsigned int total_sg,
|
|
unsigned int out_sgs,
|
|
unsigned int in_sgs,
|
|
void *data,
|
|
void *ctx,
|
|
gfp_t gfp)
|
|
{
|
|
struct vring_virtqueue *vq = to_vvq(_vq);
|
|
|
|
return vq->packed_ring ? virtqueue_add_packed(_vq, sgs, total_sg,
|
|
out_sgs, in_sgs, data, ctx, gfp) :
|
|
virtqueue_add_split(_vq, sgs, total_sg,
|
|
out_sgs, in_sgs, data, ctx, gfp);
|
|
}
|
|
|
|
/**
|
|
* virtqueue_add_sgs - expose buffers to other end
|
|
* @_vq: the struct virtqueue we're talking about.
|
|
* @sgs: array of terminated scatterlists.
|
|
* @out_sgs: the number of scatterlists readable by other side
|
|
* @in_sgs: the number of scatterlists which are writable (after readable ones)
|
|
* @data: the token identifying the buffer.
|
|
* @gfp: how to do memory allocations (if necessary).
|
|
*
|
|
* Caller must ensure we don't call this with other virtqueue operations
|
|
* at the same time (except where noted).
|
|
*
|
|
* Returns zero or a negative error (ie. ENOSPC, ENOMEM, EIO).
|
|
*/
|
|
int virtqueue_add_sgs(struct virtqueue *_vq,
|
|
struct scatterlist *sgs[],
|
|
unsigned int out_sgs,
|
|
unsigned int in_sgs,
|
|
void *data,
|
|
gfp_t gfp)
|
|
{
|
|
unsigned int i, total_sg = 0;
|
|
|
|
/* Count them first. */
|
|
for (i = 0; i < out_sgs + in_sgs; i++) {
|
|
struct scatterlist *sg;
|
|
|
|
for (sg = sgs[i]; sg; sg = sg_next(sg))
|
|
total_sg++;
|
|
}
|
|
return virtqueue_add(_vq, sgs, total_sg, out_sgs, in_sgs,
|
|
data, NULL, gfp);
|
|
}
|
|
EXPORT_SYMBOL_GPL(virtqueue_add_sgs);
|
|
|
|
/**
|
|
* virtqueue_add_outbuf - expose output buffers to other end
|
|
* @vq: the struct virtqueue we're talking about.
|
|
* @sg: scatterlist (must be well-formed and terminated!)
|
|
* @num: the number of entries in @sg readable by other side
|
|
* @data: the token identifying the buffer.
|
|
* @gfp: how to do memory allocations (if necessary).
|
|
*
|
|
* Caller must ensure we don't call this with other virtqueue operations
|
|
* at the same time (except where noted).
|
|
*
|
|
* Returns zero or a negative error (ie. ENOSPC, ENOMEM, EIO).
|
|
*/
|
|
int virtqueue_add_outbuf(struct virtqueue *vq,
|
|
struct scatterlist *sg, unsigned int num,
|
|
void *data,
|
|
gfp_t gfp)
|
|
{
|
|
return virtqueue_add(vq, &sg, num, 1, 0, data, NULL, gfp);
|
|
}
|
|
EXPORT_SYMBOL_GPL(virtqueue_add_outbuf);
|
|
|
|
/**
|
|
* virtqueue_add_inbuf - expose input buffers to other end
|
|
* @vq: the struct virtqueue we're talking about.
|
|
* @sg: scatterlist (must be well-formed and terminated!)
|
|
* @num: the number of entries in @sg writable by other side
|
|
* @data: the token identifying the buffer.
|
|
* @gfp: how to do memory allocations (if necessary).
|
|
*
|
|
* Caller must ensure we don't call this with other virtqueue operations
|
|
* at the same time (except where noted).
|
|
*
|
|
* Returns zero or a negative error (ie. ENOSPC, ENOMEM, EIO).
|
|
*/
|
|
int virtqueue_add_inbuf(struct virtqueue *vq,
|
|
struct scatterlist *sg, unsigned int num,
|
|
void *data,
|
|
gfp_t gfp)
|
|
{
|
|
return virtqueue_add(vq, &sg, num, 0, 1, data, NULL, gfp);
|
|
}
|
|
EXPORT_SYMBOL_GPL(virtqueue_add_inbuf);
|
|
|
|
/**
|
|
* virtqueue_add_inbuf_ctx - expose input buffers to other end
|
|
* @vq: the struct virtqueue we're talking about.
|
|
* @sg: scatterlist (must be well-formed and terminated!)
|
|
* @num: the number of entries in @sg writable by other side
|
|
* @data: the token identifying the buffer.
|
|
* @ctx: extra context for the token
|
|
* @gfp: how to do memory allocations (if necessary).
|
|
*
|
|
* Caller must ensure we don't call this with other virtqueue operations
|
|
* at the same time (except where noted).
|
|
*
|
|
* Returns zero or a negative error (ie. ENOSPC, ENOMEM, EIO).
|
|
*/
|
|
int virtqueue_add_inbuf_ctx(struct virtqueue *vq,
|
|
struct scatterlist *sg, unsigned int num,
|
|
void *data,
|
|
void *ctx,
|
|
gfp_t gfp)
|
|
{
|
|
return virtqueue_add(vq, &sg, num, 0, 1, data, ctx, gfp);
|
|
}
|
|
EXPORT_SYMBOL_GPL(virtqueue_add_inbuf_ctx);
|
|
|
|
/**
|
|
* virtqueue_kick_prepare - first half of split virtqueue_kick call.
|
|
* @_vq: the struct virtqueue
|
|
*
|
|
* Instead of virtqueue_kick(), you can do:
|
|
* if (virtqueue_kick_prepare(vq))
|
|
* virtqueue_notify(vq);
|
|
*
|
|
* This is sometimes useful because the virtqueue_kick_prepare() needs
|
|
* to be serialized, but the actual virtqueue_notify() call does not.
|
|
*/
|
|
bool virtqueue_kick_prepare(struct virtqueue *_vq)
|
|
{
|
|
struct vring_virtqueue *vq = to_vvq(_vq);
|
|
|
|
return vq->packed_ring ? virtqueue_kick_prepare_packed(_vq) :
|
|
virtqueue_kick_prepare_split(_vq);
|
|
}
|
|
EXPORT_SYMBOL_GPL(virtqueue_kick_prepare);
|
|
|
|
/**
|
|
* virtqueue_notify - second half of split virtqueue_kick call.
|
|
* @_vq: the struct virtqueue
|
|
*
|
|
* This does not need to be serialized.
|
|
*
|
|
* Returns false if host notify failed or queue is broken, otherwise true.
|
|
*/
|
|
bool virtqueue_notify(struct virtqueue *_vq)
|
|
{
|
|
struct vring_virtqueue *vq = to_vvq(_vq);
|
|
|
|
if (unlikely(vq->broken))
|
|
return false;
|
|
|
|
/* Prod other side to tell it about changes. */
|
|
if (!vq->notify(_vq)) {
|
|
vq->broken = true;
|
|
return false;
|
|
}
|
|
return true;
|
|
}
|
|
EXPORT_SYMBOL_GPL(virtqueue_notify);
|
|
|
|
/**
|
|
* virtqueue_kick - update after add_buf
|
|
* @vq: the struct virtqueue
|
|
*
|
|
* After one or more virtqueue_add_* calls, invoke this to kick
|
|
* the other side.
|
|
*
|
|
* Caller must ensure we don't call this with other virtqueue
|
|
* operations at the same time (except where noted).
|
|
*
|
|
* Returns false if kick failed, otherwise true.
|
|
*/
|
|
bool virtqueue_kick(struct virtqueue *vq)
|
|
{
|
|
if (virtqueue_kick_prepare(vq))
|
|
return virtqueue_notify(vq);
|
|
return true;
|
|
}
|
|
EXPORT_SYMBOL_GPL(virtqueue_kick);
|
|
|
|
/**
|
|
* virtqueue_get_buf - get the next used buffer
|
|
* @_vq: the struct virtqueue we're talking about.
|
|
* @len: the length written into the buffer
|
|
* @ctx: extra context for the token
|
|
*
|
|
* If the device wrote data into the buffer, @len will be set to the
|
|
* amount written. This means you don't need to clear the buffer
|
|
* beforehand to ensure there's no data leakage in the case of short
|
|
* writes.
|
|
*
|
|
* Caller must ensure we don't call this with other virtqueue
|
|
* operations at the same time (except where noted).
|
|
*
|
|
* Returns NULL if there are no used buffers, or the "data" token
|
|
* handed to virtqueue_add_*().
|
|
*/
|
|
void *virtqueue_get_buf_ctx(struct virtqueue *_vq, unsigned int *len,
|
|
void **ctx)
|
|
{
|
|
struct vring_virtqueue *vq = to_vvq(_vq);
|
|
|
|
return vq->packed_ring ? virtqueue_get_buf_ctx_packed(_vq, len, ctx) :
|
|
virtqueue_get_buf_ctx_split(_vq, len, ctx);
|
|
}
|
|
EXPORT_SYMBOL_GPL(virtqueue_get_buf_ctx);
|
|
|
|
void *virtqueue_get_buf(struct virtqueue *_vq, unsigned int *len)
|
|
{
|
|
return virtqueue_get_buf_ctx(_vq, len, NULL);
|
|
}
|
|
EXPORT_SYMBOL_GPL(virtqueue_get_buf);
|
|
/**
|
|
* virtqueue_disable_cb - disable callbacks
|
|
* @_vq: the struct virtqueue we're talking about.
|
|
*
|
|
* Note that this is not necessarily synchronous, hence unreliable and only
|
|
* useful as an optimization.
|
|
*
|
|
* Unlike other operations, this need not be serialized.
|
|
*/
|
|
void virtqueue_disable_cb(struct virtqueue *_vq)
|
|
{
|
|
struct vring_virtqueue *vq = to_vvq(_vq);
|
|
|
|
if (vq->packed_ring)
|
|
virtqueue_disable_cb_packed(_vq);
|
|
else
|
|
virtqueue_disable_cb_split(_vq);
|
|
}
|
|
EXPORT_SYMBOL_GPL(virtqueue_disable_cb);
|
|
|
|
/**
|
|
* virtqueue_enable_cb_prepare - restart callbacks after disable_cb
|
|
* @_vq: the struct virtqueue we're talking about.
|
|
*
|
|
* This re-enables callbacks; it returns current queue state
|
|
* in an opaque unsigned value. This value should be later tested by
|
|
* virtqueue_poll, to detect a possible race between the driver checking for
|
|
* more work, and enabling callbacks.
|
|
*
|
|
* Caller must ensure we don't call this with other virtqueue
|
|
* operations at the same time (except where noted).
|
|
*/
|
|
unsigned virtqueue_enable_cb_prepare(struct virtqueue *_vq)
|
|
{
|
|
struct vring_virtqueue *vq = to_vvq(_vq);
|
|
|
|
return vq->packed_ring ? virtqueue_enable_cb_prepare_packed(_vq) :
|
|
virtqueue_enable_cb_prepare_split(_vq);
|
|
}
|
|
EXPORT_SYMBOL_GPL(virtqueue_enable_cb_prepare);
|
|
|
|
/**
|
|
* virtqueue_poll - query pending used buffers
|
|
* @_vq: the struct virtqueue we're talking about.
|
|
* @last_used_idx: virtqueue state (from call to virtqueue_enable_cb_prepare).
|
|
*
|
|
* Returns "true" if there are pending used buffers in the queue.
|
|
*
|
|
* This does not need to be serialized.
|
|
*/
|
|
bool virtqueue_poll(struct virtqueue *_vq, unsigned last_used_idx)
|
|
{
|
|
struct vring_virtqueue *vq = to_vvq(_vq);
|
|
|
|
virtio_mb(vq->weak_barriers);
|
|
return vq->packed_ring ? virtqueue_poll_packed(_vq, last_used_idx) :
|
|
virtqueue_poll_split(_vq, last_used_idx);
|
|
}
|
|
EXPORT_SYMBOL_GPL(virtqueue_poll);
|
|
|
|
/**
|
|
* virtqueue_enable_cb - restart callbacks after disable_cb.
|
|
* @_vq: the struct virtqueue we're talking about.
|
|
*
|
|
* This re-enables callbacks; it returns "false" if there are pending
|
|
* buffers in the queue, to detect a possible race between the driver
|
|
* checking for more work, and enabling callbacks.
|
|
*
|
|
* Caller must ensure we don't call this with other virtqueue
|
|
* operations at the same time (except where noted).
|
|
*/
|
|
bool virtqueue_enable_cb(struct virtqueue *_vq)
|
|
{
|
|
unsigned last_used_idx = virtqueue_enable_cb_prepare(_vq);
|
|
|
|
return !virtqueue_poll(_vq, last_used_idx);
|
|
}
|
|
EXPORT_SYMBOL_GPL(virtqueue_enable_cb);
|
|
|
|
/**
|
|
* virtqueue_enable_cb_delayed - restart callbacks after disable_cb.
|
|
* @_vq: the struct virtqueue we're talking about.
|
|
*
|
|
* This re-enables callbacks but hints to the other side to delay
|
|
* interrupts until most of the available buffers have been processed;
|
|
* it returns "false" if there are many pending buffers in the queue,
|
|
* to detect a possible race between the driver checking for more work,
|
|
* and enabling callbacks.
|
|
*
|
|
* Caller must ensure we don't call this with other virtqueue
|
|
* operations at the same time (except where noted).
|
|
*/
|
|
bool virtqueue_enable_cb_delayed(struct virtqueue *_vq)
|
|
{
|
|
struct vring_virtqueue *vq = to_vvq(_vq);
|
|
|
|
return vq->packed_ring ? virtqueue_enable_cb_delayed_packed(_vq) :
|
|
virtqueue_enable_cb_delayed_split(_vq);
|
|
}
|
|
EXPORT_SYMBOL_GPL(virtqueue_enable_cb_delayed);
|
|
|
|
/**
|
|
* virtqueue_detach_unused_buf - detach first unused buffer
|
|
* @_vq: the struct virtqueue we're talking about.
|
|
*
|
|
* Returns NULL or the "data" token handed to virtqueue_add_*().
|
|
* This is not valid on an active queue; it is useful only for device
|
|
* shutdown.
|
|
*/
|
|
void *virtqueue_detach_unused_buf(struct virtqueue *_vq)
|
|
{
|
|
struct vring_virtqueue *vq = to_vvq(_vq);
|
|
|
|
return vq->packed_ring ? virtqueue_detach_unused_buf_packed(_vq) :
|
|
virtqueue_detach_unused_buf_split(_vq);
|
|
}
|
|
EXPORT_SYMBOL_GPL(virtqueue_detach_unused_buf);
|
|
|
|
static inline bool more_used(const struct vring_virtqueue *vq)
|
|
{
|
|
return vq->packed_ring ? more_used_packed(vq) : more_used_split(vq);
|
|
}
|
|
|
|
irqreturn_t vring_interrupt(int irq, void *_vq)
|
|
{
|
|
struct vring_virtqueue *vq = to_vvq(_vq);
|
|
|
|
if (!more_used(vq)) {
|
|
pr_debug("virtqueue interrupt with no work for %p\n", vq);
|
|
return IRQ_NONE;
|
|
}
|
|
|
|
if (unlikely(vq->broken))
|
|
return IRQ_HANDLED;
|
|
|
|
pr_debug("virtqueue callback for %p (%p)\n", vq, vq->vq.callback);
|
|
if (vq->vq.callback)
|
|
vq->vq.callback(&vq->vq);
|
|
|
|
return IRQ_HANDLED;
|
|
}
|
|
EXPORT_SYMBOL_GPL(vring_interrupt);
|
|
|
|
/* Only available for split ring */
|
|
struct virtqueue *__vring_new_virtqueue(unsigned int index,
|
|
struct vring vring,
|
|
struct virtio_device *vdev,
|
|
bool weak_barriers,
|
|
bool context,
|
|
bool (*notify)(struct virtqueue *),
|
|
void (*callback)(struct virtqueue *),
|
|
const char *name)
|
|
{
|
|
unsigned int i;
|
|
struct vring_virtqueue *vq;
|
|
|
|
if (virtio_has_feature(vdev, VIRTIO_F_RING_PACKED))
|
|
return NULL;
|
|
|
|
vq = kmalloc(sizeof(*vq), GFP_KERNEL);
|
|
if (!vq)
|
|
return NULL;
|
|
|
|
vq->packed_ring = false;
|
|
vq->vq.callback = callback;
|
|
vq->vq.vdev = vdev;
|
|
vq->vq.name = name;
|
|
vq->vq.num_free = vring.num;
|
|
vq->vq.index = index;
|
|
vq->we_own_ring = false;
|
|
vq->notify = notify;
|
|
vq->weak_barriers = weak_barriers;
|
|
vq->broken = false;
|
|
vq->last_used_idx = 0;
|
|
vq->num_added = 0;
|
|
vq->use_dma_api = vring_use_dma_api(vdev);
|
|
list_add_tail(&vq->vq.list, &vdev->vqs);
|
|
#ifdef DEBUG
|
|
vq->in_use = false;
|
|
vq->last_add_time_valid = false;
|
|
#endif
|
|
|
|
vq->indirect = virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC) &&
|
|
!context;
|
|
vq->event = virtio_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX);
|
|
|
|
if (virtio_has_feature(vdev, VIRTIO_F_ORDER_PLATFORM))
|
|
vq->weak_barriers = false;
|
|
|
|
vq->split.queue_dma_addr = 0;
|
|
vq->split.queue_size_in_bytes = 0;
|
|
|
|
vq->split.vring = vring;
|
|
vq->split.avail_flags_shadow = 0;
|
|
vq->split.avail_idx_shadow = 0;
|
|
|
|
/* No callback? Tell other side not to bother us. */
|
|
if (!callback) {
|
|
vq->split.avail_flags_shadow |= VRING_AVAIL_F_NO_INTERRUPT;
|
|
if (!vq->event)
|
|
vq->split.vring.avail->flags = cpu_to_virtio16(vdev,
|
|
vq->split.avail_flags_shadow);
|
|
}
|
|
|
|
vq->split.desc_state = kmalloc_array(vring.num,
|
|
sizeof(struct vring_desc_state_split), GFP_KERNEL);
|
|
if (!vq->split.desc_state) {
|
|
kfree(vq);
|
|
return NULL;
|
|
}
|
|
|
|
/* Put everything in free lists. */
|
|
vq->free_head = 0;
|
|
for (i = 0; i < vring.num-1; i++)
|
|
vq->split.vring.desc[i].next = cpu_to_virtio16(vdev, i + 1);
|
|
memset(vq->split.desc_state, 0, vring.num *
|
|
sizeof(struct vring_desc_state_split));
|
|
|
|
return &vq->vq;
|
|
}
|
|
EXPORT_SYMBOL_GPL(__vring_new_virtqueue);
|
|
|
|
struct virtqueue *vring_create_virtqueue(
|
|
unsigned int index,
|
|
unsigned int num,
|
|
unsigned int vring_align,
|
|
struct virtio_device *vdev,
|
|
bool weak_barriers,
|
|
bool may_reduce_num,
|
|
bool context,
|
|
bool (*notify)(struct virtqueue *),
|
|
void (*callback)(struct virtqueue *),
|
|
const char *name)
|
|
{
|
|
|
|
if (virtio_has_feature(vdev, VIRTIO_F_RING_PACKED))
|
|
return vring_create_virtqueue_packed(index, num, vring_align,
|
|
vdev, weak_barriers, may_reduce_num,
|
|
context, notify, callback, name);
|
|
|
|
return vring_create_virtqueue_split(index, num, vring_align,
|
|
vdev, weak_barriers, may_reduce_num,
|
|
context, notify, callback, name);
|
|
}
|
|
EXPORT_SYMBOL_GPL(vring_create_virtqueue);
|
|
|
|
/* Only available for split ring */
|
|
struct virtqueue *vring_new_virtqueue(unsigned int index,
|
|
unsigned int num,
|
|
unsigned int vring_align,
|
|
struct virtio_device *vdev,
|
|
bool weak_barriers,
|
|
bool context,
|
|
void *pages,
|
|
bool (*notify)(struct virtqueue *vq),
|
|
void (*callback)(struct virtqueue *vq),
|
|
const char *name)
|
|
{
|
|
struct vring vring;
|
|
|
|
if (virtio_has_feature(vdev, VIRTIO_F_RING_PACKED))
|
|
return NULL;
|
|
|
|
vring_init(&vring, num, pages, vring_align);
|
|
return __vring_new_virtqueue(index, vring, vdev, weak_barriers, context,
|
|
notify, callback, name);
|
|
}
|
|
EXPORT_SYMBOL_GPL(vring_new_virtqueue);
|
|
|
|
void vring_del_virtqueue(struct virtqueue *_vq)
|
|
{
|
|
struct vring_virtqueue *vq = to_vvq(_vq);
|
|
|
|
if (vq->we_own_ring) {
|
|
if (vq->packed_ring) {
|
|
vring_free_queue(vq->vq.vdev,
|
|
vq->packed.ring_size_in_bytes,
|
|
vq->packed.vring.desc,
|
|
vq->packed.ring_dma_addr);
|
|
|
|
vring_free_queue(vq->vq.vdev,
|
|
vq->packed.event_size_in_bytes,
|
|
vq->packed.vring.driver,
|
|
vq->packed.driver_event_dma_addr);
|
|
|
|
vring_free_queue(vq->vq.vdev,
|
|
vq->packed.event_size_in_bytes,
|
|
vq->packed.vring.device,
|
|
vq->packed.device_event_dma_addr);
|
|
|
|
kfree(vq->packed.desc_state);
|
|
kfree(vq->packed.desc_extra);
|
|
} else {
|
|
vring_free_queue(vq->vq.vdev,
|
|
vq->split.queue_size_in_bytes,
|
|
vq->split.vring.desc,
|
|
vq->split.queue_dma_addr);
|
|
|
|
kfree(vq->split.desc_state);
|
|
}
|
|
}
|
|
list_del(&_vq->list);
|
|
kfree(vq);
|
|
}
|
|
EXPORT_SYMBOL_GPL(vring_del_virtqueue);
|
|
|
|
/* Manipulates transport-specific feature bits. */
|
|
void vring_transport_features(struct virtio_device *vdev)
|
|
{
|
|
unsigned int i;
|
|
|
|
for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++) {
|
|
switch (i) {
|
|
case VIRTIO_RING_F_INDIRECT_DESC:
|
|
break;
|
|
case VIRTIO_RING_F_EVENT_IDX:
|
|
break;
|
|
case VIRTIO_F_VERSION_1:
|
|
break;
|
|
case VIRTIO_F_IOMMU_PLATFORM:
|
|
break;
|
|
case VIRTIO_F_RING_PACKED:
|
|
break;
|
|
case VIRTIO_F_ORDER_PLATFORM:
|
|
break;
|
|
default:
|
|
/* We don't understand this bit. */
|
|
__virtio_clear_bit(vdev, i);
|
|
}
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(vring_transport_features);
|
|
|
|
/**
|
|
* virtqueue_get_vring_size - return the size of the virtqueue's vring
|
|
* @_vq: the struct virtqueue containing the vring of interest.
|
|
*
|
|
* Returns the size of the vring. This is mainly used for boasting to
|
|
* userspace. Unlike other operations, this need not be serialized.
|
|
*/
|
|
unsigned int virtqueue_get_vring_size(struct virtqueue *_vq)
|
|
{
|
|
|
|
struct vring_virtqueue *vq = to_vvq(_vq);
|
|
|
|
return vq->packed_ring ? vq->packed.vring.num : vq->split.vring.num;
|
|
}
|
|
EXPORT_SYMBOL_GPL(virtqueue_get_vring_size);
|
|
|
|
bool virtqueue_is_broken(struct virtqueue *_vq)
|
|
{
|
|
struct vring_virtqueue *vq = to_vvq(_vq);
|
|
|
|
return vq->broken;
|
|
}
|
|
EXPORT_SYMBOL_GPL(virtqueue_is_broken);
|
|
|
|
/*
|
|
* This should prevent the device from being used, allowing drivers to
|
|
* recover. You may need to grab appropriate locks to flush.
|
|
*/
|
|
void virtio_break_device(struct virtio_device *dev)
|
|
{
|
|
struct virtqueue *_vq;
|
|
|
|
list_for_each_entry(_vq, &dev->vqs, list) {
|
|
struct vring_virtqueue *vq = to_vvq(_vq);
|
|
vq->broken = true;
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(virtio_break_device);
|
|
|
|
dma_addr_t virtqueue_get_desc_addr(struct virtqueue *_vq)
|
|
{
|
|
struct vring_virtqueue *vq = to_vvq(_vq);
|
|
|
|
BUG_ON(!vq->we_own_ring);
|
|
|
|
if (vq->packed_ring)
|
|
return vq->packed.ring_dma_addr;
|
|
|
|
return vq->split.queue_dma_addr;
|
|
}
|
|
EXPORT_SYMBOL_GPL(virtqueue_get_desc_addr);
|
|
|
|
dma_addr_t virtqueue_get_avail_addr(struct virtqueue *_vq)
|
|
{
|
|
struct vring_virtqueue *vq = to_vvq(_vq);
|
|
|
|
BUG_ON(!vq->we_own_ring);
|
|
|
|
if (vq->packed_ring)
|
|
return vq->packed.driver_event_dma_addr;
|
|
|
|
return vq->split.queue_dma_addr +
|
|
((char *)vq->split.vring.avail - (char *)vq->split.vring.desc);
|
|
}
|
|
EXPORT_SYMBOL_GPL(virtqueue_get_avail_addr);
|
|
|
|
dma_addr_t virtqueue_get_used_addr(struct virtqueue *_vq)
|
|
{
|
|
struct vring_virtqueue *vq = to_vvq(_vq);
|
|
|
|
BUG_ON(!vq->we_own_ring);
|
|
|
|
if (vq->packed_ring)
|
|
return vq->packed.device_event_dma_addr;
|
|
|
|
return vq->split.queue_dma_addr +
|
|
((char *)vq->split.vring.used - (char *)vq->split.vring.desc);
|
|
}
|
|
EXPORT_SYMBOL_GPL(virtqueue_get_used_addr);
|
|
|
|
/* Only available for split ring */
|
|
const struct vring *virtqueue_get_vring(struct virtqueue *vq)
|
|
{
|
|
return &to_vvq(vq)->split.vring;
|
|
}
|
|
EXPORT_SYMBOL_GPL(virtqueue_get_vring);
|
|
|
|
MODULE_LICENSE("GPL");
|