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46f9c2b925
Currently a host kick error is silently ignored and not reflected in the virtqueue of a particular virtio device. Changing the notify API for guest->host notification seems to be one prerequisite in order to be able to handle such errors in the context where the kick is triggered. This patch changes the notify API. The notify function must return a bool return value. It returns false if the host notification failed. Signed-off-by: Heinz Graalfs <graalfs@linux.vnet.ibm.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
83 lines
1.9 KiB
C
83 lines
1.9 KiB
C
#ifndef _LINUX_VIRTIO_RING_H
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#define _LINUX_VIRTIO_RING_H
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#include <asm/barrier.h>
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#include <linux/irqreturn.h>
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#include <uapi/linux/virtio_ring.h>
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/*
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* Barriers in virtio are tricky. Non-SMP virtio guests can't assume
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* they're not on an SMP host system, so they need to assume real
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* barriers. Non-SMP virtio hosts could skip the barriers, but does
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* anyone care?
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*
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* For virtio_pci on SMP, we don't need to order with respect to MMIO
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* accesses through relaxed memory I/O windows, so smp_mb() et al are
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* sufficient.
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*
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* For using virtio to talk to real devices (eg. other heterogeneous
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* CPUs) we do need real barriers. In theory, we could be using both
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* kinds of virtio, so it's a runtime decision, and the branch is
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* actually quite cheap.
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*/
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#ifdef CONFIG_SMP
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static inline void virtio_mb(bool weak_barriers)
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{
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if (weak_barriers)
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smp_mb();
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else
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mb();
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}
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static inline void virtio_rmb(bool weak_barriers)
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{
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if (weak_barriers)
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smp_rmb();
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else
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rmb();
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}
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static inline void virtio_wmb(bool weak_barriers)
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{
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if (weak_barriers)
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smp_wmb();
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else
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wmb();
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}
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#else
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static inline void virtio_mb(bool weak_barriers)
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{
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mb();
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}
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static inline void virtio_rmb(bool weak_barriers)
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{
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rmb();
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}
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static inline void virtio_wmb(bool weak_barriers)
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{
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wmb();
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}
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#endif
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struct virtio_device;
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struct virtqueue;
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struct virtqueue *vring_new_virtqueue(unsigned int index,
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unsigned int num,
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unsigned int vring_align,
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struct virtio_device *vdev,
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bool weak_barriers,
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void *pages,
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bool (*notify)(struct virtqueue *vq),
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void (*callback)(struct virtqueue *vq),
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const char *name);
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void vring_del_virtqueue(struct virtqueue *vq);
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/* Filter out transport-specific feature bits. */
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void vring_transport_features(struct virtio_device *vdev);
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irqreturn_t vring_interrupt(int irq, void *_vq);
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#endif /* _LINUX_VIRTIO_RING_H */
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