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82af8ce84e
This implements optional MSI-X support in virtio_pci. MSI-X is used whenever the host supports at least 2 MSI-X vectors: 1 for configuration changes and 1 for virtqueues. Per-virtqueue vectors are allocated if enough vectors available. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Acked-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (+ whitespace, style)
73 lines
2.2 KiB
C
73 lines
2.2 KiB
C
/*
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* Virtio PCI driver
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*
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* This module allows virtio devices to be used over a virtual PCI device.
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* This can be used with QEMU based VMMs like KVM or Xen.
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*
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* Copyright IBM Corp. 2007
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*
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* Authors:
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* Anthony Liguori <aliguori@us.ibm.com>
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*
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* This header is BSD licensed so anyone can use the definitions to implement
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* compatible drivers/servers.
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*/
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#ifndef _LINUX_VIRTIO_PCI_H
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#define _LINUX_VIRTIO_PCI_H
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#include <linux/virtio_config.h>
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/* A 32-bit r/o bitmask of the features supported by the host */
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#define VIRTIO_PCI_HOST_FEATURES 0
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/* A 32-bit r/w bitmask of features activated by the guest */
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#define VIRTIO_PCI_GUEST_FEATURES 4
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/* A 32-bit r/w PFN for the currently selected queue */
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#define VIRTIO_PCI_QUEUE_PFN 8
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/* A 16-bit r/o queue size for the currently selected queue */
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#define VIRTIO_PCI_QUEUE_NUM 12
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/* A 16-bit r/w queue selector */
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#define VIRTIO_PCI_QUEUE_SEL 14
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/* A 16-bit r/w queue notifier */
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#define VIRTIO_PCI_QUEUE_NOTIFY 16
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/* An 8-bit device status register. */
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#define VIRTIO_PCI_STATUS 18
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/* An 8-bit r/o interrupt status register. Reading the value will return the
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* current contents of the ISR and will also clear it. This is effectively
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* a read-and-acknowledge. */
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#define VIRTIO_PCI_ISR 19
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/* The bit of the ISR which indicates a device configuration change. */
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#define VIRTIO_PCI_ISR_CONFIG 0x2
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/* MSI-X registers: only enabled if MSI-X is enabled. */
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/* A 16-bit vector for configuration changes. */
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#define VIRTIO_MSI_CONFIG_VECTOR 20
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/* A 16-bit vector for selected queue notifications. */
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#define VIRTIO_MSI_QUEUE_VECTOR 22
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/* Vector value used to disable MSI for queue */
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#define VIRTIO_MSI_NO_VECTOR 0xffff
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/* The remaining space is defined by each driver as the per-driver
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* configuration space */
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#define VIRTIO_PCI_CONFIG(dev) ((dev)->msix_enabled ? 24 : 20)
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/* Virtio ABI version, this must match exactly */
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#define VIRTIO_PCI_ABI_VERSION 0
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/* How many bits to shift physical queue address written to QUEUE_PFN.
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* 12 is historical, and due to x86 page size. */
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#define VIRTIO_PCI_QUEUE_ADDR_SHIFT 12
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/* The alignment to use between consumer and producer parts of vring.
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* x86 pagesize again. */
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#define VIRTIO_PCI_VRING_ALIGN 4096
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#endif
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