virtio_pci: optional MSI-X support

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)
This commit is contained in:
Michael S. Tsirkin
2009-05-14 13:55:41 +03:00
committed by Rusty Russell
parent 77cf524654
commit 82af8ce84e
2 changed files with 218 additions and 20 deletions

View File

@@ -47,9 +47,17 @@
/* The bit of the ISR which indicates a device configuration change. */
#define VIRTIO_PCI_ISR_CONFIG 0x2
/* MSI-X registers: only enabled if MSI-X is enabled. */
/* A 16-bit vector for configuration changes. */
#define VIRTIO_MSI_CONFIG_VECTOR 20
/* A 16-bit vector for selected queue notifications. */
#define VIRTIO_MSI_QUEUE_VECTOR 22
/* Vector value used to disable MSI for queue */
#define VIRTIO_MSI_NO_VECTOR 0xffff
/* The remaining space is defined by each driver as the per-driver
* configuration space */
#define VIRTIO_PCI_CONFIG 20
#define VIRTIO_PCI_CONFIG(dev) ((dev)->msix_enabled ? 24 : 20)
/* Virtio ABI version, this must match exactly */
#define VIRTIO_PCI_ABI_VERSION 0