Patchwork [2/2] virtio-scsi: enable MSI-X support

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Submitter Paolo Bonzini
Date July 27, 2012, 12:39 p.m.
Message ID <1343392763-17308-3-git-send-email-pbonzini@redhat.com>
Download mbox | patch
Permalink /patch/173660/
State New
Headers show

Comments

Paolo Bonzini - July 27, 2012, 12:39 p.m.
While virtio-scsi does support multiqueue, the default number of
interrupt vectors is not enough to actually enable usage of
multiple queues in the driver; this is because with only 2
vectors the driver will not be able to use a separate
interrupt for each request queue.  Derive the desired number
of vectors from the number of request queues.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 hw/virtio-pci.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

Patch

diff --git a/hw/virtio-pci.c b/hw/virtio-pci.c
index 82859a5..1109467 100644
--- a/hw/virtio-pci.c
+++ b/hw/virtio-pci.c
@@ -1023,7 +1023,9 @@  static int virtio_scsi_init_pci(PCIDevice *pci_dev)
         return -EINVAL;
     }
 
-    vdev->nvectors = proxy->nvectors;
+    vdev->nvectors = proxy->nvectors == DEV_NVECTORS_UNSPECIFIED
+                                        ? proxy->scsi.num_queues + 3
+                                        : proxy->nvectors;
     virtio_init_pci(proxy, vdev);
 
     /* make the actual value visible */
@@ -1041,7 +1043,7 @@  static int virtio_scsi_exit_pci(PCIDevice *pci_dev)
 
 static Property virtio_scsi_properties[] = {
     DEFINE_PROP_BIT("ioeventfd", VirtIOPCIProxy, flags, VIRTIO_PCI_FLAG_USE_IOEVENTFD_BIT, true),
-    DEFINE_PROP_UINT32("vectors", VirtIOPCIProxy, nvectors, 2),
+    DEFINE_PROP_UINT32("vectors", VirtIOPCIProxy, nvectors, DEV_NVECTORS_UNSPECIFIED),
     DEFINE_VIRTIO_SCSI_PROPERTIES(VirtIOPCIProxy, host_features, scsi),
     DEFINE_PROP_END_OF_LIST(),
 };