Patchwork virtio-blk: add msi support.

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Submitter Gerd Hoffmann
Date Aug. 12, 2009, 10:47 a.m.
Message ID <1250074044-24667-1-git-send-email-kraxel@redhat.com>
Download mbox | patch
Permalink /patch/31182/
State Superseded
Headers show

Comments

Gerd Hoffmann - Aug. 12, 2009, 10:47 a.m.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 hw/pc.c         |    4 ++++
 hw/virtio-pci.c |    8 ++++++--
 2 files changed, 10 insertions(+), 2 deletions(-)
Christoph Hellwig - Aug. 12, 2009, 9:57 p.m.
Ah nice, I was just about to start doing this.  It's worth mentioning
that this gives an about 5% speedup for workloads with small I/O sizes.
Mark McLoughlin - Sept. 7, 2009, 5:57 p.m.
On Wed, 2009-08-12 at 12:47 +0200, Gerd Hoffmann wrote:
> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
> ---
>  hw/pc.c         |    4 ++++
>  hw/virtio-pci.c |    8 ++++++--
>  2 files changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/pc.c b/hw/pc.c
> index cc6e7e8..cccb865 100644
> --- a/hw/pc.c
> +++ b/hw/pc.c
> @@ -1487,6 +1487,10 @@ static QEMUMachine pc_machine_v0_10 = {
>              .driver   = "virtio-net-pci",
>              .property = "vectors",
>              .value    = stringify(0),
> +        },{
> +            .driver   = "virtio-blk-pci",
> +            .property = "vectors",
> +            .value    = stringify(0),

This means that MSI is enabled for virtio-blk with the pc-0.11 machine
type.

Shouldn't we add a pc-0.12 machine type and disable MSI for pc-0.11?

Cheers,
Mark.
Gerd Hoffmann - Sept. 8, 2009, 6:39 a.m.
On 09/07/09 19:57, Mark McLoughlin wrote:
> On Wed, 2009-08-12 at 12:47 +0200, Gerd Hoffmann wrote:
>> Signed-off-by: Gerd Hoffmann<kraxel@redhat.com>
>> ---
>>   hw/pc.c         |    4 ++++
>>   hw/virtio-pci.c |    8 ++++++--
>>   2 files changed, 10 insertions(+), 2 deletions(-)
>>
>> diff --git a/hw/pc.c b/hw/pc.c
>> index cc6e7e8..cccb865 100644
>> --- a/hw/pc.c
>> +++ b/hw/pc.c
>> @@ -1487,6 +1487,10 @@ static QEMUMachine pc_machine_v0_10 = {
>>               .driver   = "virtio-net-pci",
>>               .property = "vectors",
>>               .value    = stringify(0),
>> +        },{
>> +            .driver   = "virtio-blk-pci",
>> +            .property = "vectors",
>> +            .value    = stringify(0),
>
> This means that MSI is enabled for virtio-blk with the pc-0.11 machine
> type.
>
> Shouldn't we add a pc-0.12 machine type and disable MSI for pc-0.11?

Either that or apply the virtio-blk msi patch to the stable-0.11 branch.

cheers,
   Gerd

Patch

diff --git a/hw/pc.c b/hw/pc.c
index cc6e7e8..cccb865 100644
--- a/hw/pc.c
+++ b/hw/pc.c
@@ -1487,6 +1487,10 @@  static QEMUMachine pc_machine_v0_10 = {
             .driver   = "virtio-net-pci",
             .property = "vectors",
             .value    = stringify(0),
+        },{
+            .driver   = "virtio-blk-pci",
+            .property = "vectors",
+            .value    = stringify(0),
         },
         { /* end of list */ }
     },
diff --git a/hw/virtio-pci.c b/hw/virtio-pci.c
index 8b57dfc..e95700a 100644
--- a/hw/virtio-pci.c
+++ b/hw/virtio-pci.c
@@ -437,10 +437,13 @@  static void virtio_blk_init_pci(PCIDevice *pci_dev)
         fprintf(stderr, "drive property not set\n");
     }
     vdev = virtio_blk_init(&pci_dev->qdev, proxy->dinfo);
+    vdev->nvectors = proxy->nvectors;
     virtio_init_pci(proxy, vdev,
                     PCI_VENDOR_ID_REDHAT_QUMRANET,
                     PCI_DEVICE_ID_VIRTIO_BLOCK,
                     proxy->class_code, 0x00);
+    /* make the actual value visible */
+    proxy->nvectors = vdev->nvectors;
 }
 
 static void virtio_console_init_pci(PCIDevice *pci_dev)
@@ -504,6 +507,7 @@  static PCIDeviceInfo virtio_info[] = {
         .qdev.props = (Property[]) {
             DEFINE_PROP_HEX32("class", VirtIOPCIProxy, class_code, 0),
             DEFINE_PROP_DRIVE("drive", VirtIOPCIProxy, dinfo),
+            DEFINE_PROP_UINT32("vectors", VirtIOPCIProxy, nvectors, 2),
             DEFINE_PROP_END_OF_LIST(),
         },
     },{
@@ -511,8 +515,8 @@  static PCIDeviceInfo virtio_info[] = {
         .qdev.size  = sizeof(VirtIOPCIProxy),
         .init       = virtio_net_init_pci,
         .qdev.props = (Property[]) {
-            DEFINE_PROP_HEX32("vectors", VirtIOPCIProxy, nvectors,
-                              NIC_NVECTORS_UNSPECIFIED),
+            DEFINE_PROP_UINT32("vectors", VirtIOPCIProxy, nvectors,
+                               NIC_NVECTORS_UNSPECIFIED),
             DEFINE_PROP_END_OF_LIST(),
         },
     },{