Re: [Qemu-devel] [PATCH v2] virtio-blk: enable multiple vectors when using multiple I/O queues

[Paolo Bonzini <pbonzini@redhat.com>]

On 06/02/2018 02:35, Changpeng Liu wrote:
> Currently virtio-pci driver hardcoded 2 vectors for virtio-blk device,
> for multiple I/O queues scenario, all the I/O queues will share one
> interrupt vector, while here, enable multiple vectors according to
> the number of I/O queues.
> 
> Signed-off-by: Changpeng Liu <changpeng.liu@intel.com>
> ---
>  hw/virtio/virtio-pci.c | 14 ++++++++++++--
>  include/hw/compat.h    |  8 ++++++++
>  2 files changed, 20 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
> index 9ae10f0..84a7674 100644
> --- a/hw/virtio/virtio-pci.c
> +++ b/hw/virtio/virtio-pci.c
> @@ -1932,7 +1932,8 @@ static Property virtio_blk_pci_properties[] = {
>      DEFINE_PROP_UINT32("class", VirtIOPCIProxy, class_code, 0),
>      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_PROP_END_OF_LIST(),
>  };
>  
> @@ -1941,6 +1942,10 @@ static void virtio_blk_pci_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
>      VirtIOBlkPCI *dev = VIRTIO_BLK_PCI(vpci_dev);
>      DeviceState *vdev = DEVICE(&dev->vdev);
>  
> +    if (vpci_dev->nvectors == DEV_NVECTORS_UNSPECIFIED) {
> +        vpci_dev->nvectors = dev->vdev.conf.num_queues + 1;
> +    }
> +
>      qdev_set_parent_bus(vdev, BUS(&vpci_dev->bus));
>      object_property_set_bool(OBJECT(vdev), true, "realized", errp);
>  }
> @@ -1983,7 +1988,8 @@ static const TypeInfo virtio_blk_pci_info = {
>  
>  static Property vhost_user_blk_pci_properties[] = {
>      DEFINE_PROP_UINT32("class", VirtIOPCIProxy, class_code, 0),
> -    DEFINE_PROP_UINT32("vectors", VirtIOPCIProxy, nvectors, 2),
> +    DEFINE_PROP_UINT32("vectors", VirtIOPCIProxy, nvectors,
> +                       DEV_NVECTORS_UNSPECIFIED),
>      DEFINE_PROP_END_OF_LIST(),
>  };
>  
> @@ -1992,6 +1998,10 @@ static void vhost_user_blk_pci_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
>      VHostUserBlkPCI *dev = VHOST_USER_BLK_PCI(vpci_dev);
>      DeviceState *vdev = DEVICE(&dev->vdev);
>  
> +    if (vpci_dev->nvectors == DEV_NVECTORS_UNSPECIFIED) {
> +        vpci_dev->nvectors = dev->vdev.num_queues + 1;
> +    }
> +
>      qdev_set_parent_bus(vdev, BUS(&vpci_dev->bus));
>      object_property_set_bool(OBJECT(vdev), true, "realized", errp);
>  }
> diff --git a/include/hw/compat.h b/include/hw/compat.h
> index 7f31850..bc9e3a6 100644
> --- a/include/hw/compat.h
> +++ b/include/hw/compat.h
> @@ -6,6 +6,14 @@
>          .driver   = "hpet",\
>          .property = "hpet-offset-saved",\
>          .value    = "false",\
> +    },{\
> +        .driver   = "virtio-blk-pci",\
> +        .property = "vectors",\
> +        .value    = "2",\
> +    },{\
> +        .driver   = "vhost-user-blk-pci",\
> +        .property = "vectors",\
> +        .value    = "2",\
>      },
>  
>  #define HW_COMPAT_2_10 \
> 

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>