On Thu, 23 Apr 2015 14:21:48 +0800
Jason Wang <jasow...@redhat.com> wrote:
> This patch increases the maximum number of virtqueues for pci from 64
> to 513. This will allow booting a virtio-net-pci device with 256 queue
^^^
> pairs on recent Linux host (which supports up to 256 tuntap queue pairs).
>
> To keep migration compatibility, 64 was kept for legacy machine
> types. This is because qemu in fact allows guest to probe the limit of
> virtqueues through trying to set queue_sel. So for legacy machine
> type, we should make sure setting queue_sel to more than 63 won't
> make effect.
>
> Cc: Paolo Bonzini <pbonz...@redhat.com>
> Cc: Richard Henderson <r...@twiddle.net>
> Cc: Michael S. Tsirkin <m...@redhat.com>
> Cc: Alexander Graf <ag...@suse.de>
> Cc: qemu-...@nongnu.org
> Signed-off-by: Jason Wang <jasow...@redhat.com>
> ---
> hw/i386/pc_piix.c | 5 +++++
> hw/i386/pc_q35.c | 5 +++++
> hw/ppc/spapr.c | 5 +++++
> hw/virtio/virtio-pci.c | 6 +++++-
> 4 files changed, 20 insertions(+), 1 deletion(-)
>
(...)
> diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
> index 7d01500..c510cb7 100644
> --- a/hw/virtio/virtio-pci.c
> +++ b/hw/virtio/virtio-pci.c
> @@ -42,7 +42,11 @@
> * configuration space */
> #define VIRTIO_PCI_CONFIG_SIZE(dev)
> VIRTIO_PCI_CONFIG_OFF(msix_enabled(dev))
>
> -#define VIRTIO_PCI_QUEUE_MAX 64
> +/* The number was chose to be greater than both the the number of max
> + * vcpus supported by host and the number of max tuntap queues support
> + * by host and also leave some spaces for future.
> + */
> +#define VIRTIO_PCI_QUEUE_MAX 1024
^^^^
I think you need to fixup subject and patch description :)
>
> static void virtio_pci_bus_new(VirtioBusState *bus, size_t bus_size,
> VirtIOPCIProxy *dev);
