On Fri, Feb 23, 2024 at 10:56:17AM +0530, Srujana Challa wrote:
> Currently, virtio_pci_queue_mem_mult function always returns 4K
> when VIRTIO_PCI_FLAG_PAGE_PER_VQ is set. But this won't
> work for vhost vdpa when host has page size other than 4K.
> This patch introduces a new property(host-page-per-vq) for vdpa
> use case to fix the same.
>
> Signed-off-by: Srujana Challa <scha...@marvell.com>
Looks good. I'd like to fail realize if both
(proxy->flags & VIRTIO_PCI_FLAG_PAGE_PER_VQ)
and
(proxy->flags & VIRTIO_PCI_FLAG_HOST_PAGE_PER_VQ)
so users do not start depending on this combination.
> ---
> v2->v3:
> - Modified property name, page-per-vdpa-vq to host-page-per-vq.
>
> v1->v2:
> - Introduced a new property to get virtqueue mem multiplier for
> vdpa use case.
>
> hw/virtio/virtio-pci.c | 10 ++++++++--
> include/hw/virtio/virtio-pci.h | 5 +++++
> 2 files changed, 13 insertions(+), 2 deletions(-)
>
> diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
> index 1a7039fb0c..f29e60830b 100644
> --- a/hw/virtio/virtio-pci.c
> +++ b/hw/virtio/virtio-pci.c
> @@ -320,8 +320,12 @@ static bool virtio_pci_ioeventfd_enabled(DeviceState *d)
>
> static inline int virtio_pci_queue_mem_mult(struct VirtIOPCIProxy *proxy)
> {
> - return (proxy->flags & VIRTIO_PCI_FLAG_PAGE_PER_VQ) ?
> - QEMU_VIRTIO_PCI_QUEUE_MEM_MULT : 4;
> + if (proxy->flags & VIRTIO_PCI_FLAG_PAGE_PER_VQ)
> + return QEMU_VIRTIO_PCI_QUEUE_MEM_MULT;
> + else if (proxy->flags & VIRTIO_PCI_FLAG_HOST_PAGE_PER_VQ)
> + return qemu_real_host_page_size();
> + else
> + return 4;
> }
>
> static int virtio_pci_ioeventfd_assign(DeviceState *d, EventNotifier
> *notifier,
> @@ -2301,6 +2305,8 @@ static Property virtio_pci_properties[] = {
> VIRTIO_PCI_FLAG_INIT_FLR_BIT, true),
> DEFINE_PROP_BIT("aer", VirtIOPCIProxy, flags,
> VIRTIO_PCI_FLAG_AER_BIT, false),
> + DEFINE_PROP_BIT("host-page-per-vq", VirtIOPCIProxy, flags,
> + VIRTIO_PCI_FLAG_HOST_PAGE_PER_VQ_BIT, false),
> DEFINE_PROP_END_OF_LIST(),
> };
>
> diff --git a/include/hw/virtio/virtio-pci.h b/include/hw/virtio/virtio-pci.h
> index 59d88018c1..81b6de4291 100644
> --- a/include/hw/virtio/virtio-pci.h
> +++ b/include/hw/virtio/virtio-pci.h
> @@ -43,6 +43,7 @@ enum {
> VIRTIO_PCI_FLAG_INIT_FLR_BIT,
> VIRTIO_PCI_FLAG_AER_BIT,
> VIRTIO_PCI_FLAG_ATS_PAGE_ALIGNED_BIT,
> + VIRTIO_PCI_FLAG_HOST_PAGE_PER_VQ_BIT,
> };
>
> /* Need to activate work-arounds for buggy guests at vmstate load. */
> @@ -89,6 +90,10 @@ enum {
> #define VIRTIO_PCI_FLAG_ATS_PAGE_ALIGNED \
> (1 << VIRTIO_PCI_FLAG_ATS_PAGE_ALIGNED_BIT)
>
> +/* page per vdpa vq flag to be used for vhost vdpa backends */
> +#define VIRTIO_PCI_FLAG_HOST_PAGE_PER_VQ \
> + (1 << VIRTIO_PCI_FLAG_HOST_PAGE_PER_VQ_BIT)
> +
> typedef struct {
> MSIMessage msg;
> int virq;
> --
> 2.25.1
