On Wed, Jul 19, 2023 at 9:54 AM Hawkins Jiawei <yin31...@gmail.com> wrote:
>
> Next patches in this series will delay the polling
> and checking of buffers until either the SVQ is
> full or control commands shadow buffers are full,
> no longer perform an immediate poll and check of
> the device's used buffers for each CVQ state load command.
>
> To achieve this, this patch exposes
> vhost_svq_available_slots() and introduces a helper function,
> allowing QEMU to know whether the SVQ is full.
>
> Signed-off-by: Hawkins Jiawei <yin31...@gmail.com>
Acked-by: Eugenio Pérez <epere...@redhat.com>
> ---
> hw/virtio/vhost-shadow-virtqueue.c | 2 +-
> hw/virtio/vhost-shadow-virtqueue.h | 1 +
> net/vhost-vdpa.c | 9 +++++++++
> 3 files changed, 11 insertions(+), 1 deletion(-)
>
> diff --git a/hw/virtio/vhost-shadow-virtqueue.c
> b/hw/virtio/vhost-shadow-virtqueue.c
> index e731b1d2ea..fc5f408f77 100644
> --- a/hw/virtio/vhost-shadow-virtqueue.c
> +++ b/hw/virtio/vhost-shadow-virtqueue.c
> @@ -66,7 +66,7 @@ bool vhost_svq_valid_features(uint64_t features, Error
> **errp)
> *
> * @svq: The svq
> */
> -static uint16_t vhost_svq_available_slots(const VhostShadowVirtqueue *svq)
> +uint16_t vhost_svq_available_slots(const VhostShadowVirtqueue *svq)
> {
> return svq->num_free;
> }
> diff --git a/hw/virtio/vhost-shadow-virtqueue.h
> b/hw/virtio/vhost-shadow-virtqueue.h
> index 5bce67837b..19c842a15b 100644
> --- a/hw/virtio/vhost-shadow-virtqueue.h
> +++ b/hw/virtio/vhost-shadow-virtqueue.h
> @@ -114,6 +114,7 @@ typedef struct VhostShadowVirtqueue {
>
> bool vhost_svq_valid_features(uint64_t features, Error **errp);
>
> +uint16_t vhost_svq_available_slots(const VhostShadowVirtqueue *svq);
> void vhost_svq_push_elem(VhostShadowVirtqueue *svq,
> const VirtQueueElement *elem, uint32_t len);
> int vhost_svq_add(VhostShadowVirtqueue *svq, const struct iovec *out_sg,
> diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
> index 6b16c8ece0..dd71008e08 100644
> --- a/net/vhost-vdpa.c
> +++ b/net/vhost-vdpa.c
> @@ -620,6 +620,13 @@ static ssize_t vhost_vdpa_net_cvq_add(VhostVDPAState *s,
> return vhost_svq_poll(svq, 1);
> }
>
> +/* Convenience wrapper to get number of available SVQ descriptors */
> +static uint16_t vhost_vdpa_net_svq_available_slots(VhostVDPAState *s)
> +{
> + VhostShadowVirtqueue *svq = g_ptr_array_index(s->vhost_vdpa.shadow_vqs,
> 0);
> + return vhost_svq_available_slots(svq);
> +}
> +
> static ssize_t vhost_vdpa_net_load_cmd(VhostVDPAState *s, uint8_t class,
> uint8_t cmd, const struct iovec
> *data_sg,
> size_t data_num)
> @@ -640,6 +647,8 @@ static ssize_t vhost_vdpa_net_load_cmd(VhostVDPAState *s,
> uint8_t class,
> };
>
> assert(data_size < vhost_vdpa_net_cvq_cmd_page_len() - sizeof(ctrl));
> + /* Each CVQ command has one out descriptor and one in descriptor */
> + assert(vhost_vdpa_net_svq_available_slots(s) >= 2);
>
> /* pack the CVQ command header */
> memcpy(s->cvq_cmd_out_buffer, &ctrl, sizeof(ctrl));
> --
> 2.25.1
>
