| Message ID | 20241205203430.76251-3-sahilcdq@proton.me (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Add packed virtqueue to shadow virtqueue | expand |
On Thu, Dec 5, 2024 at 9:35 PM Sahil Siddiq <icegambit91@gmail.com> wrote: > > This commit is the first in a series to add support for packed > virtqueues in vhost_shadow_virtqueue. > > This patch implements the insertion of available buffers in the > descriptor area. It takes into account descriptor chains, but does > not consider indirect descriptors. > > Also validate svq-specific features that vdpa supports. > > Signed-off-by: Sahil Siddiq <sahilcdq@proton.me> > --- > Changes v3 -> v4: > - Split commit #1 in v3 into 2 commits. > - vhost-shadow-virtqueue.c > (vhost_svq_valid_features): Add enums. > > hw/virtio/vhost-shadow-virtqueue.c | 83 +++++++++++++++++++++++++++++- > 1 file changed, 81 insertions(+), 2 deletions(-) > > diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c > index bb7cf6d5db..6eee01ab3c 100644 > --- a/hw/virtio/vhost-shadow-virtqueue.c > +++ b/hw/virtio/vhost-shadow-virtqueue.c > @@ -33,6 +33,9 @@ bool vhost_svq_valid_features(uint64_t features, Error **errp) > ++b) { > switch (b) { > case VIRTIO_F_ANY_LAYOUT: > + case VIRTIO_F_RING_PACKED: > + case VIRTIO_F_RING_RESET: > + case VIRTIO_RING_F_INDIRECT_DESC: > case VIRTIO_RING_F_EVENT_IDX: This is good, but it should be added in the last commit. Otherwise we're enabling packed vq without the code to handle it. The rest looks good to me. > continue; > > @@ -178,7 +181,78 @@ static void vhost_svq_add_split(VhostShadowVirtqueue *svq, > /* Update the avail index after write the descriptor */ > smp_wmb(); > avail->idx = cpu_to_le16(svq->shadow_avail_idx); > +} > > +/** > + * Write descriptors to SVQ packed vring > + * > + * @svq: The shadow virtqueue > + * @out_sg: The iovec to the guest > + * @out_num: Outgoing iovec length > + * @in_sg: The iovec from the guest > + * @in_num: Incoming iovec length > + * @sgs: Cache for hwaddr > + * @head: Saves current free_head > + */ > +static void vhost_svq_add_packed(VhostShadowVirtqueue *svq, > + const struct iovec *out_sg, size_t out_num, > + const struct iovec *in_sg, size_t in_num, > + hwaddr *sgs, unsigned *head) > +{ > + uint16_t id, curr, i, head_flags = 0; > + size_t num = out_num + in_num; > + unsigned n; > + > + struct vring_packed_desc *descs = svq->vring_packed.vring.desc; > + > + *head = svq->vring_packed.next_avail_idx; > + i = *head; > + id = svq->free_head; > + curr = id; > + > + /* Write descriptors to SVQ packed vring */ > + for (n = 0; n < num; n++) { > + uint16_t flags = cpu_to_le16(svq->vring_packed.avail_used_flags | > + (n < out_num ? 0 : VRING_DESC_F_WRITE) | > + (n + 1 == num ? 0 : VRING_DESC_F_NEXT)); > + if (i == *head) { > + head_flags = flags; > + } else { > + descs[i].flags = flags; > + } > + > + descs[i].addr = cpu_to_le64(sgs[n]); > + descs[i].id = id; > + if (n < out_num) { > + descs[i].len = cpu_to_le32(out_sg[n].iov_len); > + } else { > + descs[i].len = cpu_to_le32(in_sg[n - out_num].iov_len); > + } > + > + curr = cpu_to_le16(svq->desc_next[curr]); > + > + if (++i >= svq->vring_packed.vring.num) { > + i = 0; > + svq->vring_packed.avail_used_flags ^= > + 1 << VRING_PACKED_DESC_F_AVAIL | > + 1 << VRING_PACKED_DESC_F_USED; > + } > + } > + > + if (i <= *head) { > + svq->vring_packed.avail_wrap_counter ^= 1; > + } > + > + svq->vring_packed.next_avail_idx = i; > + svq->free_head = curr; > + > + /* > + * A driver MUST NOT make the first descriptor in the list > + * available before all subsequent descriptors comprising > + * the list are made available. > + */ > + smp_wmb(); > + svq->vring_packed.vring.desc[*head].flags = head_flags; > } > > static void vhost_svq_kick(VhostShadowVirtqueue *svq) > @@ -240,8 +314,13 @@ int vhost_svq_add(VhostShadowVirtqueue *svq, const struct iovec *out_sg, > return -EINVAL; > } > > - vhost_svq_add_split(svq, out_sg, out_num, in_sg, > - in_num, sgs, &qemu_head); > + if (virtio_vdev_has_feature(svq->vdev, VIRTIO_F_RING_PACKED)) { > + vhost_svq_add_packed(svq, out_sg, out_num, in_sg, > + in_num, sgs, &qemu_head); > + } else { > + vhost_svq_add_split(svq, out_sg, out_num, in_sg, > + in_num, sgs, &qemu_head); > + } > > svq->num_free -= ndescs; > svq->desc_state[qemu_head].elem = elem; > -- > 2.47.0 >
Hi, On 12/10/24 2:24 PM, Eugenio Perez Martin wrote: > On Thu, Dec 5, 2024 at 9:35 PM Sahil Siddiq <icegambit91@gmail.com> wrote: >> >> This commit is the first in a series to add support for packed >> virtqueues in vhost_shadow_virtqueue. >> >> This patch implements the insertion of available buffers in the >> descriptor area. It takes into account descriptor chains, but does >> not consider indirect descriptors. >> >> Also validate svq-specific features that vdpa supports. >> >> Signed-off-by: Sahil Siddiq <sahilcdq@proton.me> >> --- >> Changes v3 -> v4: >> - Split commit #1 in v3 into 2 commits. >> - vhost-shadow-virtqueue.c >> (vhost_svq_valid_features): Add enums. >> >> hw/virtio/vhost-shadow-virtqueue.c | 83 +++++++++++++++++++++++++++++- >> 1 file changed, 81 insertions(+), 2 deletions(-) >> >> diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c >> index bb7cf6d5db..6eee01ab3c 100644 >> --- a/hw/virtio/vhost-shadow-virtqueue.c >> +++ b/hw/virtio/vhost-shadow-virtqueue.c >> @@ -33,6 +33,9 @@ bool vhost_svq_valid_features(uint64_t features, Error **errp) >> ++b) { >> switch (b) { >> case VIRTIO_F_ANY_LAYOUT: >> + case VIRTIO_F_RING_PACKED: >> + case VIRTIO_F_RING_RESET: >> + case VIRTIO_RING_F_INDIRECT_DESC: >> case VIRTIO_RING_F_EVENT_IDX: > > This is good, but it should be added in the last commit. Otherwise > we're enabling packed vq without the code to handle it. > > The rest looks good to me. > Got it. I'll make this change before sending the next patch series. Thanks, Sahil
diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c index bb7cf6d5db..6eee01ab3c 100644 --- a/hw/virtio/vhost-shadow-virtqueue.c +++ b/hw/virtio/vhost-shadow-virtqueue.c @@ -33,6 +33,9 @@ bool vhost_svq_valid_features(uint64_t features, Error **errp) ++b) { switch (b) { case VIRTIO_F_ANY_LAYOUT: + case VIRTIO_F_RING_PACKED: + case VIRTIO_F_RING_RESET: + case VIRTIO_RING_F_INDIRECT_DESC: case VIRTIO_RING_F_EVENT_IDX: continue; @@ -178,7 +181,78 @@ static void vhost_svq_add_split(VhostShadowVirtqueue *svq, /* Update the avail index after write the descriptor */ smp_wmb(); avail->idx = cpu_to_le16(svq->shadow_avail_idx); +} +/** + * Write descriptors to SVQ packed vring + * + * @svq: The shadow virtqueue + * @out_sg: The iovec to the guest + * @out_num: Outgoing iovec length + * @in_sg: The iovec from the guest + * @in_num: Incoming iovec length + * @sgs: Cache for hwaddr + * @head: Saves current free_head + */ +static void vhost_svq_add_packed(VhostShadowVirtqueue *svq, + const struct iovec *out_sg, size_t out_num, + const struct iovec *in_sg, size_t in_num, + hwaddr *sgs, unsigned *head) +{ + uint16_t id, curr, i, head_flags = 0; + size_t num = out_num + in_num; + unsigned n; + + struct vring_packed_desc *descs = svq->vring_packed.vring.desc; + + *head = svq->vring_packed.next_avail_idx; + i = *head; + id = svq->free_head; + curr = id; + + /* Write descriptors to SVQ packed vring */ + for (n = 0; n < num; n++) { + uint16_t flags = cpu_to_le16(svq->vring_packed.avail_used_flags | + (n < out_num ? 0 : VRING_DESC_F_WRITE) | + (n + 1 == num ? 0 : VRING_DESC_F_NEXT)); + if (i == *head) { + head_flags = flags; + } else { + descs[i].flags = flags; + } + + descs[i].addr = cpu_to_le64(sgs[n]); + descs[i].id = id; + if (n < out_num) { + descs[i].len = cpu_to_le32(out_sg[n].iov_len); + } else { + descs[i].len = cpu_to_le32(in_sg[n - out_num].iov_len); + } + + curr = cpu_to_le16(svq->desc_next[curr]); + + if (++i >= svq->vring_packed.vring.num) { + i = 0; + svq->vring_packed.avail_used_flags ^= + 1 << VRING_PACKED_DESC_F_AVAIL | + 1 << VRING_PACKED_DESC_F_USED; + } + } + + if (i <= *head) { + svq->vring_packed.avail_wrap_counter ^= 1; + } + + svq->vring_packed.next_avail_idx = i; + svq->free_head = curr; + + /* + * A driver MUST NOT make the first descriptor in the list + * available before all subsequent descriptors comprising + * the list are made available. + */ + smp_wmb(); + svq->vring_packed.vring.desc[*head].flags = head_flags; } static void vhost_svq_kick(VhostShadowVirtqueue *svq) @@ -240,8 +314,13 @@ int vhost_svq_add(VhostShadowVirtqueue *svq, const struct iovec *out_sg, return -EINVAL; } - vhost_svq_add_split(svq, out_sg, out_num, in_sg, - in_num, sgs, &qemu_head); + if (virtio_vdev_has_feature(svq->vdev, VIRTIO_F_RING_PACKED)) { + vhost_svq_add_packed(svq, out_sg, out_num, in_sg, + in_num, sgs, &qemu_head); + } else { + vhost_svq_add_split(svq, out_sg, out_num, in_sg, + in_num, sgs, &qemu_head); + } svq->num_free -= ndescs; svq->desc_state[qemu_head].elem = elem;
This commit is the first in a series to add support for packed virtqueues in vhost_shadow_virtqueue. This patch implements the insertion of available buffers in the descriptor area. It takes into account descriptor chains, but does not consider indirect descriptors. Also validate svq-specific features that vdpa supports. Signed-off-by: Sahil Siddiq <sahilcdq@proton.me> --- Changes v3 -> v4: - Split commit #1 in v3 into 2 commits. - vhost-shadow-virtqueue.c (vhost_svq_valid_features): Add enums. hw/virtio/vhost-shadow-virtqueue.c | 83 +++++++++++++++++++++++++++++- 1 file changed, 81 insertions(+), 2 deletions(-)