On Mon, Mar 24, 2025 at 3:00 PM Sahil Siddiq <icegambi...@gmail.com> wrote:
>
> Allocate memory for the packed vq format and map them to the vdpa device.
>
> Since "struct vring" and "struct vring_packed's vring" both have the same
> memory layout, the implementation in SVQ start and SVQ stop should not
> differ based on the vq's format.
>
> Also initialize flags, counters and indices for packed vqs before they
> are utilized.
>
> Signed-off-by: Sahil Siddiq <sahil...@proton.me>
Acked-by: Eugenio Pérez <epere...@redhat.com>
> ---
> Changes from v4 -> v5:
> - vhost-shadow-virtqueue.c:
> (vhost_svq_start): Initialize variables used by packed vring.
>
> hw/virtio/vhost-shadow-virtqueue.c | 52 +++++++++++++++++++++---------
> hw/virtio/vhost-shadow-virtqueue.h | 1 +
> hw/virtio/vhost-vdpa.c | 37 +++++++++++++++++----
> 3 files changed, 69 insertions(+), 21 deletions(-)
>
> diff --git a/hw/virtio/vhost-shadow-virtqueue.c
> b/hw/virtio/vhost-shadow-virtqueue.c
> index 6e16cd4bdf..126957231d 100644
> --- a/hw/virtio/vhost-shadow-virtqueue.c
> +++ b/hw/virtio/vhost-shadow-virtqueue.c
> @@ -707,19 +707,33 @@ void vhost_svq_get_vring_addr(const
> VhostShadowVirtqueue *svq,
> addr->used_user_addr = (uint64_t)(uintptr_t)svq->vring.used;
> }
>
> -size_t vhost_svq_driver_area_size(const VhostShadowVirtqueue *svq)
> +size_t vhost_svq_descriptor_area_size(const VhostShadowVirtqueue *svq)
> {
> size_t desc_size = sizeof(vring_desc_t) * svq->vring.num;
> - size_t avail_size = offsetof(vring_avail_t, ring[svq->vring.num]) +
> -
> sizeof(uint16_t);
> + return ROUND_UP(desc_size, qemu_real_host_page_size());
> +}
>
> - return ROUND_UP(desc_size + avail_size, qemu_real_host_page_size());
> +size_t vhost_svq_driver_area_size(const VhostShadowVirtqueue *svq)
> +{
> + size_t avail_size;
> + if (svq->is_packed) {
> + avail_size = sizeof(uint32_t);
> + } else {
> + avail_size = offsetof(vring_avail_t, ring[svq->vring.num]) +
> +
> sizeof(uint16_t);
> + }
> + return ROUND_UP(avail_size, qemu_real_host_page_size());
> }
>
> size_t vhost_svq_device_area_size(const VhostShadowVirtqueue *svq)
> {
> - size_t used_size = offsetof(vring_used_t, ring[svq->vring.num]) +
> -
> sizeof(uint16_t);
> + size_t used_size;
> + if (svq->is_packed) {
> + used_size = sizeof(uint32_t);
> + } else {
> + used_size = offsetof(vring_used_t, ring[svq->vring.num]) +
> + sizeof(uint16_t);
> + }
> return ROUND_UP(used_size, qemu_real_host_page_size());
> }
>
> @@ -764,8 +778,6 @@ void vhost_svq_set_svq_kick_fd(VhostShadowVirtqueue *svq,
> int svq_kick_fd)
> void vhost_svq_start(VhostShadowVirtqueue *svq, VirtIODevice *vdev,
> VirtQueue *vq, VhostIOVATree *iova_tree)
> {
> - size_t desc_size;
> -
> event_notifier_set_handler(&svq->hdev_call, vhost_svq_handle_call);
> svq->next_guest_avail_elem = NULL;
> svq->shadow_avail_idx = 0;
> @@ -774,20 +786,29 @@ void vhost_svq_start(VhostShadowVirtqueue *svq,
> VirtIODevice *vdev,
> svq->vdev = vdev;
> svq->vq = vq;
> svq->iova_tree = iova_tree;
> + svq->is_packed = virtio_vdev_has_feature(svq->vdev,
> VIRTIO_F_RING_PACKED);
> +
> + if (svq->is_packed) {
> + svq->vring_packed.avail_wrap_counter = 1;
> + svq->vring_packed.next_avail_idx = 0;
> + svq->vring_packed.avail_used_flags = 1 << VRING_PACKED_DESC_F_AVAIL;
> + svq->last_used_idx = 0 | (1 << VRING_PACKED_EVENT_F_WRAP_CTR);
> + }
>
> svq->vring.num = virtio_queue_get_num(vdev, virtio_get_queue_index(vq));
> svq->num_free = svq->vring.num;
> - svq->vring.desc = mmap(NULL, vhost_svq_driver_area_size(svq),
> + svq->vring.desc = mmap(NULL, vhost_svq_descriptor_area_size(svq),
> PROT_READ | PROT_WRITE, MAP_SHARED |
> MAP_ANONYMOUS,
> -1, 0);
> - desc_size = sizeof(vring_desc_t) * svq->vring.num;
> - svq->vring.avail = (void *)((char *)svq->vring.desc + desc_size);
> + svq->vring.avail = mmap(NULL, vhost_svq_driver_area_size(svq),
> + PROT_READ | PROT_WRITE, MAP_SHARED |
> MAP_ANONYMOUS,
> + -1, 0);
> svq->vring.used = mmap(NULL, vhost_svq_device_area_size(svq),
> PROT_READ | PROT_WRITE, MAP_SHARED |
> MAP_ANONYMOUS,
> -1, 0);
> - svq->desc_state = g_new0(SVQDescState, svq->vring.num);
> - svq->desc_next = g_new0(uint16_t, svq->vring.num);
> - for (unsigned i = 0; i < svq->vring.num - 1; i++) {
> + svq->desc_state = g_new0(SVQDescState, svq->num_free);
> + svq->desc_next = g_new0(uint16_t, svq->num_free);
> + for (unsigned i = 0; i < svq->num_free - 1; i++) {
> svq->desc_next[i] = i + 1;
> }
> }
> @@ -827,7 +848,8 @@ void vhost_svq_stop(VhostShadowVirtqueue *svq)
> svq->vq = NULL;
> g_free(svq->desc_next);
> g_free(svq->desc_state);
> - munmap(svq->vring.desc, vhost_svq_driver_area_size(svq));
> + munmap(svq->vring.desc, vhost_svq_descriptor_area_size(svq));
> + munmap(svq->vring.avail, vhost_svq_driver_area_size(svq));
> munmap(svq->vring.used, vhost_svq_device_area_size(svq));
> event_notifier_set_handler(&svq->hdev_call, NULL);
> }
> diff --git a/hw/virtio/vhost-shadow-virtqueue.h
> b/hw/virtio/vhost-shadow-virtqueue.h
> index 5f7699da9d..12c6ea8be2 100644
> --- a/hw/virtio/vhost-shadow-virtqueue.h
> +++ b/hw/virtio/vhost-shadow-virtqueue.h
> @@ -152,6 +152,7 @@ void vhost_svq_set_svq_kick_fd(VhostShadowVirtqueue *svq,
> int svq_kick_fd);
> void vhost_svq_set_svq_call_fd(VhostShadowVirtqueue *svq, int call_fd);
> void vhost_svq_get_vring_addr(const VhostShadowVirtqueue *svq,
> struct vhost_vring_addr *addr);
> +size_t vhost_svq_descriptor_area_size(const VhostShadowVirtqueue *svq);
> size_t vhost_svq_driver_area_size(const VhostShadowVirtqueue *svq);
> size_t vhost_svq_device_area_size(const VhostShadowVirtqueue *svq);
>
> diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
> index 7efbde3d4c..58c8931d89 100644
> --- a/hw/virtio/vhost-vdpa.c
> +++ b/hw/virtio/vhost-vdpa.c
> @@ -1137,6 +1137,8 @@ static void vhost_vdpa_svq_unmap_rings(struct vhost_dev
> *dev,
>
> vhost_vdpa_svq_unmap_ring(v, svq_addr.desc_user_addr);
>
> + vhost_vdpa_svq_unmap_ring(v, svq_addr.avail_user_addr);
> +
> vhost_vdpa_svq_unmap_ring(v, svq_addr.used_user_addr);
> }
>
> @@ -1191,38 +1193,61 @@ static bool vhost_vdpa_svq_map_rings(struct vhost_dev
> *dev,
> Error **errp)
> {
> ERRP_GUARD();
> - DMAMap device_region, driver_region;
> + DMAMap descriptor_region, device_region, driver_region;
> struct vhost_vring_addr svq_addr;
> struct vhost_vdpa *v = dev->opaque;
> + size_t descriptor_size = vhost_svq_descriptor_area_size(svq);
> size_t device_size = vhost_svq_device_area_size(svq);
> size_t driver_size = vhost_svq_driver_area_size(svq);
> - size_t avail_offset;
> bool ok;
>
> vhost_svq_get_vring_addr(svq, &svq_addr);
>
> + descriptor_region = (DMAMap) {
> + .translated_addr = svq_addr.desc_user_addr,
> + .size = descriptor_size - 1,
> + .perm = IOMMU_RO,
> + };
> + if (svq->is_packed) {
> + descriptor_region.perm = IOMMU_RW;
> + }
> +
> + ok = vhost_vdpa_svq_map_ring(v, &descriptor_region,
> svq_addr.desc_user_addr,
> + errp);
> + if (unlikely(!ok)) {
> + error_prepend(errp, "Cannot create vq descriptor region: ");
> + return false;
> + }
> + addr->desc_user_addr = descriptor_region.iova;
> +
> driver_region = (DMAMap) {
> + .translated_addr = svq_addr.avail_user_addr,
> .size = driver_size - 1,
> .perm = IOMMU_RO,
> };
> - ok = vhost_vdpa_svq_map_ring(v, &driver_region, svq_addr.desc_user_addr,
> + ok = vhost_vdpa_svq_map_ring(v, &driver_region, svq_addr.avail_user_addr,
> errp);
> if (unlikely(!ok)) {
> error_prepend(errp, "Cannot create vq driver region: ");
> + vhost_vdpa_svq_unmap_ring(v, descriptor_region.translated_addr);
> return false;
> }
> - addr->desc_user_addr = driver_region.iova;
> - avail_offset = svq_addr.avail_user_addr - svq_addr.desc_user_addr;
> - addr->avail_user_addr = driver_region.iova + avail_offset;
> + addr->avail_user_addr = driver_region.iova;
>
> device_region = (DMAMap) {
> + .translated_addr = svq_addr.used_user_addr,
> .size = device_size - 1,
> .perm = IOMMU_RW,
> };
> + if (svq->is_packed) {
> + device_region.perm = IOMMU_WO;
> + }
> +
> ok = vhost_vdpa_svq_map_ring(v, &device_region, svq_addr.used_user_addr,
> errp);
> if (unlikely(!ok)) {
> error_prepend(errp, "Cannot create vq device region: ");
> + vhost_vdpa_svq_unmap_ring(v, descriptor_region.translated_addr);
> vhost_vdpa_svq_unmap_ring(v, driver_region.translated_addr);
> }
> addr->used_user_addr = device_region.iova;
> --
> 2.48.1
>
