Commit 459cfb80a7 for qemu.org

commit 459cfb80a77f38b521a887338d05e82a9ea2f0fc
Author: Eugenio Pérez <eperezma@redhat.com>
Date:   Mon Dec 1 13:51:49 2025 +0100

    vhost: accept indirect descriptors in shadow virtqueue

    The device is not able to generate indirect descriptors by itself, only
    the driver can do it.  And SVQ is already able to handle them by reusing
    VirtQueue struct.

    Shadow VirtQueue just transform the indirect descriptors to chained
    buffers.  This way we don't need to map a new buffer for the indirect
    table and handle its exhaustion etc.  As they are only used in control
    plane and HW devices don't like indirect, we should not see significant
    downsides with these.

    Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
    --

    Tested functionally by forwarding the CVQ descriptors.

    Acked-by: Jason Wang <jasowang@redhat.com>
    Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
    Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
    Message-Id: <20251201125149.2151026-1-eperezma@redhat.com>

diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c
index 2481d49345..6242aeb69c 100644
--- a/hw/virtio/vhost-shadow-virtqueue.c
+++ b/hw/virtio/vhost-shadow-virtqueue.c
@@ -34,6 +34,7 @@ bool vhost_svq_valid_features(uint64_t features, Error **errp)
         switch (b) {
         case VIRTIO_F_ANY_LAYOUT:
         case VIRTIO_RING_F_EVENT_IDX:
+        case VIRTIO_RING_F_INDIRECT_DESC:
             continue;

         case VIRTIO_F_ACCESS_PLATFORM: