From cf08dbe33683a66a79ec07b8450f9d3d27cff1c4 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Eugenio=20P=C3=A9rez?= Date: Tue, 23 Aug 2022 20:30:27 +0200 Subject: [PATCH 09/29] vhost: use SVQ element ndescs instead of opaque data for desc validation MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit RH-Author: Laurent Vivier RH-MergeRequest: 117: vDPA SVQ Multiqueue support RH-Jira: RHELX-57 RH-Acked-by: Jason Wang RH-Acked-by: Cindy Lu RH-Acked-by: Eugenio Pérez RH-Commit: [9/25] 071eb2a0db612d516d630a15a1f0fd908ed86fd3 (redhat/centos-stream/src/qemu-kvm) Since we're going to allow SVQ to add elements without the guest's knowledge and without its own VirtQueueElement, it's easier to check if an element is a valid head checking a different thing than the VirtQueueElement. Signed-off-by: Eugenio Pérez Acked-by: Jason Wang Signed-off-by: Jason Wang (cherry picked from commit 86f5f2546f03a3dfde421c715187b262e29b2848) Signed-off-by: Laurent Vivier --- hw/virtio/vhost-shadow-virtqueue.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c index a1261d4a0f..b35aeef4bd 100644 --- a/hw/virtio/vhost-shadow-virtqueue.c +++ b/hw/virtio/vhost-shadow-virtqueue.c @@ -414,7 +414,7 @@ static VirtQueueElement *vhost_svq_get_buf(VhostShadowVirtqueue *svq, return NULL; } - if (unlikely(!svq->desc_state[used_elem.id].elem)) { + if (unlikely(!svq->desc_state[used_elem.id].ndescs)) { qemu_log_mask(LOG_GUEST_ERROR, "Device %s says index %u is used, but it was not available", svq->vdev->name, used_elem.id); @@ -422,6 +422,7 @@ static VirtQueueElement *vhost_svq_get_buf(VhostShadowVirtqueue *svq, } num = svq->desc_state[used_elem.id].ndescs; + svq->desc_state[used_elem.id].ndescs = 0; last_used_chain = vhost_svq_last_desc_of_chain(svq, num, used_elem.id); svq->desc_next[last_used_chain] = svq->free_head; svq->free_head = used_elem.id; -- 2.31.1