From 793d6d56190397624efdcaf6e0112bd12e39c05d Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Eugenio=20P=C3=A9rez?= Date: Thu, 21 Jul 2022 15:25:01 +0200 Subject: [PATCH 02/32] vhost: Fix device's used descriptor dequeue MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit RH-Author: Eugenio Pérez RH-MergeRequest: 108: Net Control Virtqueue shadow Support RH-Commit: [2/27] b92803a0681c94c65d243dd07424522387594760 (eperezmartin/qemu-kvm) RH-Bugzilla: 1939363 RH-Acked-by: Stefano Garzarella RH-Acked-by: Cindy Lu RH-Acked-by: Laurent Vivier Bugzilla: https://bugzilla.redhat.com/1939363 Upstream Status: git://git.qemu.org/qemu.git commit 81abfa5724c9a6502d7a1d3a67c55f2a303a1170 Author: Eugenio Pérez Date: Thu May 12 19:57:43 2022 +0200 vhost: Fix device's used descriptor dequeue Only the first one of them were properly enqueued back. Fixes: 100890f7ca ("vhost: Shadow virtqueue buffers forwarding") Signed-off-by: Eugenio Pérez Message-Id: <20220512175747.142058-3-eperezma@redhat.com> Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin Signed-off-by: Eugenio Pérez --- hw/virtio/vhost-shadow-virtqueue.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c index 3155801f50..31fc50907d 100644 --- a/hw/virtio/vhost-shadow-virtqueue.c +++ b/hw/virtio/vhost-shadow-virtqueue.c @@ -334,12 +334,22 @@ static void vhost_svq_disable_notification(VhostShadowVirtqueue *svq) svq->vring.avail->flags |= cpu_to_le16(VRING_AVAIL_F_NO_INTERRUPT); } +static uint16_t vhost_svq_last_desc_of_chain(const VhostShadowVirtqueue *svq, + uint16_t num, uint16_t i) +{ + for (uint16_t j = 0; j < (num - 1); ++j) { + i = le16_to_cpu(svq->desc_next[i]); + } + + return i; +} + static VirtQueueElement *vhost_svq_get_buf(VhostShadowVirtqueue *svq, uint32_t *len) { const vring_used_t *used = svq->vring.used; vring_used_elem_t used_elem; - uint16_t last_used; + uint16_t last_used, last_used_chain, num; if (!vhost_svq_more_used(svq)) { return NULL; @@ -365,7 +375,10 @@ static VirtQueueElement *vhost_svq_get_buf(VhostShadowVirtqueue *svq, return NULL; } - svq->desc_next[used_elem.id] = svq->free_head; + num = svq->ring_id_maps[used_elem.id]->in_num + + svq->ring_id_maps[used_elem.id]->out_num; + 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; *len = used_elem.len; -- 2.31.1