From 06ca4cab12a4216d40c297d8a79c83a4df4dd80e Mon Sep 17 00:00:00 2001 From: Ladi Prosek Date: Wed, 5 Oct 2016 17:22:24 +0200 Subject: [PATCH 2/8] virtio: introduce virtqueue_discard() RH-Author: Ladi Prosek Message-id: <1475666548-9186-3-git-send-email-lprosek@redhat.com> Patchwork-id: 72481 O-Subject: [RHEL-7.4 qemu-kvm v2 PATCH 2/6] virtio: introduce virtqueue_discard() Bugzilla: 1377968 RH-Acked-by: Paolo Bonzini RH-Acked-by: Michael S. Tsirkin RH-Acked-by: Stefan Hajnoczi From: Jason Wang This patch introduces virtqueue_discard() to discard a descriptor and unmap the sgs. This will be used by the patch that will discard descriptor when packet is truncated. Cc: Michael S. Tsirkin Signed-off-by: Jason Wang Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin (cherry picked from commit 29b9f5efd78ae0f9cc02dd169b6e80d2c404bade) Signed-off-by: Ladi Prosek Signed-off-by: Miroslav Rezanina --- hw/virtio/virtio.c | 7 +++++++ include/hw/virtio/virtio.h | 2 ++ 2 files changed, 9 insertions(+) diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index 5ee899a..91c9642 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -251,6 +251,13 @@ static void virtqueue_unmap_sg(VirtQueue *vq, const VirtQueueElement *elem, 0, elem->out_sg[i].iov_len); } +void virtqueue_discard(VirtQueue *vq, const VirtQueueElement *elem, + unsigned int len) +{ + vq->last_avail_idx--; + virtqueue_unmap_sg(vq, elem, len); +} + void virtqueue_fill(VirtQueue *vq, const VirtQueueElement *elem, unsigned int len, unsigned int idx) { diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h index 9e22865..de32425 100644 --- a/include/hw/virtio/virtio.h +++ b/include/hw/virtio/virtio.h @@ -165,6 +165,8 @@ void virtio_del_queue(VirtIODevice *vdev, int n); void virtqueue_push(VirtQueue *vq, const VirtQueueElement *elem, unsigned int len); void virtqueue_flush(VirtQueue *vq, unsigned int count); +void virtqueue_discard(VirtQueue *vq, const VirtQueueElement *elem, + unsigned int len); void virtqueue_fill(VirtQueue *vq, const VirtQueueElement *elem, unsigned int len, unsigned int idx); -- 1.8.3.1