From 2f134d800a7ac521a637a0da2116b2603b12c8c0 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Eugenio=20P=C3=A9rez?= Date: Tue, 23 Aug 2022 20:30:29 +0200 Subject: [PATCH 14/23] vhost: Do not depend on !NULL VirtQueueElement on vhost_svq_flush MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit RH-Author: Eugenio Pérez RH-MergeRequest: 116: vdpa: Restore device state on destination RH-Bugzilla: 2114060 RH-Acked-by: Cindy Lu RH-Acked-by: Miroslav Rezanina RH-Commit: [13/21] 93ec7baa2a29031db25d86b7dc1a949388623370 (eperezmartin/qemu-kvm) Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2114060 Upstream status: git@github.com:jasowang/qemu.git net-next Since QEMU will be able to inject new elements on CVQ to restore the state, we need not to depend on a VirtQueueElement to know if a new element has been used by the device or not. Instead of check that, check if there are new elements only using used idx on vhost_svq_flush. Signed-off-by: Eugenio Pérez Acked-by: Jason Wang Signed-off-by: Jason Wang (cherry picked from commit 7599f71c11c08b90f173c35ded1aaa1fdca86f1b) --- hw/virtio/vhost-shadow-virtqueue.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c index d36afbc547..c0e3c92e96 100644 --- a/hw/virtio/vhost-shadow-virtqueue.c +++ b/hw/virtio/vhost-shadow-virtqueue.c @@ -499,17 +499,20 @@ static void vhost_svq_flush(VhostShadowVirtqueue *svq, size_t vhost_svq_poll(VhostShadowVirtqueue *svq) { int64_t start_us = g_get_monotonic_time(); + uint32_t len; + do { - uint32_t len; - VirtQueueElement *elem = vhost_svq_get_buf(svq, &len); - if (elem) { - return len; + if (vhost_svq_more_used(svq)) { + break; } if (unlikely(g_get_monotonic_time() - start_us > 10e6)) { return 0; } } while (true); + + vhost_svq_get_buf(svq, &len); + return len; } /** -- 2.31.1