[v1] virtio,pc,pci: features, cleanups, fixes

[PULL 08/21] vdpa: do not set virtio status bits if unneeded

Michael S. Tsirkin posted 21 patches 11 months ago

Diff against v1 v1 v1 v1 v1 v1 v1 v2 v4
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Maintainers: "Michael S. Tsirkin" <mst@redhat.com>, Igor Mammedov <imammedo@redhat.com>, Ani Sinha <anisinha@redhat.com>, Gerd Hoffmann <kraxel@redhat.com>, Paolo Bonzini <pbonzini@redhat.com>, Fam Zheng <fam@euphon.net>, Raphael Norwitz <raphael.norwitz@nutanix.com>, Mathieu Poirier <mathieu.poirier@linaro.org>, Jason Wang <jasowang@redhat.com>

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[PULL 08/21] vdpa: do not set virtio status bits if unneeded

Posted by Michael S. Tsirkin 11 months ago

From: Eugenio Pérez <eperezma@redhat.com>

Next commits will set DRIVER and ACKNOWLEDGE flags repeatedly in the
case of a migration destination.  Let's save ioctls with this.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Message-Id: <20231215172830.2540987-2-eperezma@redhat.com>
---
 hw/virtio/vhost-vdpa.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
index 819b2d811a..401dfa96fd 100644
--- a/hw/virtio/vhost-vdpa.c
+++ b/hw/virtio/vhost-vdpa.c
@@ -511,6 +511,10 @@ static int vhost_vdpa_add_status(struct vhost_dev *dev, uint8_t status)
     if (ret < 0) {
         return ret;
     }
+    if ((s & status) == status) {
+        /* Don't set bits already set */
+        return 0;
+    }
 
     s |= status;
 
-- 
MST