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authorKevin Wolf <kwolf@redhat.com>2024-03-15 16:59:49 +0100
committerKevin Wolf <kwolf@redhat.com>2024-03-26 14:21:26 +0100
commit2c66de61f88dc9620a32239f7dd61524a57f66b0 (patch)
tree9afc1c2f0dd6031b29b3d814cf5f6e7e81f8ced1 /hw/virtio/vhost-vdpa.c
parentd9e4070603b9727a8c33d9aa7d2aacf5eed0c0f7 (diff)
downloadfocaccia-qemu-2c66de61f88dc9620a32239f7dd61524a57f66b0.tar.gz
focaccia-qemu-2c66de61f88dc9620a32239f7dd61524a57f66b0.zip
vdpa-dev: Fix initialisation order to restore VDUSE compatibility
VDUSE requires that virtqueues are first enabled before the DRIVER_OK
status flag is set; with the current API of the kernel module, it is
impossible to enable the opposite order in our block export code because
userspace is not notified when a virtqueue is enabled.

This requirement also mathces the normal initialisation order as done by
the generic vhost code in QEMU. However, commit 6c482547 accidentally
changed the order for vdpa-dev and broke access to VDUSE devices with
this.

This changes vdpa-dev to use the normal order again and use the standard
vhost callback .vhost_set_vring_enable for this. VDUSE devices can be
used with vdpa-dev again after this fix.

vhost_net intentionally avoided enabling the vrings for vdpa and does
this manually later while it does enable them for other vhost backends.
Reflect this in the vhost_net code and return early for vdpa, so that
the behaviour doesn't change for this device.

Cc: qemu-stable@nongnu.org
Fixes: 6c4825476a43 ('vdpa: move vhost_vdpa_set_vring_ready to the caller')
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-ID: <20240315155949.86066-1-kwolf@redhat.com>
Reviewed-by: Eugenio Pérez <eperezma@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'hw/virtio/vhost-vdpa.c')
-rw-r--r--hw/virtio/vhost-vdpa.c29
1 files changed, 26 insertions, 3 deletions
diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
index 3bcd05cc22..e827b9175f 100644
--- a/hw/virtio/vhost-vdpa.c
+++ b/hw/virtio/vhost-vdpa.c
@@ -896,19 +896,41 @@ static int vhost_vdpa_get_vq_index(struct vhost_dev *dev, int idx)
     return idx;
 }
 
-int vhost_vdpa_set_vring_ready(struct vhost_vdpa *v, unsigned idx)
+static int vhost_vdpa_set_vring_enable_one(struct vhost_vdpa *v, unsigned idx,
+                                           int enable)
 {
     struct vhost_dev *dev = v->dev;
     struct vhost_vring_state state = {
         .index = idx,
-        .num = 1,
+        .num = enable,
     };
     int r = vhost_vdpa_call(dev, VHOST_VDPA_SET_VRING_ENABLE, &state);
 
-    trace_vhost_vdpa_set_vring_ready(dev, idx, r);
+    trace_vhost_vdpa_set_vring_enable_one(dev, idx, enable, r);
     return r;
 }
 
+static int vhost_vdpa_set_vring_enable(struct vhost_dev *dev, int enable)
+{
+    struct vhost_vdpa *v = dev->opaque;
+    unsigned int i;
+    int ret;
+
+    for (i = 0; i < dev->nvqs; ++i) {
+        ret = vhost_vdpa_set_vring_enable_one(v, i, enable);
+        if (ret < 0) {
+            return ret;
+        }
+    }
+
+    return 0;
+}
+
+int vhost_vdpa_set_vring_ready(struct vhost_vdpa *v, unsigned idx)
+{
+    return vhost_vdpa_set_vring_enable_one(v, idx, 1);
+}
+
 static int vhost_vdpa_set_config_call(struct vhost_dev *dev,
                                        int fd)
 {
@@ -1536,6 +1558,7 @@ const VhostOps vdpa_ops = {
         .vhost_set_features = vhost_vdpa_set_features,
         .vhost_reset_device = vhost_vdpa_reset_device,
         .vhost_get_vq_index = vhost_vdpa_get_vq_index,
+        .vhost_set_vring_enable = vhost_vdpa_set_vring_enable,
         .vhost_get_config  = vhost_vdpa_get_config,
         .vhost_set_config = vhost_vdpa_set_config,
         .vhost_requires_shm_log = NULL,