在 2023/2/22 22:25, Eugenio Perez Martin 写道:
On Wed, Feb 22, 2023 at 5:05 AM Jason Wang <jasowang@xxxxxxxxxx> wrote:
在 2023/2/8 17:42, Eugenio Pérez 写道:
Next patches enable devices to be migrated even if vdpa netdev has not
been started with x-svq. However, not all devices are migratable, so we
need to block migration if we detect that.
Block vhost-vdpa device migration if it does not offer _F_SUSPEND and it
has not been started with x-svq.
Signed-off-by: Eugenio Pérez <eperezma@xxxxxxxxxx>
---
hw/virtio/vhost-vdpa.c | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)
diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
index 84a6b9690b..9d30cf9b3c 100644
--- a/hw/virtio/vhost-vdpa.c
+++ b/hw/virtio/vhost-vdpa.c
@@ -442,6 +442,27 @@ static int vhost_vdpa_init(struct vhost_dev *dev, void *opaque, Error **errp)
return 0;
}
+ /*
+ * If dev->shadow_vqs_enabled at initialization that means the device has
+ * been started with x-svq=on, so don't block migration
+ */
+ if (dev->migration_blocker == NULL && !v->shadow_vqs_enabled) {
+ uint64_t backend_features;
+
+ /* We don't have dev->backend_features yet */
+ ret = vhost_vdpa_call(dev, VHOST_GET_BACKEND_FEATURES,
+ &backend_features);
+ if (unlikely(ret)) {
+ error_setg_errno(errp, -ret, "Could not get backend features");
+ return ret;
+ }
+
+ if (!(backend_features & BIT_ULL(VHOST_BACKEND_F_SUSPEND))) {
+ error_setg(&dev->migration_blocker,
+ "vhost-vdpa backend lacks VHOST_BACKEND_F_SUSPEND feature.");
+ }
I wonder why not let the device to decide? For networking device, we can
live without suspend probably.
Right, but how can we know if this is a net device in init? I don't
think a switch (vhost_vdpa_get_device_id(dev)) is elegant.
I meant the caller of vhost_vdpa_init() which is net_init_vhost_vdpa().
Thanks
If the parent device does not need to be suspended i'd go with
exposing a suspend ioctl but do nothing in the parent device. After
that, it could even choose to return an error for GET_VRING_BASE.
If we want to implement it as a fallback in qemu, I'd go for
implementing it on top of this series. There are a few operations we
could move to a device-kind specific ops.
Would it make sense to you?
Thanks!
Thanks
+ }
+
/*
* Similar to VFIO, we end up pinning all guest memory and have to
* disable discarding of RAM.
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