bianbu-repo-mirror/bianbu-linux-6.6
1
0
Fork 0
mirror of https://gitee.com/bianbu-linux/linux-6.6 synced 2025-06-29 23:43:21 -04:00
Code Issues Projects Releases Packages Wiki Activity Actions

vhost-vdpa: uAPI to suspend the device

Browse source 
The ioctl adds support for suspending the device from userspace.

This is a must before getting virtqueue indexes (base) for live migration,
since the device could modify them after userland gets them. There are
individual ways to perform that action for some devices
(VHOST_NET_SET_BACKEND, VHOST_VSOCK_SET_RUNNING, ...) but there was no
way to perform it for any vhost device (and, in particular, vhost-vdpa).

After a successful return of the ioctl call the device must not process
more virtqueue descriptors. The device can answer to read or writes of
config fields as if it were not suspended. In particular, writing to
"queue_enable" with a value of 1 will not make the device start
processing buffers of the virtqueue.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Message-Id: <20220810171512.2343333-4-eperezma@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Eugenio Pérez 2022-08-10 19:15:11 +02:00 • committed by Michael S. Tsirkin
parent 0723f1df5c
commit f345a0143b
2 changed files with 28 additions and 0 deletions
Download patch file Download diff file Expand all files Collapse all files

9
include/uapi/linux/vhost.h
View file

@ -171,4 +171,13 @@
#define VHOST_VDPA_SET_GROUP_ASID _IOW(VHOST_VIRTIO, 0x7C, \
struct vhost_vring_state)
/* Suspend a device so it does not process virtqueue requests anymore
*
* After the return of ioctl the device must preserve all the necessary state
* (the virtqueue vring base plus the possible device specific states) that is
* required for restoring in the future. The device must not change its
* configuration after that point.
*/
#define VHOST_VDPA_SUSPEND _IO(VHOST_VIRTIO, 0x7D)
#endif