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authorEugenio Pérez <eperezma@redhat.com>2022-08-10 20:15:11 +0300
committerMichael S. Tsirkin <mst@redhat.com>2022-08-11 11:31:15 +0300
commitf345a0143b4dd1cfc850009c6979a3801b86a06f (patch)
tree7a3191db2733b0233903ac78eca7fd9ce44fc094 /include/uapi
parent0723f1df5c3ec8a1112d150dab98e149361ef488 (diff)
downloadlinux-f345a0143b4dd1cfc850009c6979a3801b86a06f.tar.xz
vhost-vdpa: uAPI to suspend the device
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>
Diffstat (limited to 'include/uapi')
-rw-r--r--include/uapi/linux/vhost.h9
1 files changed, 9 insertions, 0 deletions
diff --git a/include/uapi/linux/vhost.h b/include/uapi/linux/vhost.h
index cab645d4a645..f9f115a7c75b 100644
--- a/include/uapi/linux/vhost.h
+++ b/include/uapi/linux/vhost.h
@@ -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