absent) there is no way to disable this feature on the backend
during
runtime.
This commit slightly changes the semantics of the protocol feature
VHOST_USER_PROTOCOL_F_GET_VRING_BASE_INFLIGHT. Enabling this
feature
adds a new parameter for GET_VRING_BASE, which allows to control
the
drain in-flight requests on the backend.
Thus, QEMU will be able to turn this feature on GET_VRING_BASE
off and
on anytime.
In vhost-user-blk use inflight_migration param to enable
skip_drain to
suspend in-flight I/O requests, and then migrate them throught
inflight
subsection.
Also now QEMU will always try to setup
VHOST_USER_PROTOCOL_F_GET_VRING_BASE_INFLIGHT protocol featrue with
backend. This will allow to use skip_drain parameter on
GET_VRING_BASE
message.
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-
team.ru>
Signed-off-by: Alexandr Moshkov <[email protected]>
---
docs/interop/vhost-user.rst | 6 ++----
hw/block/vhost-user-blk.c | 30 +++++++++++++++++++++++
+------
hw/virtio/vhost-user.c | 3 +--
hw/virtio/vhost.c | 1 +
include/hw/virtio/vhost-user.h | 1 -
5 files changed, 28 insertions(+), 13 deletions(-)
diff --git a/docs/interop/vhost-user.rst b/docs/interop/vhost-
user.rst
index bfa75ff9a3..63efc87264 100644
--- a/docs/interop/vhost-user.rst
+++ b/docs/interop/vhost-user.rst
@@ -1255,14 +1255,12 @@ Front-end message types
*suspended*, see :ref:`Suspended device state
<suspended_device_state>`.
- The request payload's *num* field is currently reserved and
must be
- set to 0.
-
By default, the back-end must complete all inflight I/O
requests for the
specified vring before stopping it.
If the ``VHOST_USER_PROTOCOL_F_GET_VRING_BASE_INFLIGHT``
protocol
- feature has been negotiated, the back-end may suspend in-
flight I/O
+ feature has been negotiated, using request payload's *num*
field,
+ when *num* is set to 1, QEMU can tell the back-end to suspend
in- flight I/O
requests and record them as described in :ref:`Inflight I/O
tracking
<inflight_io_tracking>` instead of completing them before
stopping the vring.
How to suspend an in-flight request depends on the
implementation of the back-end
diff --git a/hw/block/vhost-user-blk.c b/hw/block/vhost-user-blk.c
index a3ecd83f54..522e9d34b5 100644
--- a/hw/block/vhost-user-blk.c
+++ b/hw/block/vhost-user-blk.c
@@ -134,10 +134,7 @@ static bool
vhost_user_blk_inflight_needed(void *opaque)
{
struct VHostUserBlk *s = opaque;
- bool inflight_migration = virtio_has_feature(s-
>dev.protocol_features,
- VHOST_USER_PROTOCOL_F_GET_VRING_BASE_INFLIGHT);
-
- return inflight_migration;
+ return s->inflight_migration;
}
@@ -232,11 +229,14 @@ static int
vhost_user_blk_stop(VirtIODevice *vdev)
return 0;
}
+ bool skip_drain = vhost_user_blk_inflight_needed(s) &&
+ runstate_check(RUN_STATE_FINISH_MIGRATE);
+
force_stop = s->skip_get_vring_base_on_force_shutdown &&
qemu_force_shutdown_requested();
ret = force_stop ? vhost_dev_force_stop(&s->dev, vdev,
true) :
- vhost_dev_stop(&s->dev, vdev, true, false);
+ vhost_dev_stop(&s->dev, vdev, true,
skip_drain);
if (k->set_guest_notifiers(qbus->parent, s->dev.nvqs,
false) < 0) {
error_report("vhost guest notifier cleanup failed:
%d", ret);
@@ -364,7 +364,6 @@ static int
vhost_user_blk_connect(DeviceState *dev, Error **errp)
vhost_dev_set_config_notifier(&s->dev, &blk_ops);
s->vhost_user.supports_config = true;
- s->vhost_user.supports_inflight_migration = s-
>inflight_migration;
ret = vhost_dev_init(&s->dev, &s->vhost_user,
VHOST_BACKEND_TYPE_USER, 0,
errp);
if (ret < 0) {
@@ -580,10 +579,29 @@ static struct vhost_dev
*vhost_user_blk_get_vhost(VirtIODevice *vdev)
return &s->dev;
}
+static bool vhost_user_blk_pre_save(void *opaque, Error **errp)
+{
+ VHostUserBlk *s = VHOST_USER_BLK(opaque);
+
+ bool inflight_migration_enabled = virtio_has_feature(
+ s->dev.protocol_features,
+ VHOST_USER_PROTOCOL_F_GET_VRING_BASE_INFLIGHT);
+ if (vhost_user_blk_inflight_needed(s) && !
inflight_migration_enabled) {
+ error_setg(errp, "can't migrate vhost-user-blk device: "
+ "backend doesn't support "
+ "VHOST_USER_PROTOCOL_F_GET_VRING_BASE_INFLIGHT "
+ "protocol feature");
+ return false;
+ }
+
+ return true;
+}
+
static const VMStateDescription
vmstate_vhost_user_blk_inflight = {
.name = "vhost-user-blk/inflight",
.version_id = 1,
.needed = vhost_user_blk_inflight_needed,
+ .pre_save_errp = vhost_user_blk_pre_save,
.fields = (const VMStateField[]) {
VMSTATE_VHOST_INFLIGHT_REGION(inflight, VHostUserBlk),
VMSTATE_END_OF_LIST()
diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
index bb8f8eab77..ed95ec7523 100644
--- a/hw/virtio/vhost-user.c
+++ b/hw/virtio/vhost-user.c
@@ -2225,8 +2225,7 @@ static int vhost_user_backend_init(struct
vhost_dev *dev, void *opaque,
}
}
- if (!u->user->supports_inflight_migration ||
- !virtio_has_feature(protocol_features,
+ if (!virtio_has_feature(protocol_features,
VHOST_USER_PROTOCOL_F_INFLIGHT_SHMFD)) {
protocol_features &= ~(1ULL <<
VHOST_USER_PROTOCOL_F_GET_VRING_BASE_INFLIGHT);
diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index ac4d6fca73..54e4ce2660 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -1398,6 +1398,7 @@ static int do_vhost_virtqueue_stop(struct
vhost_dev *dev,
int vhost_vq_index = dev->vhost_ops-
>vhost_get_vq_index(dev, idx);
struct vhost_vring_state state = {
.index = vhost_vq_index,
+ .num = skip_drain,
};
int r = 0;
diff --git a/include/hw/virtio/vhost-user.h b/include/hw/
virtio/ vhost-user.h
index 53fe996686..c95bad5ddc 100644
--- a/include/hw/virtio/vhost-user.h
+++ b/include/hw/virtio/vhost-user.h
@@ -69,7 +69,6 @@ typedef struct VhostUserState {
GPtrArray *notifiers;
int memory_slots;
bool supports_config;
- bool supports_inflight_migration;
} VhostUserState;
/**
