hw/virtio: derive vhost-user-gpio from vhost-user-base

Now the new base class supports config handling we can take advantage
and make vhost-user-gpio a much simpler boilerplate wrapper. Also as
this

hw/virtio: derive vhost-user-gpio from vhost-user-base

Now the new base class supports config handling we can take advantage
and make vhost-user-gpio a much simpler boilerplate wrapper. Also as
this doesn't require any target specific hacks we only need to build
the stubs once.

Acked-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20240104210945.1223134-5-alex.bennee@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

show more ...

vhost-user: fix the reconnect error

If the error occurs in vhost_dev_init, the value of s->connected is set to true
in advance, and there is no chance to enter this function execution again
in the f

vhost-user: fix the reconnect error

If the error occurs in vhost_dev_init, the value of s->connected is set to true
in advance, and there is no chance to enter this function execution again
in the future.

Signed-off-by: Li Feng <fengli@smartx.com>
Message-Id: <20231123055431.217792-2-fengli@smartx.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

show more ...

vhost-user: fix lost reconnect

When the vhost-user is reconnecting to the backend, and if the vhost-user fails
at the get_features in vhost_dev_init(), then the reconnect will fail
and it will not b

vhost-user: fix lost reconnect

When the vhost-user is reconnecting to the backend, and if the vhost-user fails
at the get_features in vhost_dev_init(), then the reconnect will fail
and it will not be retriggered forever.

The reason is:
When the vhost-user fails at get_features, the vhost_dev_cleanup will be called
immediately.

vhost_dev_cleanup calls 'memset(hdev, 0, sizeof(struct vhost_dev))'.

The reconnect path is:
vhost_user_blk_event
vhost_user_async_close(.. vhost_user_blk_disconnect ..)
qemu_chr_fe_set_handlers <----- clear the notifier callback
schedule vhost_user_async_close_bh

The vhost->vdev is null, so the vhost_user_blk_disconnect will not be
called, then the event fd callback will not be reinstalled.

All vhost-user devices have this issue, including vhost-user-blk/scsi.

With this patch, if the vdev->vdev is null, the fd callback will still
be reinstalled.

Fixes: 71e076a07d ("hw/virtio: generalise CHR_EVENT_CLOSED handling")

Signed-off-by: Li Feng <fengli@smartx.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Message-Id: <20231009044735.941655-6-fengli@smartx.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

show more ...

vhost: move and rename the conn retry times

Multiple devices need this macro, move it to a common header.

Signed-off-by: Li Feng <fengli@smartx.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nu

vhost: move and rename the conn retry times

Multiple devices need this macro, move it to a common header.

Signed-off-by: Li Feng <fengli@smartx.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Message-Id: <20231009044735.941655-3-fengli@smartx.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

show more ...

vhost-user: fix lost reconnect

When the vhost-user is reconnecting to the backend, and if the vhost-user fails
at the get_features in vhost_dev_init(), then the reconnect will fail
and it will not b

vhost-user: fix lost reconnect

When the vhost-user is reconnecting to the backend, and if the vhost-user fails
at the get_features in vhost_dev_init(), then the reconnect will fail
and it will not be retriggered forever.

The reason is:
When the vhost-user fails at get_features, the vhost_dev_cleanup will be called
immediately.

vhost_dev_cleanup calls 'memset(hdev, 0, sizeof(struct vhost_dev))'.

The reconnect path is:
vhost_user_blk_event
vhost_user_async_close(.. vhost_user_blk_disconnect ..)
qemu_chr_fe_set_handlers <----- clear the notifier callback
schedule vhost_user_async_close_bh

The vhost->vdev is null, so the vhost_user_blk_disconnect will not be
called, then the event fd callback will not be reinstalled.

All vhost-user devices have this issue, including vhost-user-blk/scsi.

With this patch, if the vdev->vdev is null, the fd callback will still
be reinstalled.

Fixes: 71e076a07d ("hw/virtio: generalise CHR_EVENT_CLOSED handling")

Signed-off-by: Li Feng <fengli@smartx.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Message-Id: <20231009044735.941655-6-fengli@smartx.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

show more ...

vhost: move and rename the conn retry times

Multiple devices need this macro, move it to a common header.

Signed-off-by: Li Feng <fengli@smartx.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nu

vhost: move and rename the conn retry times

Multiple devices need this macro, move it to a common header.

Signed-off-by: Li Feng <fengli@smartx.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Message-Id: <20231009044735.941655-3-fengli@smartx.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

show more ...

vhost-user: fix lost reconnect

When the vhost-user is reconnecting to the backend, and if the vhost-user fails
at the get_features in vhost_dev_init(), then the reconnect will fail
and it will not b

vhost-user: fix lost reconnect

When the vhost-user is reconnecting to the backend, and if the vhost-user fails
at the get_features in vhost_dev_init(), then the reconnect will fail
and it will not be retriggered forever.

The reason is:
When the vhost-user fails at get_features, the vhost_dev_cleanup will be called
immediately.

vhost_dev_cleanup calls 'memset(hdev, 0, sizeof(struct vhost_dev))'.

The reconnect path is:
vhost_user_blk_event
vhost_user_async_close(.. vhost_user_blk_disconnect ..)
qemu_chr_fe_set_handlers <----- clear the notifier callback
schedule vhost_user_async_close_bh

The vhost->vdev is null, so the vhost_user_blk_disconnect will not be
called, then the event fd callback will not be reinstalled.

All vhost-user devices have this issue, including vhost-user-blk/scsi.

With this patch, if the vdev->vdev is null, the fd callback will still
be reinstalled.

Fixes: 71e076a07d ("hw/virtio: generalise CHR_EVENT_CLOSED handling")

Signed-off-by: Li Feng <fengli@smartx.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Message-Id: <20231009044735.941655-6-fengli@smartx.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

show more ...

vhost: move and rename the conn retry times

Multiple devices need this macro, move it to a common header.

Signed-off-by: Li Feng <fengli@smartx.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nu

vhost: move and rename the conn retry times

Multiple devices need this macro, move it to a common header.

Signed-off-by: Li Feng <fengli@smartx.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Message-Id: <20231009044735.941655-3-fengli@smartx.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

show more ...

qmp: update virtio feature maps, vhost-user-gpio introspection

Add new vhost-user protocol feature to vhost-user protocol feature map
and enumeration:
- VHOST_USER_PROTOCOL_F_STATUS

Add new virtio

qmp: update virtio feature maps, vhost-user-gpio introspection

Add new vhost-user protocol feature to vhost-user protocol feature map
and enumeration:
- VHOST_USER_PROTOCOL_F_STATUS

Add new virtio device features for several virtio devices to their
respective feature mappings:

virtio-blk:
- VIRTIO_BLK_F_SECURE_ERASE

virtio-net:
- VIRTIO_NET_F_NOTF_COAL
- VIRTIO_NET_F_GUEST_USO4
- VIRTIO_NET_F_GUEST_USO6
- VIRTIO_NET_F_HOST_USO

virtio/vhost-user-gpio:
- VIRTIO_GPIO_F_IRQ
- VHOST_USER_F_PROTOCOL_FEATURES

Add support for introspection on vhost-user-gpio devices.

Signed-off-by: Jonah Palmer <jonah.palmer@oracle.com>
Reviewed-by: Emmanouil Pitsidianakis <manos.pitsidianakis@linaro.org>
Message-Id: <20230926224107.2951144-3-jonah.palmer@oracle.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

show more ...

qmp: update virtio feature maps, vhost-user-gpio introspection

Add new vhost-user protocol feature to vhost-user protocol feature map
and enumeration:
- VHOST_USER_PROTOCOL_F_STATUS

Add new virtio

qmp: update virtio feature maps, vhost-user-gpio introspection

Add new vhost-user protocol feature to vhost-user protocol feature map
and enumeration:
- VHOST_USER_PROTOCOL_F_STATUS

Add new virtio device features for several virtio devices to their
respective feature mappings:

virtio-blk:
- VIRTIO_BLK_F_SECURE_ERASE

virtio-net:
- VIRTIO_NET_F_NOTF_COAL
- VIRTIO_NET_F_GUEST_USO4
- VIRTIO_NET_F_GUEST_USO6
- VIRTIO_NET_F_HOST_USO

virtio/vhost-user-gpio:
- VIRTIO_GPIO_F_IRQ
- VHOST_USER_F_PROTOCOL_FEATURES

Add support for introspection on vhost-user-gpio devices.

Signed-off-by: Jonah Palmer <jonah.palmer@oracle.com>
Reviewed-by: Emmanouil Pitsidianakis <manos.pitsidianakis@linaro.org>
Message-Id: <20230926224107.2951144-3-jonah.palmer@oracle.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

show more ...

qmp: update virtio feature maps, vhost-user-gpio introspection

Add new vhost-user protocol feature to vhost-user protocol feature map
and enumeration:
- VHOST_USER_PROTOCOL_F_STATUS

Add new virtio

qmp: update virtio feature maps, vhost-user-gpio introspection

Add new vhost-user protocol feature to vhost-user protocol feature map
and enumeration:
- VHOST_USER_PROTOCOL_F_STATUS

Add new virtio device features for several virtio devices to their
respective feature mappings:

virtio-blk:
- VIRTIO_BLK_F_SECURE_ERASE

virtio-net:
- VIRTIO_NET_F_NOTF_COAL
- VIRTIO_NET_F_GUEST_USO4
- VIRTIO_NET_F_GUEST_USO6
- VIRTIO_NET_F_HOST_USO

virtio/vhost-user-gpio:
- VIRTIO_GPIO_F_IRQ
- VHOST_USER_F_PROTOCOL_FEATURES

Add support for introspection on vhost-user-gpio devices.

Signed-off-by: Jonah Palmer <jonah.palmer@oracle.com>
Reviewed-by: Emmanouil Pitsidianakis <manos.pitsidianakis@linaro.org>
Message-Id: <20230926224107.2951144-3-jonah.palmer@oracle.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

show more ...

hw/virtio: fix typo in VIRTIO_CONFIG_IRQ_IDX comments

Fixes: 544f0278af (virtio: introduce macro VIRTIO_CONFIG_IRQ_IDX)
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <2023071015352

hw/virtio: fix typo in VIRTIO_CONFIG_IRQ_IDX comments

Fixes: 544f0278af (virtio: introduce macro VIRTIO_CONFIG_IRQ_IDX)
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20230710153522.3469097-4-alex.bennee@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

show more ...

vhost-user-gpio: Configure vhost_dev when connecting

vhost_dev_cleanup(), called from vu_gpio_disconnect(), clears vhost_dev
so vhost-user-gpio must set the members of vhost_dev each time
connecting

vhost-user-gpio: Configure vhost_dev when connecting

vhost_dev_cleanup(), called from vu_gpio_disconnect(), clears vhost_dev
so vhost-user-gpio must set the members of vhost_dev each time
connecting.

do_vhost_user_cleanup() should also acquire the pointer to vqs directly
from VHostUserGPIO instead of referring to vhost_dev as it can be called
after vhost_dev_cleanup().

Fixes: 27ba7b027f ("hw/virtio: add boilerplate for vhost-user-gpio device")
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Message-Id: <20230130140320.77999-1-akihiko.odaki@daynix.com>
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

show more ...

vhost-user-gpio: Configure vhost_dev when connecting

vhost_dev_cleanup(), called from vu_gpio_disconnect(), clears vhost_dev
so vhost-user-gpio must set the members of vhost_dev each time
connecting

vhost-user-gpio: Configure vhost_dev when connecting

vhost_dev_cleanup(), called from vu_gpio_disconnect(), clears vhost_dev
so vhost-user-gpio must set the members of vhost_dev each time
connecting.

do_vhost_user_cleanup() should also acquire the pointer to vqs directly
from VHostUserGPIO instead of referring to vhost_dev as it can be called
after vhost_dev_cleanup().

Fixes: 27ba7b027f ("hw/virtio: add boilerplate for vhost-user-gpio device")
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Message-Id: <20230130140320.77999-1-akihiko.odaki@daynix.com>
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

show more ...

virtio: introduce macro VIRTIO_CONFIG_IRQ_IDX

To support configure interrupt for vhost-vdpa
Introduce VIRTIO_CONFIG_IRQ_IDX -1 as configure interrupt's queue index,
Then we can reuse the functions g

virtio: introduce macro VIRTIO_CONFIG_IRQ_IDX

To support configure interrupt for vhost-vdpa
Introduce VIRTIO_CONFIG_IRQ_IDX -1 as configure interrupt's queue index,
Then we can reuse the functions guest_notifier_mask and guest_notifier_pending.
Add the check of queue index in these drivers, if the driver does not support
configure interrupt, the function will just return

Signed-off-by: Cindy Lu <lulu@redhat.com>
Message-Id: <20221222070451.936503-2-lulu@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

show more ...

virtio: introduce macro VIRTIO_CONFIG_IRQ_IDX

To support configure interrupt for vhost-vdpa
Introduce VIRTIO_CONFIG_IRQ_IDX -1 as configure interrupt's queue index,
Then we can reuse the functions g

virtio: introduce macro VIRTIO_CONFIG_IRQ_IDX

To support configure interrupt for vhost-vdpa
Introduce VIRTIO_CONFIG_IRQ_IDX -1 as configure interrupt's queue index,
Then we can reuse the functions guest_notifier_mask and guest_notifier_pending.
Add the check of queue index in these drivers, if the driver does not support
configure interrupt, the function will just return

Signed-off-by: Cindy Lu <lulu@redhat.com>
Message-Id: <20221222070451.936503-2-lulu@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

show more ...

virtio: introduce macro VIRTIO_CONFIG_IRQ_IDX

To support configure interrupt for vhost-vdpa
Introduce VIRTIO_CONFIG_IRQ_IDX -1 as configure interrupt's queue index,
Then we can reuse the functions g

virtio: introduce macro VIRTIO_CONFIG_IRQ_IDX

To support configure interrupt for vhost-vdpa
Introduce VIRTIO_CONFIG_IRQ_IDX -1 as configure interrupt's queue index,
Then we can reuse the functions guest_notifier_mask and guest_notifier_pending.
Add the check of queue index in these drivers, if the driver does not support
configure interrupt, the function will just return

Signed-off-by: Cindy Lu <lulu@redhat.com>
Message-Id: <20221222070451.936503-2-lulu@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

show more ...

hw/virtio: generalise CHR_EVENT_CLOSED handling

..and use for both virtio-user-blk and virtio-user-gpio. This avoids
the circular close by deferring shutdown due to disconnection until a
later point

hw/virtio: generalise CHR_EVENT_CLOSED handling

..and use for both virtio-user-blk and virtio-user-gpio. This avoids
the circular close by deferring shutdown due to disconnection until a
later point. virtio-user-blk already had this mechanism in place so
generalise it as a vhost-user helper function and use for both blk and
gpio devices.

While we are at it we also fix up vhost-user-gpio to re-establish the
event handler after close down so we can reconnect later.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Message-Id: <20221130112439.2527228-5-alex.bennee@linaro.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

show more ...

hw/virtio: add started_vu status field to vhost-user-gpio

As per the fix to vhost-user-blk in f5b22d06fb (vhost: recheck dev
state in the vhost_migration_log routine) we really should track the
conn

hw/virtio: add started_vu status field to vhost-user-gpio

As per the fix to vhost-user-blk in f5b22d06fb (vhost: recheck dev
state in the vhost_migration_log routine) we really should track the
connection and starting separately.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20221130112439.2527228-4-alex.bennee@linaro.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

show more ...

vhost: enable vrings in vhost_dev_start() for vhost-user devices

Commit 02b61f38d3 ("hw/virtio: incorporate backend features in features")
properly negotiates VHOST_USER_F_PROTOCOL_FEATURES with the

vhost: enable vrings in vhost_dev_start() for vhost-user devices

Commit 02b61f38d3 ("hw/virtio: incorporate backend features in features")
properly negotiates VHOST_USER_F_PROTOCOL_FEATURES with the vhost-user
backend, but we forgot to enable vrings as specified in
docs/interop/vhost-user.rst:

If ``VHOST_USER_F_PROTOCOL_FEATURES`` has not been negotiated, the
ring starts directly in the enabled state.

If ``VHOST_USER_F_PROTOCOL_FEATURES`` has been negotiated, the ring is
initialized in a disabled state and is enabled by
``VHOST_USER_SET_VRING_ENABLE`` with parameter 1.

Some vhost-user front-ends already did this by calling
vhost_ops.vhost_set_vring_enable() directly:
- backends/cryptodev-vhost.c
- hw/net/virtio-net.c
- hw/virtio/vhost-user-gpio.c

But most didn't do that, so we would leave the vrings disabled and some
backends would not work. We observed this issue with the rust version of
virtiofsd [1], which uses the event loop [2] provided by the
vhost-user-backend crate where requests are not processed if vring is
not enabled.

Let's fix this issue by enabling the vrings in vhost_dev_start() for
vhost-user front-ends that don't already do this directly. Same thing
also in vhost_dev_stop() where we disable vrings.

[1] https://gitlab.com/virtio-fs/virtiofsd
[2] https://github.com/rust-vmm/vhost/blob/240fc2966/crates/vhost-user-backend/src/event_loop.rs#L217

Fixes: 02b61f38d3 ("hw/virtio: incorporate backend features in features")
Reported-by: German Maglione <gmaglione@redhat.com>
Tested-by: German Maglione <gmaglione@redhat.com>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Acked-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Message-Id: <20221123131630.52020-1-sgarzare@redhat.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20221130112439.2527228-3-alex.bennee@linaro.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

show more ...

hw/virtio: generalise CHR_EVENT_CLOSED handling

..and use for both virtio-user-blk and virtio-user-gpio. This avoids
the circular close by deferring shutdown due to disconnection until a
later point

hw/virtio: generalise CHR_EVENT_CLOSED handling

..and use for both virtio-user-blk and virtio-user-gpio. This avoids
the circular close by deferring shutdown due to disconnection until a
later point. virtio-user-blk already had this mechanism in place so
generalise it as a vhost-user helper function and use for both blk and
gpio devices.

While we are at it we also fix up vhost-user-gpio to re-establish the
event handler after close down so we can reconnect later.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Message-Id: <20221130112439.2527228-5-alex.bennee@linaro.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

show more ...

hw/virtio: add started_vu status field to vhost-user-gpio

As per the fix to vhost-user-blk in f5b22d06fb (vhost: recheck dev
state in the vhost_migration_log routine) we really should track the
conn

hw/virtio: add started_vu status field to vhost-user-gpio

As per the fix to vhost-user-blk in f5b22d06fb (vhost: recheck dev
state in the vhost_migration_log routine) we really should track the
connection and starting separately.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20221130112439.2527228-4-alex.bennee@linaro.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

show more ...

vhost: enable vrings in vhost_dev_start() for vhost-user devices

Commit 02b61f38d3 ("hw/virtio: incorporate backend features in features")
properly negotiates VHOST_USER_F_PROTOCOL_FEATURES with the

vhost: enable vrings in vhost_dev_start() for vhost-user devices

Commit 02b61f38d3 ("hw/virtio: incorporate backend features in features")
properly negotiates VHOST_USER_F_PROTOCOL_FEATURES with the vhost-user
backend, but we forgot to enable vrings as specified in
docs/interop/vhost-user.rst:

If ``VHOST_USER_F_PROTOCOL_FEATURES`` has not been negotiated, the
ring starts directly in the enabled state.

If ``VHOST_USER_F_PROTOCOL_FEATURES`` has been negotiated, the ring is
initialized in a disabled state and is enabled by
``VHOST_USER_SET_VRING_ENABLE`` with parameter 1.

Some vhost-user front-ends already did this by calling
vhost_ops.vhost_set_vring_enable() directly:
- backends/cryptodev-vhost.c
- hw/net/virtio-net.c
- hw/virtio/vhost-user-gpio.c

But most didn't do that, so we would leave the vrings disabled and some
backends would not work. We observed this issue with the rust version of
virtiofsd [1], which uses the event loop [2] provided by the
vhost-user-backend crate where requests are not processed if vring is
not enabled.

Let's fix this issue by enabling the vrings in vhost_dev_start() for
vhost-user front-ends that don't already do this directly. Same thing
also in vhost_dev_stop() where we disable vrings.

[1] https://gitlab.com/virtio-fs/virtiofsd
[2] https://github.com/rust-vmm/vhost/blob/240fc2966/crates/vhost-user-backend/src/event_loop.rs#L217

Fixes: 02b61f38d3 ("hw/virtio: incorporate backend features in features")
Reported-by: German Maglione <gmaglione@redhat.com>
Tested-by: German Maglione <gmaglione@redhat.com>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Acked-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Message-Id: <20221123131630.52020-1-sgarzare@redhat.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20221130112439.2527228-3-alex.bennee@linaro.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

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vhost: mask VIRTIO_F_RING_RESET for vhost and vhost-user devices

Commit 69e1c14aa2 ("virtio: core: vq reset feature negotation support")
enabled VIRTIO_F_RING_RESET by default for all virtio devices

vhost: mask VIRTIO_F_RING_RESET for vhost and vhost-user devices

Commit 69e1c14aa2 ("virtio: core: vq reset feature negotation support")
enabled VIRTIO_F_RING_RESET by default for all virtio devices.

This feature is not currently emulated by QEMU, so for vhost and
vhost-user devices we need to make sure it is supported by the offloaded
device emulation (in-kernel or in another process).
To do this we need to add VIRTIO_F_RING_RESET to the features bitmap
passed to vhost_get_features(). This way it will be masked if the device
does not support it.

This issue was initially discovered with vhost-vsock and vhost-user-vsock,
and then also tested with vhost-user-rng which confirmed the same issue.
They fail when sending features through VHOST_SET_FEATURES ioctl or
VHOST_USER_SET_FEATURES message, since VIRTIO_F_RING_RESET is negotiated
by the guest (Linux >= v6.0), but not supported by the device.

Fixes: 69e1c14aa2 ("virtio: core: vq reset feature negotation support")
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1318
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Message-Id: <20221121101101.29400-1-sgarzare@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Acked-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Acked-by: Jason Wang <jasowang@redhat.com>

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hw/virtio: introduce virtio_device_should_start

The previous fix to virtio_device_started revealed a problem in its
use by both the core and the device code. The core code should be able
to handle t

hw/virtio: introduce virtio_device_should_start

The previous fix to virtio_device_started revealed a problem in its
use by both the core and the device code. The core code should be able
to handle the device "starting" while the VM isn't running to handle
the restoration of migration state. To solve this duel use introduce a
new helper for use by the vhost-user backends who all use it to feed a
should_start variable.

We can also pick up a change vhost_user_blk_set_status while we are at
it which follows the same pattern.

Fixes: 9f6bcfd99f (hw/virtio: move vm_running check to virtio_device_started)
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Message-Id: <20221107121407.1010913-1-alex.bennee@linaro.org>

show more ...