..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>
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>
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>
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>
This patch is part of adding vhost-user vhost_dev_start support. The
motivation is to improve backend configuration speed and reduce live
migration VM downtime.
Moving the device start routines after finishing all the necessary device
and VQ configuration, further aligning to the virtio specification for
"device initialization sequence".
Following patch will add vhost-user vhost_dev_start support.
Signed-off-by: Yajun Wu <yajunw@nvidia.com>
Acked-by: Parav Pandit <parav@nvidia.com>
Message-Id: <20221017064452.1226514-2-yajunw@nvidia.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
If the os is not installed and doesn't have the virtio guest driver,
the vhost dev isn't started, so the dev->vdev is NULL.
Reproduce: mount a Win 2019 iso, go into the install ui, then resize
the virtio-blk device, qemu crash.
Signed-off-by: Li Feng <fengli@smartx.com>
Message-Id: <20220919121816.3252223-1-fengli@smartx.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Make vhost-user-blk backwards compatible when migrating from older VMs
running with modern features turned off, the same way it was done for
virtio-blk in 20764be042 ("virtio-blk: set config size depending on the features enabled")
It's currently impossible to migrate from an older VM with
vhost-user-blk (with disable-legacy=off) because of errors like this:
qemu-system-x86_64: get_pci_config_device: Bad config data: i=0x10 read: 41 device: 1 cmask: ff wmask: 80 w1cmask:0
qemu-system-x86_64: Failed to load PCIDevice:config
qemu-system-x86_64: Failed to load virtio-blk:virtio
qemu-system-x86_64: error while loading state for instance 0x0 of device '0000:00:05.0:00.0:02.0/virtio-blk'
qemu-system-x86_64: load of migration failed: Invalid argument
This is caused by the newer (destination) VM requiring a bigger BAR0
alignment because it has to cover a bigger configuration space, which
isn't actually needed since those additional config fields are not
active (write-zeroes/discard).
Signed-off-by: Daniil Tatianin <d-tatianin@yandex-team.ru>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Message-Id: <20220906073111.353245-6-d-tatianin@yandex-team.ru>
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>
No reason to have this be a separate field. This also makes it more akin
to what the virtio-blk device does.
Signed-off-by: Daniil Tatianin <d-tatianin@yandex-team.ru>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Message-Id: <20220906073111.353245-5-d-tatianin@yandex-team.ru>
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>
It is useful to have the ability to disable these features for
compatibility with older VMs that don't have these implemented.
Signed-off-by: Daniil Tatianin <d-tatianin@yandex-team.ru>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Message-Id: <20220906073111.353245-4-d-tatianin@yandex-team.ru>
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>
The `started` field is manipulated internally within the vhost code
except for one place, vhost-user-blk via f5b22d06fb (vhost: recheck
dev state in the vhost_migration_log routine). Mark that as a FIXME
because it introduces a potential race. I think the referenced fix
should be tracking its state locally.
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20220802095010.3330793-12-alex.bennee@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Raphael Norwitz <raphael.norwittz@nutanix.com>
Currently vhost-user-scsi driver doesn't allow to change
the configuration space of virtio_scsi, while vhost-user-blk
support that, so here we set the flag in vhost-user-blk driver
and unset it in vhost-user-scsi.
Signed-off-by: Changpeng Liu <changpeng.liu@intel.com>
Message-Id: <20220525125540.50979-2-changpeng.liu@intel.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Changpeng Liu <changpeng.liu@intel.com>
Signed-off-by: Changpeng Liu <changpeng.liu@intel.com>
This patch adds a get_vhost() callback function for VirtIODevices that
returns the device's corresponding vhost_dev structure, if the vhost
device is running. This patch also adds a vhost_started flag for
VirtIODevices.
Previously, a VirtIODevice wouldn't be able to tell if its corresponding
vhost device was active or not.
Signed-off-by: Jonah Palmer <jonah.palmer@oracle.com>
Message-Id: <1648819405-25696-3-git-send-email-jonah.palmer@oracle.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This patch drops the name parameter for the virtio_init function.
The pair between the numeric device ID and the string device ID
(name) of a virtio device already exists, but not in a way that
lets us map between them.
This patch lets us do this and removes the need for the name
parameter in the virtio_init function.
Signed-off-by: Jonah Palmer <jonah.palmer@oracle.com>
Message-Id: <1648819405-25696-2-git-send-email-jonah.palmer@oracle.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Turn on pre-defined feature VIRTIO_BLK_F_SIZE_MAX for virtio blk device to
avoid guest DMA request sizes which are too large for hardware spec.
Signed-off-by: Andy Pei <andy.pei@intel.com>
Message-Id: <1641202092-149677-1-git-send-email-andy.pei@intel.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Fix the only callsite that doesn't propagate the error code from the
generic vhost code.
Signed-off-by: Roman Kagan <rvkagan@yandex-team.ru>
Message-Id: <20211111153354.18807-11-rvkagan@yandex-team.ru>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
vhost-user-blk realize only attempts to reconnect if the previous
connection attempt failed on "a problem with the connection and not an
error related to the content (which would fail again the same way in the
next attempt)".
However this distinction is very subtle, and may be inadvertently broken
if the code changes somewhere deep down the stack and a new error gets
propagated up to here.
OTOH now that the number of reconnection attempts is limited it seems
harmless to try reconnecting on any error.
So relax the condition of whether to retry connecting to check for any
error.
This patch amends a527e312b5 "vhost-user-blk: Implement reconnection
during realize".
Signed-off-by: Roman Kagan <rvkagan@yandex-team.ru>
Message-Id: <20211111153354.18807-2-rvkagan@yandex-team.ru>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Commit dabefdd6 removed code that was supposed to try reconnecting
during .realize(), but actually just crashed and had several design
problems.
This adds the feature back without the crash in simple cases while also
fixing some design problems: Reconnection is now only tried if there was
a problem with the connection and not an error related to the content
(which would fail again the same way in the next attempt). Reconnection
is limited to three attempts (four with the initial attempt) so that we
won't end up in an infinite loop if a problem is permanent. If the
backend restarts three times in the very short time window of device
initialisation, we have bigger problems and erroring out is the right
course of action.
In the case that a connection error occurs and we reconnect, the error
message is printed using error_report_err(), but otherwise ignored.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20210609154658.350308-8-kwolf@redhat.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This function is the part that we will want to retry if the connection
is lost during initialisation, so factor it out to keep the following
patch simpler.
The error path for vhost_dev_get_config() forgot disconnecting the
chardev, add this while touching the code.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20210609154658.350308-7-kwolf@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Instead of just returning 0/-1 and letting the caller make up a
meaningless error message, add an Error parameter to allow reporting the
real error and switch to 0/-errno so that different kind of errors can
be distinguished in the caller.
config_len in vhost_user_get_config() is defined by the device, so if
it's larger than VHOST_USER_MAX_CONFIG_SIZE, this is a programming
error. Turn the corresponding check into an assertion.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20210609154658.350308-6-kwolf@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Instead of letting the caller make up a meaningless error message, add
an Error parameter to allow reporting the real error.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20210609154658.350308-5-kwolf@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This allows callers to return better error messages instead of making
one up while the real error ends up on stderr. Most callers can
immediately make use of this because they already have an Error
parameter themselves. The others just keep printing the error with
error_report_err().
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20210609154658.350308-2-kwolf@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Creating a device with a number of queues that isn't supported by the
backend is pointless, the device won't work properly and the error
messages are rather confusing.
Just fail to create the device if num-queues is higher than what the
backend supports.
Since the relationship between num-queues and the number of virtqueues
depends on the specific device, this is an additional value that needs
to be initialised by the device. For convenience, allow leaving it 0 if
the check should be skipped. This makes sense for vhost-user-net where
separate vhost devices are used for the queues and custom initialisation
code is needed to perform the check.
Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1935031
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Message-Id: <20210429171316.162022-7-kwolf@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
VIRTIO_F_RING_PACKED and VIRTIO_F_IOMMU_PLATFORM need to be supported by
the vhost device, otherwise advertising it to the guest doesn't result
in a working configuration. They are currently not supported by the
vhost-user-blk export in QEMU.
Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1935020
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Acked-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Message-Id: <20210429171316.162022-5-kwolf@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Now that vhost_user_blk_connect() is not called from an event handler
any more, but directly from vhost_user_blk_device_realize(), we can
actually make use of Error again instead of calling error_report() in
the inner function and setting a more generic and therefore less useful
error message in realize() itself.
With Error, the callers are responsible for adding context if necessary
(such as the "-device" option the error refers to). Additional prefixes
are redundant and better omitted.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Acked-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Message-Id: <20210429171316.162022-4-kwolf@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This is a partial revert of commits 77542d4314 and bc79c87bcd.
Usually, an error during initialisation means that the configuration was
wrong. Reconnecting won't make the error go away, but just turn the
error condition into an endless loop. Avoid this and return errors
again.
Additionally, calling vhost_user_blk_disconnect() from the chardev event
handler could result in use-after-free because none of the
initialisation code expects that the device could just go away in the
middle. So removing the call fixes crashes in several places.
For example, using a num-queues setting that is incompatible with the
backend would result in a crash like this (dereferencing dev->opaque,
which is already NULL):
#0 0x0000555555d0a4bd in vhost_user_read_cb (source=0x5555568f4690, condition=(G_IO_IN | G_IO_HUP), opaque=0x7fffffffcbf0) at ../hw/virtio/vhost-user.c:313
#1 0x0000555555d950d3 in qio_channel_fd_source_dispatch (source=0x555557c3f750, callback=0x555555d0a478 <vhost_user_read_cb>, user_data=0x7fffffffcbf0) at ../io/channel-watch.c:84
#2 0x00007ffff7b32a9f in g_main_context_dispatch () at /lib64/libglib-2.0.so.0
#3 0x00007ffff7b84a98 in g_main_context_iterate.constprop () at /lib64/libglib-2.0.so.0
#4 0x00007ffff7b32163 in g_main_loop_run () at /lib64/libglib-2.0.so.0
#5 0x0000555555d0a724 in vhost_user_read (dev=0x555557bc62f8, msg=0x7fffffffcc50) at ../hw/virtio/vhost-user.c:402
#6 0x0000555555d0ee6b in vhost_user_get_config (dev=0x555557bc62f8, config=0x555557bc62ac "", config_len=60) at ../hw/virtio/vhost-user.c:2133
#7 0x0000555555d56d46 in vhost_dev_get_config (hdev=0x555557bc62f8, config=0x555557bc62ac "", config_len=60) at ../hw/virtio/vhost.c:1566
#8 0x0000555555cdd150 in vhost_user_blk_device_realize (dev=0x555557bc60b0, errp=0x7fffffffcf90) at ../hw/block/vhost-user-blk.c:510
#9 0x0000555555d08f6d in virtio_device_realize (dev=0x555557bc60b0, errp=0x7fffffffcff0) at ../hw/virtio/virtio.c:3660
Note that this removes the ability to reconnect during initialisation
(but not during operation) when there is no permanent error, but the
backend restarts, as the implementation was buggy. This feature can be
added back in a follow-up series after changing error paths to
distinguish cases where retrying could help from cases with permanent
errors.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20210429171316.162022-3-kwolf@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
We have to set errp before jumping to virtio_err, otherwise the caller
(virtio_device_realize()) will take this as success and crash when it
later tries to access things that we've already freed in the error path.
Fixes: 77542d4314
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20210429171316.162022-2-kwolf@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Acked-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
virtio_add_queue() aborts when queue_size > VIRTQUEUE_MAX_SIZE, so
vhost_user_blk_device_realize() should check this before calling it.
Simple reproducer:
qemu-system-x86_64 \
-chardev null,id=foo \
-device vhost-user-blk-pci,queue-size=4096,chardev=foo
Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1935014
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20210413165654.50810-1-kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Qemu crashes on shutdown if the chardev used by vhost-user-blk has been
finalized before the vhost-user-blk.
This happens with char-socket chardev operating in the listening mode (server).
The char-socket chardev emits "close" event at the end of finalizing when
its internal data is destroyed. This calls vhost-user-blk event handler
which in turn tries to manipulate with destroyed chardev by setting an empty
event handler for vhost-user-blk cleanup postponing.
This patch separates the shutdown case from the cleanup postponing removing
the need to set an event handler.
Signed-off-by: Denis Plotnikov <den-plotnikov@yandex-team.ru>
Message-Id: <20210325151217.262793-4-den-plotnikov@yandex-team.ru>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Commit 4bcad76f4c ("vhost-user-blk: delay vhost_user_blk_disconnect")
introduced postponing vhost_dev cleanup aiming to eliminate qemu aborts
because of connection problems with vhost-blk daemon.
However, it introdues a new problem. Now, any communication errors
during execution of vhost_dev_init() called by vhost_user_blk_device_realize()
lead to qemu abort on assert in vhost_dev_get_config().
This happens because vhost_user_blk_disconnect() is postponed but
it should have dropped s->connected flag by the time
vhost_user_blk_device_realize() performs a new connection opening.
On the connection opening, vhost_dev initialization in
vhost_user_blk_connect() relies on s->connection flag and
if it's not dropped, it skips vhost_dev initialization and returns
with success. Then, vhost_user_blk_device_realize()'s execution flow
goes to vhost_dev_get_config() where it's aborted on the assert.
To fix the problem this patch adds immediate cleanup on device
initialization(in vhost_user_blk_device_realize()) using different
event handlers for initialization and operation introduced in the
previous patch.
On initialization (in vhost_user_blk_device_realize()) we fully
control the initialization process. At that point, nobody can use the
device since it isn't initialized and we don't need to postpone any
cleanups, so we can do cleaup right away when there is a communication
problem with the vhost-blk daemon.
On operation we leave it as is, since the disconnect may happen when
the device is in use, so the device users may want to use vhost_dev's data
to do rollback before vhost_dev is re-initialized (e.g. in vhost_dev_set_log()).
Signed-off-by: Denis Plotnikov <den-plotnikov@yandex-team.ru>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Message-Id: <20210325151217.262793-3-den-plotnikov@yandex-team.ru>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
It is useful to use different connect/disconnect event handlers
on device initialization and operation as seen from the further
commit fixing a bug on device initialization.
This patch refactors the code to make use of them: we don't rely any
more on the VM state for choosing how to cleanup the device, instead
we explicitly use the proper event handler depending on whether
the device has been initialized.
Signed-off-by: Denis Plotnikov <den-plotnikov@yandex-team.ru>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Message-Id: <20210325151217.262793-2-den-plotnikov@yandex-team.ru>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Treat the num_queues field as virtio-endian. On big-endian hosts the
vhost-user-blk num_queues field was in the wrong endianness.
Move the blkcfg.num_queues store operation from realize to
vhost_user_blk_update_config() so feature negotiation has finished and
we know the endianness of the device. VIRTIO 1.0 devices are
little-endian, but in case someone wants to use legacy VIRTIO we support
all endianness cases.
Cc: qemu-stable@nongnu.org
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20210223144653.811468-2-stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Move the property types and property macros implemented in
qdev-properties-system.c to a new qdev-properties-system.h
header.
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Message-Id: <20201211220529.2290218-16-ehabkost@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Virtqueue has split and packed, so before setting inflight,
you need to inform the back-end virtqueue format.
Signed-off-by: Jin Yu <jin.yu@intel.com>
Acked-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Message-Id: <20201103123617.28256-1-jin.yu@intel.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This reverts commit adb29c0273.
The commit broke -device vhost-user-blk-pci because the
vhost_dev_prepare_inflight() function it introduced segfaults in
vhost_dev_set_features() when attempting to access struct vhost_dev's
vdev pointer before it has been assigned.
To reproduce the segfault simply launch a vhost-user-blk device with the
contrib vhost-user-blk device backend:
$ build/contrib/vhost-user-blk/vhost-user-blk -s /tmp/vhost-user-blk.sock -r -b /var/tmp/foo.img
$ build/qemu-system-x86_64 \
-device vhost-user-blk-pci,id=drv0,chardev=char1,addr=4.0 \
-object memory-backend-memfd,id=mem,size=1G,share=on \
-M memory-backend=mem,accel=kvm \
-chardev socket,id=char1,path=/tmp/vhost-user-blk.sock
Segmentation fault (core dumped)
Cc: Jin Yu <jin.yu@intel.com>
Cc: Raphael Norwitz <raphael.norwitz@nutanix.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20201102165709.232180-1-stefanha@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Virtqueue has split and packed, so before setting inflight,
you need to inform the back-end virtqueue format.
Signed-off-by: Jin Yu <jin.yu@intel.com>
Message-Id: <20200910134851.7817-1-jin.yu@intel.com>
Acked-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
vhost-user devices can get a disconnect in the middle of the VHOST-USER
handshake on the migration start. If disconnect event happened right
before sending next VHOST-USER command, then the vhost_dev_set_log()
call in the vhost_migration_log() function will return error. This error
will lead to the assert() and close the QEMU migration source process.
For the vhost-user devices the disconnect event should not break the
migration process, because:
- the device will be in the stopped state, so it will not be changed
during migration
- if reconnect will be made the migration log will be reinitialized as
part of reconnect/init process:
#0 vhost_log_global_start (listener=0x563989cf7be0)
at hw/virtio/vhost.c:920
#1 0x000056398603d8bc in listener_add_address_space (listener=0x563989cf7be0,
as=0x563986ea4340 <address_space_memory>)
at softmmu/memory.c:2664
#2 0x000056398603dd30 in memory_listener_register (listener=0x563989cf7be0,
as=0x563986ea4340 <address_space_memory>)
at softmmu/memory.c:2740
#3 0x0000563985fd6956 in vhost_dev_init (hdev=0x563989cf7bd8,
opaque=0x563989cf7e30, backend_type=VHOST_BACKEND_TYPE_USER,
busyloop_timeout=0)
at hw/virtio/vhost.c:1385
#4 0x0000563985f7d0b8 in vhost_user_blk_connect (dev=0x563989cf7990)
at hw/block/vhost-user-blk.c:315
#5 0x0000563985f7d3f6 in vhost_user_blk_event (opaque=0x563989cf7990,
event=CHR_EVENT_OPENED)
at hw/block/vhost-user-blk.c:379
Update the vhost-user-blk device with the internal started_vu field which
will be used for initialization (vhost_user_blk_start) and clean up
(vhost_user_blk_stop). This additional flag in the VhostUserBlk structure
will be used to track whether the device really needs to be stopped and
cleaned up on a vhost-user level.
The disconnect event will set the overall VHOST device (not vhost-user) to
the stopped state, so it can be used by the general vhost_migration_log
routine.
Such approach could be propogated to the other vhost-user devices, but
better idea is just to make the same connect/disconnect code for all the
vhost-user devices.
This migration issue was slightly discussed earlier:
- https://lists.gnu.org/archive/html/qemu-devel/2020-05/msg01509.html
- https://lists.gnu.org/archive/html/qemu-devel/2020-05/msg05241.html
Signed-off-by: Dima Stepanov <dimastep@yandex-team.ru>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Message-Id: <9fbfba06791a87813fcee3e2315f0b904cc6789a.1599813294.git.dimastep@yandex-team.ru>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Automatically size the number of request virtqueues to match the number
of vCPUs. This ensures that completion interrupts are handled on the
same vCPU that submitted the request. No IPI is necessary to complete
an I/O request and performance is improved. The maximum number of MSI-X
vectors and virtqueues limit are respected.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Message-Id: <20200818143348.310613-8-stefanha@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
We use the Object type all over the place.
Forward declare it in "qemu/typedefs.h".
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20200504115656.6045-2-f4bug@amsat.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
A socket write during vhost-user communication may trigger a disconnect
event, calling vhost_user_blk_disconnect() and clearing all the
vhost_dev structures holding data that vhost-user functions expect to
remain valid to roll back initialization correctly. Delay the cleanup to
keep vhost_dev structure valid.
There are two possible states to handle:
1. RUN_STATE_PRELAUNCH: skip bh oneshot call and perform disconnect in
the caller routine.
2. RUN_STATE_RUNNING: delay by using bh
BH changes are based on the similar changes for the vhost-user-net
device:
commit e7c83a885f
"vhost-user: delay vhost_user_stop"
Signed-off-by: Dima Stepanov <dimastep@yandex-team.ru>
Message-Id: <69b73b94dcd066065595266c852810e0863a0895.1590396396.git.dimastep@yandex-team.ru>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Li Feng <fengli@smartx.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Devices may have component devices and buses.
Device realization may fail. Realization is recursive: a device's
realize() method realizes its components, and device_set_realized()
realizes its buses (which should in turn realize the devices on that
bus, except bus_set_realized() doesn't implement that, yet).
When realization of a component or bus fails, we need to roll back:
unrealize everything we realized so far. If any of these unrealizes
failed, the device would be left in an inconsistent state. Must not
happen.
device_set_realized() lets it happen: it ignores errors in the roll
back code starting at label child_realize_fail.
Since realization is recursive, unrealization must be recursive, too.
But how could a partly failed unrealize be rolled back? We'd have to
re-realize, which can fail. This design is fundamentally broken.
device_set_realized() does not roll back at all. Instead, it keeps
unrealizing, ignoring further errors.
It can screw up even for a device with no buses: if the lone
dc->unrealize() fails, it still unregisters vmstate, and calls
listeners' unrealize() callback.
bus_set_realized() does not roll back either. Instead, it stops
unrealizing.
Fortunately, no unrealize method can fail, as we'll see below.
To fix the design error, drop parameter @errp from all the unrealize
methods.
Any unrealize method that uses @errp now needs an update. This leads
us to unrealize() methods that can fail. Merely passing it to another
unrealize method cannot cause failure, though. Here are the ones that
do other things with @errp:
* virtio_serial_device_unrealize()
Fails when qbus_set_hotplug_handler() fails, but still does all the
other work. On failure, the device would stay realized with its
resources completely gone. Oops. Can't happen, because
qbus_set_hotplug_handler() can't actually fail here. Pass
&error_abort to qbus_set_hotplug_handler() instead.
* hw/ppc/spapr_drc.c's unrealize()
Fails when object_property_del() fails, but all the other work is
already done. On failure, the device would stay realized with its
vmstate registration gone. Oops. Can't happen, because
object_property_del() can't actually fail here. Pass &error_abort
to object_property_del() instead.
* spapr_phb_unrealize()
Fails and bails out when remove_drcs() fails, but other work is
already done. On failure, the device would stay realized with some
of its resources gone. Oops. remove_drcs() fails only when
chassis_from_bus()'s object_property_get_uint() fails, and it can't
here. Pass &error_abort to remove_drcs() instead.
Therefore, no unrealize method can fail before this patch.
device_set_realized()'s recursive unrealization via bus uses
object_property_set_bool(). Can't drop @errp there, so pass
&error_abort.
We similarly unrealize with object_property_set_bool() elsewhere,
always ignoring errors. Pass &error_abort instead.
Several unrealize methods no longer handle errors from other unrealize
methods: virtio_9p_device_unrealize(),
virtio_input_device_unrealize(), scsi_qdev_unrealize(), ...
Much of the deleted error handling looks wrong anyway.
One unrealize methods no longer ignore such errors:
usb_ehci_pci_exit().
Several realize methods no longer ignore errors when rolling back:
v9fs_device_realize_common(), pci_qdev_unrealize(),
spapr_phb_realize(), usb_qdev_realize(), vfio_ccw_realize(),
virtio_device_realize().
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20200505152926.18877-17-armbru@redhat.com>
Several functions can't fail anymore: ich9_pm_add_properties(),
device_add_bootindex_property(), ppc_compat_add_property(),
spapr_caps_add_properties(), PropertyInfo.create(). Drop their @errp
parameter.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20200505152926.18877-16-armbru@redhat.com>
when s->inflight is freed, vhost_dev_free_inflight may try to access
s->inflight->addr, it will retrigger the following issue.
==7309==ERROR: AddressSanitizer: heap-use-after-free on address 0x604001020d18 at pc 0x555555ce948a bp 0x7fffffffb170 sp 0x7fffffffb160
READ of size 8 at 0x604001020d18 thread T0
#0 0x555555ce9489 in vhost_dev_free_inflight /root/smartx/qemu-el7/qemu-test/hw/virtio/vhost.c:1473
#1 0x555555cd86eb in virtio_reset /root/smartx/qemu-el7/qemu-test/hw/virtio/virtio.c:1214
#2 0x5555560d3eff in virtio_pci_reset hw/virtio/virtio-pci.c:1859
#3 0x555555f2ac53 in device_set_realized hw/core/qdev.c:893
#4 0x5555561d572c in property_set_bool qom/object.c:1925
#5 0x5555561de8de in object_property_set_qobject qom/qom-qobject.c:27
#6 0x5555561d99f4 in object_property_set_bool qom/object.c:1188
#7 0x555555e50ae7 in qdev_device_add /root/smartx/qemu-el7/qemu-test/qdev-monitor.c:626
#8 0x555555e51213 in qmp_device_add /root/smartx/qemu-el7/qemu-test/qdev-monitor.c:806
#9 0x555555e8ff40 in hmp_device_add /root/smartx/qemu-el7/qemu-test/hmp.c:1951
#10 0x555555be889a in handle_hmp_command /root/smartx/qemu-el7/qemu-test/monitor.c:3404
#11 0x555555beac8b in monitor_command_cb /root/smartx/qemu-el7/qemu-test/monitor.c:4296
#12 0x555556433eb7 in readline_handle_byte util/readline.c:393
#13 0x555555be89ec in monitor_read /root/smartx/qemu-el7/qemu-test/monitor.c:4279
#14 0x5555563285cc in tcp_chr_read chardev/char-socket.c:470
#15 0x7ffff670b968 in g_main_context_dispatch (/lib64/libglib-2.0.so.0+0x4a968)
#16 0x55555640727c in glib_pollfds_poll util/main-loop.c:215
#17 0x55555640727c in os_host_main_loop_wait util/main-loop.c:238
#18 0x55555640727c in main_loop_wait util/main-loop.c:497
#19 0x555555b2d0bf in main_loop /root/smartx/qemu-el7/qemu-test/vl.c:2013
#20 0x555555b2d0bf in main /root/smartx/qemu-el7/qemu-test/vl.c:4776
#21 0x7fffdd2eb444 in __libc_start_main (/lib64/libc.so.6+0x22444)
#22 0x555555b3767a (/root/smartx/qemu-el7/qemu-test/x86_64-softmmu/qemu-system-x86_64+0x5e367a)
0x604001020d18 is located 8 bytes inside of 40-byte region [0x604001020d10,0x604001020d38)
freed by thread T0 here:
#0 0x7ffff6f00508 in __interceptor_free (/lib64/libasan.so.4+0xde508)
#1 0x7ffff671107d in g_free (/lib64/libglib-2.0.so.0+0x5007d)
previously allocated by thread T0 here:
#0 0x7ffff6f00a88 in __interceptor_calloc (/lib64/libasan.so.4+0xdea88)
#1 0x7ffff6710fc5 in g_malloc0 (/lib64/libglib-2.0.so.0+0x4ffc5)
SUMMARY: AddressSanitizer: heap-use-after-free /root/smartx/qemu-el7/qemu-test/hw/virtio/vhost.c:1473 in vhost_dev_free_inflight
Shadow bytes around the buggy address:
0x0c08801fc150: fa fa 00 00 00 00 04 fa fa fa fd fd fd fd fd fa
0x0c08801fc160: fa fa fd fd fd fd fd fd fa fa 00 00 00 00 04 fa
0x0c08801fc170: fa fa 00 00 00 00 00 01 fa fa 00 00 00 00 04 fa
0x0c08801fc180: fa fa 00 00 00 00 00 01 fa fa 00 00 00 00 00 01
0x0c08801fc190: fa fa 00 00 00 00 00 fa fa fa 00 00 00 00 04 fa
=>0x0c08801fc1a0: fa fa fd[fd]fd fd fd fa fa fa fd fd fd fd fd fa
0x0c08801fc1b0: fa fa fd fd fd fd fd fa fa fa fd fd fd fd fd fa
0x0c08801fc1c0: fa fa 00 00 00 00 00 fa fa fa fd fd fd fd fd fd
0x0c08801fc1d0: fa fa 00 00 00 00 00 01 fa fa fd fd fd fd fd fa
0x0c08801fc1e0: fa fa fd fd fd fd fd fa fa fa fd fd fd fd fd fd
0x0c08801fc1f0: fa fa 00 00 00 00 00 01 fa fa fd fd fd fd fd fa
Shadow byte legend (one shadow byte represents 8 application bytes):
Addressable: 00
Partially addressable: 01 02 03 04 05 06 07
Heap left redzone: fa
Freed heap region: fd
Stack left redzone: f1
Stack mid redzone: f2
Stack right redzone: f3
Stack after return: f5
Stack use after scope: f8
Global redzone: f9
Global init order: f6
Poisoned by user: f7
Container overflow: fc
Array cookie: ac
Intra object redzone: bb
ASan internal: fe
Left alloca redzone: ca
Right alloca redzone: cb
==7309==ABORTING
Signed-off-by: Li Feng <fengli@smartx.com>
Message-Id: <20200417101707.14467-1-fengli@smartx.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
the G_IO_HUP is watched in tcp_chr_connect, and the callback
vhost_user_blk_watch is not needed, because tcp_chr_hup is registered as
callback. And it will close the tcp link.
Signed-off-by: Li Feng <fengli@smartx.com>
Message-Id: <20200323052924.29286-1-fengli@smartx.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
use the new virtio_delete_queue function to cleanup.
Signed-off-by: Pan Nengyuan <pannengyuan@huawei.com>
Message-Id: <20200224041336.30790-3-pannengyuan@huawei.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
virtio queues forgot to delete in unrealize, and aslo error path in
realize, this patch fix these memleaks, the leak stack is as follow:
Direct leak of 114688 byte(s) in 16 object(s) allocated from:
#0 0x7f24024fdbf0 in calloc (/lib64/libasan.so.3+0xcabf0)
#1 0x7f2401642015 in g_malloc0 (/lib64/libglib-2.0.so.0+0x50015)
#2 0x55ad175a6447 in virtio_add_queue /mnt/sdb/qemu/hw/virtio/virtio.c:2327
#3 0x55ad17570cf9 in vhost_user_blk_device_realize /mnt/sdb/qemu/hw/block/vhost-user-blk.c:419
#4 0x55ad175a3707 in virtio_device_realize /mnt/sdb/qemu/hw/virtio/virtio.c:3509
#5 0x55ad176ad0d1 in device_set_realized /mnt/sdb/qemu/hw/core/qdev.c:876
#6 0x55ad1781ff9d in property_set_bool /mnt/sdb/qemu/qom/object.c:2080
#7 0x55ad178245ae in object_property_set_qobject /mnt/sdb/qemu/qom/qom-qobject.c:26
#8 0x55ad17821eb4 in object_property_set_bool /mnt/sdb/qemu/qom/object.c:1338
#9 0x55ad177aeed7 in virtio_pci_realize /mnt/sdb/qemu/hw/virtio/virtio-pci.c:1801
Reported-by: Euler Robot <euler.robot@huawei.com>
Signed-off-by: Pan Nengyuan <pannengyuan@huawei.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20200224041336.30790-2-pannengyuan@huawei.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
The Chardev events are listed in the QEMUChrEvent enum.
By using the enum in the IOEventHandler typedef we:
- make the IOEventHandler type more explicit (this handler
process out-of-band information, while the IOReadHandler
is in-band),
- help static code analyzers.
This patch was produced with the following spatch script:
@match@
expression backend, opaque, context, set_open;
identifier fd_can_read, fd_read, fd_event, be_change;
@@
qemu_chr_fe_set_handlers(backend, fd_can_read, fd_read, fd_event,
be_change, opaque, context, set_open);
@depends on match@
identifier opaque, event;
identifier match.fd_event;
@@
static
-void fd_event(void *opaque, int event)
+void fd_event(void *opaque, QEMUChrEvent event)
{
...
}
Then the typedef was modified manually in
include/chardev/char-fe.h.
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Acked-by: Corey Minyard <cminyard@mvista.com>
Acked-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20191218172009.8868-15-philmd@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The Chardev events are listed in the QEMUChrEvent enum. To be
able to use this enum in the IOEventHandler typedef, we need to
explicit all the events ignored by this frontend, to silent the
following GCC warning:
CC s390x-softmmu/hw/block/vhost-user-blk.o
hw/block/vhost-user-blk.c: In function ‘vhost_user_blk_event’:
hw/block/vhost-user-blk.c:370:5: error: enumeration value ‘CHR_EVENT_BREAK’ not handled in switch [-Werror=switch]
370 | switch (event) {
| ^~~~~~
hw/block/vhost-user-blk.c:370:5: error: enumeration value ‘CHR_EVENT_MUX_IN’ not handled in switch [-Werror=switch]
hw/block/vhost-user-blk.c:370:5: error: enumeration value ‘CHR_EVENT_MUX_OUT’ not handled in switch [-Werror=switch]
cc1: all warnings being treated as errors
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20191218172009.8868-10-philmd@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Same rational as: e6cc11d64f
Of the 3 virtqueues, seabios only sets cmd, leaving ctrl
and event without a physical address. This can cause
vhost_verify_ring_part_mapping to return ENOMEM, causing
the following logs:
qemu-system-x86_64: Unable to map available ring for ring 0
qemu-system-x86_64: Verify ring failure on region 0
This has already been fixed for vhost scsi devices and was
recently vhost-user scsi devices. This commit fixes it for
vhost-user-blk devices.
Suggested-by: Phillippe Mathieu-Daude <philmd@redhat.com>
Signed-off-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Message-Id: <1566498865-55506-1-git-send-email-raphael.norwitz@nutanix.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>
