Next patches will register the vhost_vdpa memory listener while the VM
is migrating at the destination, so we can map the memory to the device
before stopping the VM at the source. The main goal is to reduce the
downtime.
However, the destination QEMU is unaware of which vhost_vdpa device will
register its memory_listener. If the source guest has CVQ enabled, it
will be the CVQ device. Otherwise, it will be the first one.
Move the file descriptor to VhostVDPAShared so all vhost_vdpa can use
it, rather than always in the first / last vhost_vdpa.
Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20231221174322.3130442-7-eperezma@redhat.com>
Tested-by: Lei Yang <leiyang@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
By the end of this series dma_map and dma_unmap functions don't have the
vdpa device for tracing. Movinge trace function to shared member one.
Print it also in the vdpa initialization so log reader can relate them.
Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20231221174322.3130442-6-eperezma@redhat.com>
Tested-by: Lei Yang <leiyang@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Next patches will register the vhost_vdpa memory listener while the VM
is migrating at the destination, so we can map the memory to the device
before stopping the VM at the source. The main goal is to reduce the
downtime.
However, the destination QEMU is unaware of which vhost_vdpa device will
register its memory_listener. If the source guest has CVQ enabled, it
will be the CVQ device. Otherwise, it will be the first one.
Move the shadow_data member to VhostVDPAShared so all vhost_vdpa can use
it, rather than always in the first or last vhost_vdpa.
Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20231221174322.3130442-5-eperezma@redhat.com>
Tested-by: Lei Yang <leiyang@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Next patches will register the vhost_vdpa memory listener while the VM
is migrating at the destination, so we can map the memory to the device
before stopping the VM at the source. The main goal is to reduce the
downtime.
However, the destination QEMU is unaware of which vhost_vdpa device will
register its memory_listener. If the source guest has CVQ enabled, it
will be the CVQ device. Otherwise, it will be the first one.
Move the iova range to VhostVDPAShared so all vhost_vdpa can use it,
rather than always in the first or last vhost_vdpa.
Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20231221174322.3130442-4-eperezma@redhat.com>
Tested-by: Lei Yang <leiyang@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Next patches will register the vhost_vdpa memory listener while the VM
is migrating at the destination, so we can map the memory to the device
before stopping the VM at the source. The main goal is to reduce the
downtime.
However, the destination QEMU is unaware of which vhost_vdpa device will
register its memory_listener. If the source guest has CVQ enabled, it
will be the CVQ device. Otherwise, it will be the first one.
Move the iova tree to VhostVDPAShared so all vhost_vdpa can use it,
rather than always in the first or last vhost_vdpa.
Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20231221174322.3130442-3-eperezma@redhat.com>
Tested-by: Lei Yang <leiyang@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
It will hold properties shared among all vhost_vdpa instances associated
with of the same device. For example, we just need one iova_tree or one
memory listener for the entire device.
Next patches will register the vhost_vdpa memory listener at the
beginning of the VM migration at the destination. This enables QEMU to
map the memory to the device before stopping the VM at the source,
instead of doing while both source and destination are stopped, thus
minimizing the downtime.
However, the destination QEMU is unaware of which vhost_vdpa struct will
register its memory_listener. If the source guest has CVQ enabled, it
will be the one associated with the CVQ. Otherwise, it will be the
first one.
Save the memory operations related members in a common place rather than
always in the first / last vhost_vdpa.
Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20231221174322.3130442-2-eperezma@redhat.com>
Tested-by: Lei Yang <leiyang@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Next commits will set DRIVER and ACKNOWLEDGE flags repeatedly in the
case of a migration destination. Let's save ioctls with this.
Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Message-Id: <20231215172830.2540987-2-eperezma@redhat.com>
Virtio-gpu malloc memory for the queue when it realized, but the queues was not
released when it unrealized, which resulting in a memory leak. In addition,
vm_change_state_handler is not cleaned up, which is related to vdev and will
lead to segmentation fault when VM shutdown.
Signed-off-by: wangmeiling <wangmeiling21@huawei.com>
Signed-off-by: Binfeng Wu <wubinfeng@huawei.com>
Message-Id: <7bbbc0f3-2ad9-83ca-b39b-f976d0837daf@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
It is required to use error_report() instead of error_reportf_err(), if the
prior function does not take local_err as the argument. As a result, the
local_err is always NULL and segment fault may happen.
vhost_scsi_start()
-> vhost_scsi_set_endpoint(s) --> does not allocate local_err
-> error_reportf_err()
-> error_vprepend()
-> g_string_append(newmsg, (*errp)->msg) --> (*errp) is NULL
In addition, add ": " at the end of other error_reportf_err() logs.
Fixes: 7962e432b4 ("vhost-user-scsi: support reconnect to backend")
Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
Message-Id: <20231214003117.43960-1-dongli.zhang@oracle.com>
Reviewed-by: Feng Li <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>
If a vcpu with an apic-id that is not supported by the legacy
interface (>255) is hot-plugged, the legacy code will dynamically switch
to the modern interface. However, the hotplug event is not forwarded to
the new interface resulting in the vcpu not being fully/properly added
to the machine config. This BUG is evidenced by OVMF when it
it attempts to count the vcpus and reports an inconsistent vcpu count
reported by the fw_cfg interface and the modern hotpug interface.
Fix is to propagate the hotplug event after making the switch from
the legacy interface to the modern interface.
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Aaron Young <aaron.young@oracle.com>
Message-Id: <0e8a9baebbb29f2a6c87fd08e43dc2ac4019759a.1702398644.git.Aaron.Young@oracle.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This adds support for vhost-scsi to be able to create a worker thread
per virtqueue. Right now for vhost-net we get a worker thread per
tx/rx virtqueue pair which scales nicely as we add more virtqueues and
CPUs, but for scsi we get the single worker thread that's shared by all
virtqueues. When trying to send IO to more than 2 virtqueues the single
thread becomes a bottlneck.
This patch adds a new setting, worker_per_virtqueue, which can be set
to:
false: Existing behavior where we get the single worker thread.
true: Create a worker per IO virtqueue.
Signed-off-by: Mike Christie <michael.christie@oracle.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20231204231618.21962-3-michael.christie@oracle.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>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
This adds the vhost backend callouts for the worker ioctls added in the
6.4 linux kernel commit:
c1ecd8e95007 ("vhost: allow userspace to create workers")
Signed-off-by: Mike Christie <michael.christie@oracle.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20231204231618.21962-2-michael.christie@oracle.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>
In fact, type4-count, core-count, core-count2, thread-count and
thread-count2 are tested with KVM not TCG.
Rename these test functions to reflect KVM base instead of TCG.
Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
Message-Id: <20231127160202.1037290-1-zhao1.liu@linux.intel.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Since the driver doesn't support interrupts, we must return early when
index is set to VIRTIO_CONFIG_IRQ_IDX. Basically the same thing Viresh
did for "91208dd297f2 virtio: i2c: Check notifier helpers for
VIRTIO_CONFIG_IRQ_IDX".
Fixes: 544f0278af ("virtio: introduce macro VIRTIO_CONFIG_IRQ_IDX")
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Message-Id: <20231025171841.3379663-1-mathieu.poirier@linaro.org>
Tested-by: Leo Yan <leo.yan@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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Merge tag 'pull-loongarch-20231221' of https://gitlab.com/gaosong/qemu into staging
pull-loongarch-20231221
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# gpg: Signature made Thu 21 Dec 2023 03:09:33 EST
# gpg: using RSA key B8FF1DA0D2FDCB2DA09C6C2C40A2FFF239263EDF
# gpg: Good signature from "Song Gao <m17746591750@163.com>" [unknown]
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* tag 'pull-loongarch-20231221' of https://gitlab.com/gaosong/qemu:
target/loongarch: Add timer information dump support
hw/loongarch/virt: Align high memory base address with super page size
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Add the iothread-vq-mapping parameter to assign virtqueues to IOThreads.
Store the vq:AioContext mapping in the new struct
VirtIOBlockDataPlane->vq_aio_context[] field and refactor the code to
use the per-vq AioContext instead of the BlockDriverState's AioContext.
Reimplement --device virtio-blk-pci,iothread= and non-IOThread mode by
assigning all virtqueues to the IOThread and main loop's AioContext in
vq_aio_context[], respectively.
The comment in struct VirtIOBlockDataPlane about EventNotifiers is
stale. Remove it.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20231220134755.814917-5-stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
virtio-blk and virtio-scsi devices will need a way to specify the
mapping between IOThreads and virtqueues. At the moment all virtqueues
are assigned to a single IOThread or the main loop. This single thread
can be a CPU bottleneck, so it is necessary to allow finer-grained
assignment to spread the load.
Introduce DEFINE_PROP_IOTHREAD_VQ_MAPPING_LIST() so devices can take a
parameter that maps virtqueues to IOThreads. The command-line syntax for
this new property is as follows:
--device '{"driver":"foo","iothread-vq-mapping":[{"iothread":"iothread0","vqs":[0,1,2]},...]}'
IOThreads are specified by name and virtqueues are specified by 0-based
index.
It will be common to simply assign virtqueues round-robin across a set
of IOThreads. A convenient syntax that does not require specifying
individual virtqueue indices is available:
--device '{"driver":"foo","iothread-vq-mapping":[{"iothread":"iothread0"},{"iothread":"iothread1"},...]}'
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20231220134755.814917-4-stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
qdev_alias_all_properties() aliases a DeviceState's qdev properties onto
an Object. This is used for VirtioPCIProxy types so that --device
virtio-blk-pci has properties of its embedded --device virtio-blk-device
object.
Currently this function is implemented using qdev properties. Change the
function to use QOM object class properties instead. This works because
qdev properties create QOM object class properties, but it also catches
any QOM object class-only properties that have no qdev properties.
This change ensures that properties of devices are shown with --device
foo,\? even if they are QOM object class properties.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20231220134755.814917-2-stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
StringOutputVisitor crashes when it visits a struct because
->start_struct() is NULL.
Show "<omitted>" instead of crashing. This is necessary because the
virtio-blk-pci iothread-vq-mapping parameter that I'd like to introduce
soon is a list of IOThreadMapping structs.
This patch is a quick fix to solve the crash, but the long-term solution
is replacing StringOutputVisitor with something that can handle the full
gamut of values in QEMU.
Cc: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20231212134934.500289-1-stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Use qemu_get_current_aio_context() in mixed wrappers and coroutine
wrappers so that code runs in the caller's AioContext instead of moving
to the BlockDriverState's AioContext. This change is necessary for the
multi-queue block layer where any thread can call into the block layer.
Most wrappers are IO_CODE where it's safe to use the current AioContext
nowadays. BlockDrivers and the core block layer use their own locks and
no longer depend on the AioContext lock for thread-safety.
The bdrv_create() wrapper invokes GLOBAL_STATE code. Using the current
AioContext is safe because this code is only called with the BQL held
from the main loop thread.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20230912231037.826804-6-stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The AioContext lock no longer exists.
There is one noteworthy change:
- * More specifically, these functions use BDRV_POLL_WHILE(bs), which
- * requires the caller to be either in the main thread and hold
- * the BlockdriverState (bs) AioContext lock, or directly in the
- * home thread that runs the bs AioContext. Calling them from
- * another thread in another AioContext would cause deadlocks.
+ * More specifically, these functions use BDRV_POLL_WHILE(bs), which requires
+ * the caller to be either in the main thread or directly in the home thread
+ * that runs the bs AioContext. Calling them from another thread in another
+ * AioContext would cause deadlocks.
I am not sure whether deadlocks are still possible. Maybe they have just
moved to the fine-grained locks that have replaced the AioContext. Since
I am not sure if the deadlocks are gone, I have kept the substance
unchanged and just removed mention of the AioContext.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-ID: <20231205182011.1976568-15-stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The AioContext lock no longer exists.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-ID: <20231205182011.1976568-14-stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The SCSI subsystem no longer uses the AioContext lock. Request
processing runs exclusively in the BlockBackend's AioContext since
"scsi: only access SCSIDevice->requests from one thread" and hence the
lock is unnecessary.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-ID: <20231205182011.1976568-13-stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Encourage the use of locking primitives and stop mentioning the
AioContext lock since it is being removed.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-ID: <20231205182011.1976568-12-stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Delete these functions because nothing calls these functions anymore.
I introduced these APIs in commit 98563fc3ec ("aio: add
aio_context_acquire() and aio_context_release()") in 2014. It's with a
sigh of relief that I delete these APIs almost 10 years later.
Thanks to Paolo Bonzini's vision for multi-queue QEMU, we got an
understanding of where the code needed to go in order to remove the
limitations that the original dataplane and the IOThread/AioContext
approach that followed it.
Emanuele Giuseppe Esposito had the splendid determination to convert
large parts of the codebase so that they no longer needed the AioContext
lock. This was a painstaking process, both in the actual code changes
required and the iterations of code review that Emanuele eked out of
Kevin and me over many months.
Kevin Wolf tackled multitudes of graph locking conversions to protect
in-flight I/O from run-time changes to the block graph as well as the
clang Thread Safety Analysis annotations that allow the compiler to
check whether the graph lock is being used correctly.
And me, well, I'm just here to add some pizzazz to the QEMU multi-queue
block layer :). Thank you to everyone who helped with this effort,
including Eric Blake, code reviewer extraordinaire, and others who I've
forgotten to mention.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-ID: <20231205182011.1976568-11-stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Now that the AioContext lock no longer exists, AIO_WAIT_WHILE() and
AIO_WAIT_WHILE_UNLOCKED() are equivalent.
A future patch will get rid of AIO_WAIT_WHILE_UNLOCKED().
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-ID: <20231205182011.1976568-10-stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The AioContext lock no longer has any effect. Remove it.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-ID: <20231205182011.1976568-9-stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The bdrv_co_lock() and bdrv_co_unlock() functions are already no-ops.
Remove them.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20231205182011.1976568-8-stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This is the big patch that removes
aio_context_acquire()/aio_context_release() from the block layer and
affected block layer users.
There isn't a clean way to split this patch and the reviewers are likely
the same group of people, so I decided to do it in one patch.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Paul Durrant <paul@xen.org>
Message-ID: <20231205182011.1976568-7-stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Stop acquiring/releasing the AioContext lock in
bdrv_graph_wrlock()/bdrv_graph_unlock() since the lock no longer has any
effect.
The distinction between bdrv_graph_wrunlock() and
bdrv_graph_wrunlock_ctx() becomes meaningless and they can be collapsed
into one function.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-ID: <20231205182011.1976568-6-stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
aio_context_acquire()/aio_context_release() has been replaced by
fine-grained locking to protect state shared by multiple threads. The
AioContext lock still plays the role of balancing locking in
AIO_WAIT_WHILE() and many functions in QEMU either require that the
AioContext lock is held or not held for this reason. In other words, the
AioContext lock is purely there for consistency with itself and serves
no real purpose anymore.
Stop actually acquiring/releasing the lock in
aio_context_acquire()/aio_context_release() so that subsequent patches
can remove callers across the codebase incrementally.
I have performed "make check" and qemu-iotests stress tests across
x86-64, ppc64le, and aarch64 to confirm that there are no failures as a
result of eliminating the lock.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Acked-by: Kevin Wolf <kwolf@redhat.com>
Message-ID: <20231205182011.1976568-5-stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The aio_context_acquire() API is being removed. Drop the test case that
calls the API.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-ID: <20231205182011.1976568-4-stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Since the removal of AioContext locking, the correctness of the code
relies on running requests from a single AioContext at any given time.
Add assertions that verify that callbacks are invoked in the correct
AioContext.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20231205182011.1976568-3-stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Protect the Task Management Function BH state with a lock. The TMF BH
runs in the main loop thread. An IOThread might process a TMF at the
same time as the TMF BH is running. Therefore tmf_bh_list and tmf_bh
must be protected by a lock.
Run TMF request completion in the IOThread using aio_wait_bh_oneshot().
This avoids more locking to protect the virtqueue and SCSI layer state.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-ID: <20231205182011.1976568-2-stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Commit abfcd2760b ("dma-helpers: prevent dma_blk_cb() vs
dma_aio_cancel() race") acquired the AioContext lock inside dma_blk_cb()
to avoid a race with scsi_device_purge_requests() running in the main
loop thread.
The SCSI code no longer calls dma_aio_cancel() from the main loop thread
while I/O is running in the IOThread AioContext. Therefore it is no
longer necessary to take this lock to protect DMAAIOCB fields. The
->cb() function also does not require the lock because blk_aio_*() and
friends do not need the AioContext lock.
Both hw/ide/core.c and hw/ide/macio.c also call dma_blk_io() but don't
rely on it taking the AioContext lock, so this change is safe.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-ID: <20231204164259.1515217-5-stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
blk_aio_*() doesn't require the AioContext lock and the SCSI subsystem's
internal state also does not anymore.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Acked-by: Kevin Wolf <kwolf@redhat.com>
Message-ID: <20231204164259.1515217-4-stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
virtio_queue_aio_attach_host_notifier() does not require the AioContext
lock. Stop taking the lock and add an explicit smp_wmb() because we were
relying on the implicit barrier in the AioContext lock before.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-ID: <20231204164259.1515217-3-stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Stop depending on the AioContext lock and instead access
SCSIDevice->requests from only one thread at a time:
- When the VM is running only the BlockBackend's AioContext may access
the requests list.
- When the VM is stopped only the main loop may access the requests
list.
These constraints protect the requests list without the need for locking
in the I/O code path.
Note that multiple IOThreads are not supported yet because the code
assumes all SCSIRequests are executed from a single AioContext. Leave
that as future work.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-ID: <20231204164259.1515217-2-stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
We have a few test cases that include tests for corner case aspects of
internal snapshots, but nothing that tests that they actually function
as snapshots or that involves deleting a snapshot. Add a test for this
kind of basic internal snapshot functionality.
The error cases include a regression test for the crash we just fixed
with snapshot operations on inactive images.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-ID: <20231201142520.32255-4-kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Currently, the conflict between -incoming and -loadvm is only detected
when loading the snapshot fails because the image is still inactive for
the incoming migration. This results in a suboptimal error message:
$ ./qemu-system-x86_64 -hda /tmp/test.qcow2 -loadvm foo -incoming defer
qemu-system-x86_64: Device 'ide0-hd0' is writable but does not support snapshots
Catch the situation already in qemu_validate_options() to improve the
message:
$ ./qemu-system-x86_64 -hda /tmp/test.qcow2 -loadvm foo -incoming defer
qemu-system-x86_64: 'incoming' and 'loadvm' options are mutually exclusive
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-ID: <20231201142520.32255-3-kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
bdrv_is_read_only() only checks if the node is configured to be
read-only eventually, but even if it returns false, writing to the node
may not be permitted at the moment (because it's inactive).
bdrv_is_writable() checks that the node can be written to right now, and
this is what the snapshot operations really need.
Change bdrv_can_snapshot() to use bdrv_is_writable() to fix crashes like
the following:
$ ./qemu-system-x86_64 -hda /tmp/test.qcow2 -loadvm foo -incoming defer
qemu-system-x86_64: ../block/io.c:1990: int bdrv_co_write_req_prepare(BdrvChild *, int64_t, int64_t, BdrvTrackedRequest *, int): Assertion `!(bs->open_flags & BDRV_O_INACTIVE)' failed.
The resulting error message after this patch isn't perfect yet, but at
least it doesn't crash any more:
$ ./qemu-system-x86_64 -hda /tmp/test.qcow2 -loadvm foo -incoming defer
qemu-system-x86_64: Device 'ide0-hd0' is writable but does not support snapshots
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-ID: <20231201142520.32255-2-kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
There is no need to acquire the AioContext lock around blk_aio_*() or
blk_get_geometry() anymore. I/O plugging (defer_call()) also does not
require the AioContext lock anymore.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20230914140101.1065008-5-stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Nothing in the completion code path relies on the AioContext lock
anymore. Virtqueues are only accessed from one thread at any moment and
the s->rq global state is protected by its own lock now.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20230914140101.1065008-4-stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
s->rq is accessed from IO_CODE and GLOBAL_STATE_CODE. Introduce a lock
to protect s->rq and eliminate reliance on the AioContext lock.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20230914140101.1065008-3-stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The file-posix block driver currently only sets up Linux AIO and
io_uring in the BDS's AioContext. In the multi-queue block layer we must
be able to submit I/O requests in AioContexts that do not have Linux AIO
and io_uring set up yet since any thread can call into the block driver.
Set up Linux AIO and io_uring for the current AioContext during request
submission. We lose the ability to return an error from
.bdrv_file_open() when Linux AIO and io_uring setup fails (e.g. due to
resource limits). Instead the user only gets warnings and we fall back
to aio=threads. This is still better than a fatal error after startup.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20230914140101.1065008-2-stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
NBDClient has a number of fields that are accessed by both the export
AioContext and the main loop thread. When the AioContext lock is removed
these fields will need another form of protection.
Add NBDClient->lock and protect fields that are accessed by both
threads. Also add assertions where possible and otherwise add doc
comments stating assumptions about which thread and lock holding.
Note this patch moves the client->recv_coroutine assertion from
nbd_co_receive_request() to nbd_trip() where client->lock is held.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20231221192452.1785567-7-stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The NBD clients list is currently accessed from both the export
AioContext and the main loop thread. When the AioContext lock is removed
there will be nothing protecting the clients list.
Adding a lock around the clients list is tricky because NBDClient
structs are refcounted and may be freed from the export AioContext or
the main loop thread. nbd_export_request_shutdown() -> client_close() ->
nbd_client_put() is also tricky because the list lock would be held
while indirectly dropping references to NDBClients.
A simpler approach is to only allow nbd_client_put() and client_close()
calls from the main loop thread. Then the NBD clients list is only
accessed from the main loop thread and no fancy locking is needed.
nbd_trip() just needs to reschedule itself in the main loop AioContext
before calling nbd_client_put() and client_close(). This costs more CPU
cycles per NBD request so add nbd_client_put_nonzero() to optimize the
common case where more references to NBDClient remain.
Note that nbd_client_get() can still be called from either thread, so
make NBDClient->refcount atomic.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20231221192452.1785567-6-stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
nbd_trip() processes a single NBD request from start to finish and holds
an NBDClient reference throughout. NBDRequest does not outlive the scope
of nbd_trip(). Therefore it is unnecessary to ref/unref NBDClient for
each NBDRequest.
Removing these nbd_client_get()/nbd_client_put() calls will make
thread-safety easier in the commits that follow.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <20231221192452.1785567-5-stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Timer emulation sometimes is problematic especially when vm is running in
kvm mode. This patch adds registers dump support relative with timer
hardware, so that it is easier to find the problems.
Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Reviewed-by: Song Gao <gaosong@loongson.cn>
Message-Id: <20231206081839.2290178-1-maobibo@loongson.cn>
Signed-off-by: Song Gao <gaosong@loongson.cn>
