Hanna Czenczek <hreitz@redhat.com> noted that the array index in
virtio_blk_dma_restart_cb() is not bounds-checked:
g_autofree VirtIOBlockReq **vq_rq = g_new0(VirtIOBlockReq *, num_queues);
...
while (rq) {
VirtIOBlockReq *next = rq->next;
uint16_t idx = virtio_get_queue_index(rq->vq);
rq->next = vq_rq[idx];
^^^^^^^^^^
The code is correct because both rq->vq and vq_rq[] depend on
num_queues, but this is indirect and not 100% obvious. Add an assertion.
Suggested-by: Hanna Czenczek <hreitz@redhat.com>
Reviewed-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20240206190610.107963-4-stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
It is not possible to instantiate a virtio-blk device with 0 virtqueues.
The following check is located in ->realize():
if (!conf->num_queues) {
error_setg(errp, "num-queues property must be larger than 0");
return;
}
Later on we access s->vq_aio_context[0] under the assumption that there
is as least one virtqueue. Hanna Czenczek <hreitz@redhat.com> noted that
it would help to show that the array index is already valid.
Add an assertion to document that s->vq_aio_context[0] is always
safe...and catch future code changes that break this assumption.
Suggested-by: Hanna Czenczek <hreitz@redhat.com>
Reviewed-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20240206190610.107963-3-stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Hanna Czenczek <hreitz@redhat.com> noticed that the safety of
`vq_aio_context[vq->value] = ctx;` with user-defined vq->value inputs is
not obvious.
The code is structured in validate() + apply() steps so input validation
is there, but it happens way earlier and there is nothing that
guarantees apply() can only be called with validated inputs.
This patch moves the validate() call inside the apply() function so
validation is guaranteed. I also added the bounds checking assertion
that Hanna suggested.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
Message-ID: <20240206190610.107963-2-stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
In cases where a device tries to read more bytes than the block device
contains, the error is vague: "device requires X bytes, block backend
provides Y bytes".
This patch changes the errors of this function to include the block
backend name, the device id and device type name where appropriate.
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
Message-id: 7260eadff22c08457740117c1bb7bd2b4353acb9.1706598705.git.manos.pitsidianakis@linaro.org
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
The following expression is incorrect because blk_pread_nonzeroes()
deals in units of bytes, not sectors:
bytes = MIN(size - offset, BDRV_REQUEST_MAX_SECTORS)
^^^^^^^
BDRV_REQUEST_MAX_BYTES is the appropriate constant.
Fixes: a4b15a8b9e ("pflash: Only read non-zero parts of backend image")
Cc: Xiang Zheng <zhengxiang9@huawei.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-id: 20240130002712.257815-1-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
When starting ioeventfd it is common practice to set the event notifier
so that the ioeventfd handler is triggered to run immediately. There may
be no requests waiting to be processed, but the idea is that if a
request snuck in then we guarantee that it will be detected.
One scenario where self-triggering the ioeventfd is necessary is when
virtio_blk_handle_output() is called from a vCPU thread before the
VIRTIO Device Status transitions to DRIVER_OK. In that case we need to
self-trigger the ioeventfd so that the kick handled by the vCPU thread
causes the vq AioContext thread to take over handling the request(s).
Fixes: b6948ab01d ("virtio-blk: add iothread-vq-mapping parameter")
Reported-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20240119135748.270944-7-stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
We no longer rely on setting the AioContext since the block layer
IO_CODE APIs can be called from any thread. Now it's just a hint to help
block jobs and other operations co-locate themselves in a thread with
the guest I/O requests. Keep going if setting the AioContext fails.
Suggested-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20240119135748.270944-6-stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
A virtio-blk device with the iothread-vq-mapping parameter has
per-virtqueue AioContexts. It is not thread-safe to process s->rq
requests in the BlockBackend AioContext since that may be different from
the virtqueue's AioContext to which this request belongs. The code
currently races and could crash.
Adapt virtio_blk_dma_restart_cb() to first split s->rq into per-vq lists
and then schedule a BH each vq's AioContext as necessary. This way
requests are safely processed in their vq's AioContext.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20240119135748.270944-5-stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The dataplane code is really about using ioeventfd. It's used both for
IOThreads (what we think of as dataplane) and for the core virtio-pci
code's ioeventfd feature (which is enabled by default and used when no
IOThread has been specified). Rename the code to reflect this.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20240119135748.270944-4-stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
virtio_blk_data_plane_create() and virtio_blk_data_plane_destroy() are
actually about s->vq_aio_context[] rather than managing
dataplane-specific state.
As a prerequisite to using s->vq_aio_context[] in all code paths (even
when dataplane is not used), rename these functions to reflect that they
just manage s->vq_aio_context and call them regardless of whether or not
dataplane is in use.
Note that virtio-blk supports running with -device
virtio-blk-pci,ioevent=off where the vCPU thread enters the device
emulation code. In this mode ioeventfd is not used for virtqueue
processing. However, we still want to initialize s->vq_aio_context[] to
qemu_aio_context in that case since I/O completion callbacks will be
invoked in the main loop thread.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20240119135748.270944-3-stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The dataplane code used to be significantly different from the
non-dataplane code and therefore had a separate source file.
Over time the difference has gotten smaller because the I/O code paths
were unified. Nowadays the distinction between the VirtIOBlock and
VirtIOBlockDataPlane structs is more of an inconvenience that hinders
code simplification.
Move hw/block/dataplane/virtio-blk.c into hw/block/virtio-blk.c, merging
VirtIOBlockDataPlane's fields into VirtIOBlock.
hw/block/virtio-blk.c used VirtIOBlock->dataplane to check if
virtio_blk_data_plane_create() was successful. This is not necessary
because ->dataplane_started and ->dataplane_disabled can be used
instead. This patch makes those changes in order to drop
VirtIOBlock->dataplane.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20240119135748.270944-2-stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Add an update buffer where all block updates are staged.
Flush or discard updates properly, so we should never see
half-completed block writes in pflash storage.
Drop a bunch of FIXME comments ;)
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20240108160900.104835-4-kraxel@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Use the helper functions we have to read/write multi-byte values
in correct byte order.
Suggested-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20240108160900.104835-3-kraxel@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Move the offset calculation, do it once at the start of the function and
let the 'p' variable point directly to the memory location which should
be updated. This makes it simpler to update other buffers than
pfl->storage in an upcoming patch. No functional change.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20240108160900.104835-2-kraxel@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
The 16MiB flash device is only used by the deprecated shix machine.
Its code it old and unmaintained, and has never been adapted to the
QOM architecture. It still contains debug statements and uses global
variables. It is time to deprecate it.
Signed-off-by: Samuel Tardieu <sam@rfc1149.net>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20240109083053.2581588-3-sam@rfc1149.net>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
The term "QEMU global mutex" is identical to the more widely used Big
QEMU Lock ("BQL"). Update the code comments and documentation to use
"BQL" instead of "QEMU global mutex".
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Acked-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Paul Durrant <paul@xen.org>
Reviewed-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Harsh Prateek Bora <harshpb@linux.ibm.com>
Message-id: 20240102153529.486531-6-stefanha@redhat.com
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>
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>
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>
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>
Coverity couldn't see that nr_existing was always going to be zero when
qemu_xen_xs_directory() returned NULL in the ENOENT case (CID 1523906).
Perhaps more to the point, neither could Peter at first glance. Improve
the code to hopefully make it clearer to Coverity and human reviewers
alike.
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>
There's no need to force the user to assign a vdev. We can automatically
assign one, starting at xvda and searching until we find the first disk
name that's unused.
This means we can now allow '-drive if=xen,file=xxx' to work without an
explicit separate -driver argument, just like if=virtio.
Rip out the legacy handling from the xenpv machine, which was scribbling
over any disks configured by the toolstack, and didn't work with anything
but raw images.
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Acked-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Paul Durrant <paul@xen.org>
Even on x86_64 the default protocol is the x86-32 one if the guest doesn't
specifically ask for x86-64.
Cc: qemu-stable@nongnu.org
Fixes: b6af8926fb ("xen: add implementations of xen-block connect and disconnect functions...")
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>
There is a batching mechanism for virtio-blk Used Buffer Notifications
that is no longer needed because the previous commit added batching to
virtio_notify_irqfd().
Note that this mechanism was rarely used in practice because it is only
enabled when EVENT_IDX is not negotiated by the driver. Modern drivers
enable EVENT_IDX.
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20230913200045.1024233-5-stefanha@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The networking subsystem may wish to use defer_call(), so move the code
to util/ where it can be reused.
As a reminder of what defer_call() does:
This API defers a function call within a defer_call_begin()/defer_call_end()
section, allowing multiple calls to batch up. This is a performance
optimization that is used in the block layer to submit several I/O requests
at once instead of individually:
defer_call_begin(); <-- start of section
...
defer_call(my_func, my_obj); <-- deferred my_func(my_obj) call
defer_call(my_func, my_obj); <-- another
defer_call(my_func, my_obj); <-- another
...
defer_call_end(); <-- end of section, my_func(my_obj) is called once
Suggested-by: Ilya Maximets <i.maximets@ovn.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20230913200045.1024233-3-stefanha@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Prepare to move the blk_io_plug_call() API out of the block layer so
that other subsystems call use this deferred call mechanism. Rename it
to defer_call() but leave the code in block/plug.c.
The next commit will move the code out of the block layer.
Suggested-by: Ilya Maximets <i.maximets@ovn.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Paul Durrant <paul@xen.org>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20230913200045.1024233-2-stefanha@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
infrastructure for vhost-vdpa shadow work
piix south bridge rework
reconnect for vhost-user-scsi
dummy ACPI QTG DSM for cxl
tests, cleanups, fixes all over the place
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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Merge tag 'for_upstream' of https://git.kernel.org/pub/scm/virt/kvm/mst/qemu into staging
virtio,pc,pci: features, cleanups
infrastructure for vhost-vdpa shadow work
piix south bridge rework
reconnect for vhost-user-scsi
dummy ACPI QTG DSM for cxl
tests, cleanups, fixes all over the place
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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# gpg: Good signature from "Michael S. Tsirkin <mst@kernel.org>" [full]
# gpg: aka "Michael S. Tsirkin <mst@redhat.com>" [full]
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* tag 'for_upstream' of https://git.kernel.org/pub/scm/virt/kvm/mst/qemu: (62 commits)
intel-iommu: Report interrupt remapping faults, fix return value
MAINTAINERS: Add include/hw/intc/i8259.h to the PC chip section
vhost-user: Fix protocol feature bit conflict
tests/acpi: Update DSDT.cxl with QTG DSM
hw/cxl: Add QTG _DSM support for ACPI0017 device
tests/acpi: Allow update of DSDT.cxl
hw/i386/cxl: ensure maxram is greater than ram size for calculating cxl range
vhost-user: fix lost reconnect
vhost-user-scsi: start vhost when guest kicks
vhost-user-scsi: support reconnect to backend
vhost: move and rename the conn retry times
vhost-user-common: send get_inflight_fd once
hw/i386/pc_piix: Make PIIX4 south bridge usable in PC machine
hw/isa/piix: Implement multi-process QEMU support also for PIIX4
hw/isa/piix: Resolve duplicate code regarding PCI interrupt wiring
hw/isa/piix: Reuse PIIX3's PCI interrupt triggering in PIIX4
hw/isa/piix: Rename functions to be shared for PCI interrupt triggering
hw/isa/piix: Reuse PIIX3 base class' realize method in PIIX4
hw/isa/piix: Share PIIX3's base class with PIIX4
hw/isa/piix: Harmonize names of reset control memory regions
...
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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>
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>
Update the IWM/ISM register block decoding to match the description given in the
"SWIM Chip Users Reference". This allows us to validate the device response to
the guest OS which currently only does just enough to indicate that the floppy
drive is unavailable.
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Message-ID: <20231004083806.757242-14-mark.cave-ayland@ilande.co.uk>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
The swim chip provides an implementation of both Apple's IWM and ISM floppy disk
controllers. Split the existing implementation into separate register banks for
each controller, whilst also switching the IWM registers from 16-bit to 8-bit
as implemented in real hardware.
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Message-ID: <20231004083806.757242-13-mark.cave-ayland@ilande.co.uk>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Local variables shadowing other local variables or parameters make the
code needlessly hard to understand. Tracked down with -Wshadow=local.
Clean up: delete inner declarations when they are actually redundant,
else rename variables.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Acked-by: Anthony PERARD <anthony.perard@citrix.com>
Acked-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-ID: <20230921121312.1301864-7-armbru@redhat.com>
It will help in getting rid of some drive_get(IF_MTD) calls by
retrieving the BlockBackend directly from the m25p80 device.
Cc: Alistair Francis <alistair@alistair23.me>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Commit 1898293990 ("xen-block: Use specific blockdev driver")
introduced a new error path, without taking care of allocated
resources.
So only allocate the qdicts after the error check, and free both
`filename` and `driver` when we are about to return and thus taking
care of both success and error path.
Coverity only spotted the leak of qdicts (*_layer variables).
Reported-by: Peter Maydell <peter.maydell@linaro.org>
Fixes: Coverity CID 1508722, 1398649
Fixes: 1898293990 ("xen-block: Use specific blockdev driver")
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Reviewed-by: Paul Durrant <paul@xen.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20230704171819.42564-1-anthony.perard@citrix.com>
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
The main loop thread can consume 100% CPU when using --device
virtio-blk-pci,iothread=<iothread>. ppoll() constantly returns but
reading virtqueue host notifiers fails with EAGAIN. The file descriptors
are stale and remain registered with the AioContext because of bugs in
the virtio-blk dataplane start/stop code.
The problem is that the dataplane start/stop code involves drain
operations, which call virtio_blk_drained_begin() and
virtio_blk_drained_end() at points where the host notifier is not
operational:
- In virtio_blk_data_plane_start(), blk_set_aio_context() drains after
vblk->dataplane_started has been set to true but the host notifier has
not been attached yet.
- In virtio_blk_data_plane_stop(), blk_drain() and blk_set_aio_context()
drain after the host notifier has already been detached but with
vblk->dataplane_started still set to true.
I would like to simplify ->ioeventfd_start/stop() to avoid interactions
with drain entirely, but couldn't find a way to do that. Instead, this
patch accepts the fragile nature of the code and reorders it so that
vblk->dataplane_started is false during drain operations. This way the
virtio_blk_drained_begin() and virtio_blk_drained_end() calls don't
touch the host notifier. The result is that
virtio_blk_data_plane_start() and virtio_blk_data_plane_stop() have
complete control over the host notifier and stale file descriptors are
no longer left in the AioContext.
This patch fixes the 100% CPU consumption in the main loop thread and
correctly moves host notifier processing to the IOThread.
Fixes: 1665d9326f ("virtio-blk: implement BlockDevOps->drained_begin()")
Reported-by: Lukáš Doktor <ldoktor@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Tested-by: Lukas Doktor <ldoktor@redhat.com>
Message-id: 20230704151527.193586-1-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Slave/master nomenclature was replaced with backend/frontend in commit
1fc19b6527 ("vhost-user: Adopt new backend naming")
This patch replaces all remaining uses of master and slave in the
codebase.
Signed-off-by: Emmanouil Pitsidianakis <manos.pitsidianakis@linaro.org>
Message-Id: <20230613080849.2115347-1-manos.pitsidianakis@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
The previous commit remove the unnecessary "virtio-access.h"
header. These files no longer have target-specific dependency.
Move them to the generic 'softmmu_ss' source set.
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20230524093744.88442-11-philmd@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
None of these files use the VirtIO Load/Store API declared
by "hw/virtio/virtio-access.h". This header probably crept
in via copy/pasting, remove it.
Note, "virtio-access.h" is target-specific, so any file
including it also become tainted as target-specific.
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Acked-by: Richard Henderson <richard.henderson@linaro.org>
Tested-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20230524093744.88442-10-philmd@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
We use the user_ss[] array to hold the user emulation sources,
and the softmmu_ss[] array to hold the system emulation ones.
Hold the latter in the 'system_ss[]' array for parity with user
emulation.
Mechanical change doing:
$ sed -i -e s/softmmu_ss/system_ss/g $(git grep -l softmmu_ss)
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20230613133347.82210-10-philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Introduce a new API for thread-local blk_io_plug() that does not
traverse the block graph. The goal is to make blk_io_plug() multi-queue
friendly.
Instead of having block drivers track whether or not we're in a plugged
section, provide an API that allows them to defer a function call until
we're unplugged: blk_io_plug_call(fn, opaque). If blk_io_plug_call() is
called multiple times with the same fn/opaque pair, then fn() is only
called once at the end of the function - resulting in batching.
This patch introduces the API and changes blk_io_plug()/blk_io_unplug().
blk_io_plug()/blk_io_unplug() no longer require a BlockBackend argument
because the plug state is now thread-local.
Later patches convert block drivers to blk_io_plug_call() and then we
can finally remove .bdrv_co_io_plug() once all block drivers have been
converted.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Acked-by: Kevin Wolf <kwolf@redhat.com>
Message-id: 20230530180959.1108766-2-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Detach ioeventfds during drained sections to stop I/O submission from
the guest. virtio-blk is no longer reliant on aio_disable_external()
after this patch. This will allow us to remove the
aio_disable_external() API once all other code that relies on it is
converted.
Take extra care to avoid attaching/detaching ioeventfds if the data
plane is started/stopped during a drained section. This should be rare,
but maybe the mirror block job can trigger it.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20230516190238.8401-18-stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
virtio_queue_aio_detach_host_notifier() does two things:
1. It removes the fd handler from the event loop.
2. It processes the virtqueue one last time.
The first step can be peformed by any thread and without taking the
AioContext lock.
The second step may need the AioContext lock (depending on the device
implementation) and runs in the thread where request processing takes
place. virtio-blk and virtio-scsi therefore call
virtio_queue_aio_detach_host_notifier() from a BH that is scheduled in
AioContext.
The next patch will introduce a .drained_begin() function that needs to
call virtio_queue_aio_detach_host_notifier(). .drained_begin() functions
cannot call aio_poll() to wait synchronously for the BH. It is possible
for a .drained_poll() callback to asynchronously wait for the BH, but
that is more complex than necessary here.
Move the virtqueue processing out to the callers of
virtio_queue_aio_detach_host_notifier() so that the function can be
called from any thread. This is in preparation for the next patch.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20230516190238.8401-17-stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Detach event channels during drained sections to stop I/O submission
from the ring. xen-block is no longer reliant on aio_disable_external()
after this patch. This will allow us to remove the
aio_disable_external() API once all other code that relies on it is
converted.
Extend xen_device_set_event_channel_context() to allow ctx=NULL. The
event channel still exists but the event loop does not monitor the file
descriptor. Event channel processing can resume by calling
xen_device_set_event_channel_context() with a non-NULL ctx.
Factor out xen_device_set_event_channel_context() calls in
hw/block/dataplane/xen-block.c into attach/detach helper functions.
Incidentally, these don't require the AioContext lock because
aio_set_fd_handler() is thread-safe.
It's safer to register BlockDevOps after the dataplane instance has been
created. The BlockDevOps .drained_begin/end() callbacks depend on the
dataplane instance, so move the blk_set_dev_ops() call after
xen_block_dataplane_create().
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20230516190238.8401-12-stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
