In the case where a SCSI layer transfer is incorrectly terminated, it is
possible for a TI command to cause a SCSI buffer overflow due to the
expected transfer data length being less than the available data in the
FIFO. When this occurs the unsigned async_len variable underflows and
becomes a large offset which writes past the end of the allocated SCSI
buffer.
Restrict the non-DMA transfer length to be the smallest of the expected
transfer length and the available FIFO data to ensure that it is no longer
possible for the SCSI buffer overflow to occur.
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1810
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-ID: <20230913204410.65650-3-mark.cave-ayland@ilande.co.uk>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The call to esp_dma_enable() was being made with the SYSBUS_ESP type instead of
the ESP type. This meant that when GPIO 1 was being used to trigger a DMA
request from an external DMA controller, the setting of ESPState's dma_enabled
field would clobber unknown memory whilst the dma_cb callback pointer would
typically return NULL so the DMA request would never start.
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-ID: <20230913204410.65650-2-mark.cave-ayland@ilande.co.uk>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
We are doing things like
nb_sectors /= (s->qdev.blocksize / BDRV_SECTOR_SIZE);
in the code here (e.g. in scsi_disk_emulate_mode_sense()), so if
the blocksize is smaller than BDRV_SECTOR_SIZE (=512), this crashes
with a division by 0 exception. Thus disallow block sizes of 256
bytes to avoid this situation.
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1813
CVE: 2023-42467
Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-ID: <20230925091854.49198-1-thuth@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
scsi_clear_unit_attention() now only handles REPORTED LUNS DATA HAS
CHANGED.
This only happens when we handle REPORT LUNS commands, so let's rename
the function in scsi_clear_reported_luns_changed() and call it only in
scsi_target_emulate_report_luns().
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Message-ID: <20230712134352.118655-4-sgarzare@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The previous commit moved the unit attention clearing when we create
the request. So now we can clean scsi_clear_unit_attention() to handle
only the case of the REPORT LUNS command: this is the only case in
which a UNIT ATTENTION is cleared without having been reported.
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Message-ID: <20230712134352.118655-3-sgarzare@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Commit 1880ad4f4e ("virtio-scsi: Batched prepare for cmd reqs") split
calls to scsi_req_new() and scsi_req_enqueue() in the virtio-scsi device.
No ill effects were observed until commit 8cc5583abe ("virtio-scsi: Send
"REPORTED LUNS CHANGED" sense data upon disk hotplug events") added a
unit attention that was easy to trigger with device hotplug and
hot-unplug.
Because the two calls were separated, all requests in the batch were
prepared calling scsi_req_new() to report a sense. The first one
submitted would report the right sense and reset it to NO_SENSE, while
the others reported CHECK_CONDITION with no sense data. This caused
SCSI errors in Linux.
To solve this issue, let's fetch the unit attention as early as possible
when we prepare the request, so that only the first request in the batch
will use the unit attention SCSIReqOps and the others will not report
CHECK CONDITION.
Fixes: 1880ad4f4e ("virtio-scsi: Batched prepare for cmd reqs")
Fixes: 8cc5583abe ("virtio-scsi: Send "REPORTED LUNS CHANGED" sense data upon disk hotplug events")
Reported-by: Thomas Huth <thuth@redhat.com>
Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=2176702
Co-developed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Message-ID: <20230712134352.118655-2-sgarzare@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
virtio_scsi_dataplane_stop() calls blk_drain_all(), which invokes
->drained_begin()/->drained_end() after we've already detached the host
notifier. virtio_scsi_drained_end() currently attaches the host notifier
again and leaves it dangling after dataplane has stopped.
This results in the following assertion failure because
virtio_scsi_defer_to_dataplane() is called from the IOThread instead of
the main loop thread:
qemu-system-x86_64: ../softmmu/memory.c:1111: memory_region_transaction_commit: Assertion `qemu_mutex_iothread_locked()' failed.
Buglink: https://gitlab.com/qemu-project/qemu/-/issues/1680
Reported-by: Jean-Louis Dupond <jean-louis@dupond.be>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20230611193924.2444914-1-stefanha@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@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>
Following the SCSI variable named '[specific_]scsi_ss', rename the
target-specific VirtIO/SCSI set prefixed with 'specific_'. This will
help when adding target-agnostic VirtIO/SCSI set in few commits.
No logical change.
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20230524093744.88442-5-philmd@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
We will modify this file shortly. Re-arrange it slightly first,
declaring source sets first.
No logical change.
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20230524093744.88442-4-philmd@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Instead of adding 'vhost-scsi-common.c' twice (for VHOST_SCSI and
VHOST_USER_SCSI), have it depend on VHOST_SCSI_COMMON, selected by
both symbols.
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20230524093744.88442-3-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>
GCC9 is confused when building with CFLAG -O3:
hw/scsi/megasas.c: In function ‘megasas_scsi_realize’:
hw/scsi/megasas.c:2387:26: error: duplicated ‘if’ condition [-Werror=duplicated-cond]
2387 | } else if (s->fw_sge >= 128 - MFI_PASS_FRAME_SIZE) {
hw/scsi/megasas.c:2385:19: note: previously used here
2385 | if (s->fw_sge >= MEGASAS_MAX_SGE - MFI_PASS_FRAME_SIZE) {
cc1: all warnings being treated as errors
When this device was introduced in commit e8f943c3bc, the author
cared about modularity, using a definition for the firmware limit.
However if the firmware limit isn't changed (MEGASAS_MAX_SGE = 128),
the code ends doing the same check twice.
Per the maintainer [*]:
> The original code assumed that one could change MFI_PASS_FRAME_SIZE,
> but it turned out not to be possible as it's being hardcoded in the
> drivers themselves (even though the interface provides mechanisms to
> query it). So we can remove the duplicate lines.
Add the 'MEGASAS_MIN_SGE' definition for the '64' magic value,
slightly rewrite the condition check to simplify a bit the logic
and remove the unnecessary / duplicated check.
[*] https://lore.kernel.org/qemu-devel/e0029fc5-882f-1d63-15e3-1c3dbe9b6a2c@suse.de/
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Message-Id: <20230328210126.16282-1-philmd@linaro.org>
Mechanical change running Coccinelle spatch with content
generated from the qom-cast-macro-clean-cocci-gen.py added
in the previous commit.
Suggested-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20230601093452.38972-3-philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Thomas Huth <thuth@redhat.com>
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>
The virtio-scsi Host Bus Adapter provides access to devices on a SCSI
bus. Those SCSI devices typically have a BlockBackend. When the
BlockBackend enters a drained section, the SCSI device must temporarily
stop submitting new I/O requests.
Implement this behavior by temporarily stopping virtio-scsi virtqueue
processing when one of the SCSI devices enters a drained section. The
new scsi_device_drained_begin() API allows scsi-disk to message the
virtio-scsi HBA.
scsi_device_drained_begin() uses a drain counter so that multiple SCSI
devices can have overlapping drained sections. The HBA only sees one
pair of .drained_begin/end() calls.
After this commit, virtio-scsi no longer depends on hw/virtio's
ioeventfd aio_set_event_notifier(is_external=true). This commit is a
step towards removing the aio_disable_external() API.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20230516190238.8401-19-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>
This patch is part of an effort to remove the aio_disable_external()
API because it does not fit in a multi-queue block layer world where
many AioContexts may be submitting requests to the same disk.
The SCSI emulation code is already in good shape to stop using
aio_disable_external(). It was only used by commit 9c5aad84da
("virtio-scsi: fixed virtio_scsi_ctx_check failed when detaching scsi
disk") to ensure that virtio_scsi_hotunplug() works while the guest
driver is submitting I/O.
Ensure virtio_scsi_hotunplug() is safe as follows:
1. qdev_simple_device_unplug_cb() -> qdev_unrealize() ->
device_set_realized() calls qatomic_set(&dev->realized, false) so
that future scsi_device_get() calls return NULL because they exclude
SCSIDevices with realized=false.
That means virtio-scsi will reject new I/O requests to this
SCSIDevice with VIRTIO_SCSI_S_BAD_TARGET even while
virtio_scsi_hotunplug() is still executing. We are protected against
new requests!
2. scsi_qdev_unrealize() already contains a call to
scsi_device_purge_requests() so that in-flight requests are cancelled
synchronously. This ensures that no in-flight requests remain once
qdev_simple_device_unplug_cb() returns.
Thanks to these two conditions we don't need aio_disable_external()
anymore.
Cc: Zhengui Li <lizhengui@huawei.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Daniil Tatianin <d-tatianin@yandex-team.ru>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20230516190238.8401-5-stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Only report a transport reset event to the guest after the SCSIDevice
has been unrealized by qdev_simple_device_unplug_cb().
qdev_simple_device_unplug_cb() sets the SCSIDevice's qdev.realized field
to false so that scsi_device_find/get() no longer see it.
scsi_target_emulate_report_luns() also needs to be updated to filter out
SCSIDevices that are unrealized.
Change virtio_scsi_push_event() to take event information as an argument
instead of the SCSIDevice. This allows virtio_scsi_hotunplug() to emit a
VIRTIO_SCSI_T_TRANSPORT_RESET event after the SCSIDevice has already
been unrealized.
These changes ensure that the guest driver does not see the SCSIDevice
that's being unplugged if it responds very quickly to the transport
reset event.
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Daniil Tatianin <d-tatianin@yandex-team.ru>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20230516190238.8401-4-stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Add a helper function to check whether the device is realized without
requiring the Big QEMU Lock. The next patch adds a second caller. The
goal is to avoid spreading DeviceState field accesses throughout the
code.
Suggested-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20230516190238.8401-3-stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
We cannot use the generic reentrancy guard in the LSI code, so
we have to manually prevent endless reentrancy here. The problematic
lsi_execute_script() function has already a way to detect whether
too many instructions have been executed - we just have to slightly
change the logic here that it also takes into account if the function
has been called too often in a reentrant way.
The code in fuzz-lsi53c895a-test.c has been taken from an earlier
patch by Mauro Matteo Cascella.
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1563
Message-Id: <20230522091011.1082574-1-thuth@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Alexander Bulekov <alxndr@bu.edu>
Signed-off-by: Thomas Huth <thuth@redhat.com>
While trying to use a SCSI disk on the LSI controller with an
older version of Fedora (25), I'm getting:
qemu: warning: Blocked re-entrant IO on MemoryRegion: lsi-mmio at addr: 0x34
and the SCSI controller is not usable. Seems like we have to
disable the reentrancy checker for the MMIO region, too, to
get this working again.
The problem could be reproduced it like this:
./qemu-system-x86_64 -accel kvm -m 2G -machine q35 \
-device lsi53c810,id=lsi1 -device scsi-hd,drive=d0 \
-drive if=none,id=d0,file=.../somedisk.qcow2 \
-cdrom Fedora-Everything-netinst-i386-25-1.3.iso
Where somedisk.qcow2 is an image that contains already some partitions
and file systems.
In the boot menu of Fedora, go to
"Troubleshooting" -> "Rescue a Fedora system" -> "3) Skip to shell"
Then check "dmesg | grep -i 53c" for failure messages, and try to mount
a partition from somedisk.qcow2.
Message-Id: <20230516090556.553813-1-thuth@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
Using linux 6.x guest, at boot time, an inquiry on a scsi-generic
device makes qemu crash. This is caused by a buffer overflow when
scsi-generic patches the block limits VPD page.
Do the operations on a temporary on-stack buffer that is guaranteed
to be large enough.
Reported-by: Théo Maillart <tmaillart@freebox.fr>
Analyzed-by: Théo Maillart <tmaillart@freebox.fr>
Cc: qemu-stable@nongnu.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
There is no need for the AioContext lock in aio_wait_bh_oneshot().
It's easy to remove the lock from existing callers and then switch from
AIO_WAIT_WHILE() to AIO_WAIT_WHILE_UNLOCKED() in aio_wait_bh_oneshot().
Document that the AioContext lock should not be held across
aio_wait_bh_oneshot(). Holding a lock across aio_poll() can cause
deadlock so we don't want callers to do that.
This is a step towards getting rid of the AioContext lock.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20230404153307.458883-1-stefanha@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
As the code is designed to use the memory APIs to access the script ram,
disable reentrancy checks for the pseudo-RAM ram_io MemoryRegion.
In the future, ram_io may be converted from an IO to a proper RAM MemoryRegion.
Reported-by: Fiona Ebner <f.ebner@proxmox.com>
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Message-Id: <20230427211013.2994127-6-alxndr@bu.edu>
Signed-off-by: Thomas Huth <thuth@redhat.com>
This protects devices from bh->mmio reentrancy issues.
Thanks: Thomas Huth <thuth@redhat.com> for diagnosing OS X test failure.
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Paul Durrant <paul@xen.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20230427211013.2994127-5-alxndr@bu.edu>
Signed-off-by: Thomas Huth <thuth@redhat.com>
Bring the files in line with the QEMU coding style, with spaces
for indentation.
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/378
Signed-off-by: Yeqi Fu <fufuyqqqqqq@gmail.com>
Message-Id: <20230315032649.57568-1-fufuyqqqqqq@gmail.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
The Free Software Foundation moved to a new address and some
sources in QEMU referred to their old location.
The address should be updated and replaced by a pointer to
<https://www.gnu.org/licenses/>
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/379
Signed-off-by: Khadija Kamran <kkamran.bese16seecs@seecs.edu.pk>
Message-Id: <576ee9203fdac99d7251a98faa66b9ce1e7febc5.1675941486.git.kkamran.bese16seecs@seecs.edu.pk>
Reviewed-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Thomas Huth <thuth@redhat.com>
When an IOThread is configured, the ctrl virtqueue is processed in the
IOThread. TMFs that reset SCSI devices are currently called directly
from the IOThread and trigger an assertion failure in blk_drain() from
the following call stack:
virtio_scsi_handle_ctrl_req -> virtio_scsi_do_tmf -> device_code_reset
-> scsi_disk_reset -> scsi_device_purge_requests -> blk_drain
../block/block-backend.c:1780: void blk_drain(BlockBackend *): Assertion `qemu_in_main_thread()' failed.
The blk_drain() function is not designed to be called from an IOThread
because it needs the Big QEMU Lock (BQL).
This patch defers TMFs that reset SCSI devices to a Bottom Half (BH)
that runs in the main loop thread under the BQL. This way it's safe to
call blk_drain() and the assertion failure is avoided.
Introduce s->tmf_bh_list for tracking TMF requests that have been
deferred to the BH. When the BH runs it will grab the entire list and
process all requests. Care must be taken to clear the list when the
virtio-scsi device is reset or unrealized. Otherwise deferred TMF
requests could execute later and lead to use-after-free or other
undefined behavior.
The s->resetting counter that's used by TMFs that reset SCSI devices is
accessed from multiple threads. This patch makes that explicit by using
atomic accessor functions. With this patch applied the counter is only
modified by the main loop thread under the BQL but can be read by any
thread.
Reported-by: Qing Wang <qinwang@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20230221212218.1378734-4-stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
dma_blk_cb() only takes the AioContext lock around ->io_func(). That
means the rest of dma_blk_cb() is not protected. In particular, the
DMAAIOCB field accesses happen outside the lock.
There is a race when the main loop thread holds the AioContext lock and
invokes scsi_device_purge_requests() -> bdrv_aio_cancel() ->
dma_aio_cancel() while an IOThread executes dma_blk_cb(). The dbs->acb
field determines how cancellation proceeds. If dma_aio_cancel() sees
dbs->acb == NULL while dma_blk_cb() is still running, the request can be
completed twice (-ECANCELED and the actual return value).
The following assertion can occur with virtio-scsi when an IOThread is
used:
../hw/scsi/scsi-disk.c:368: scsi_dma_complete: Assertion `r->req.aiocb != NULL' failed.
Fix the race by holding the AioContext across dma_blk_cb(). Now
dma_aio_cancel() under the AioContext lock will not see
inconsistent/intermediate states.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20230221212218.1378734-3-stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
If requests are being processed in the IOThread when a SCSIDevice is
unplugged, scsi_device_purge_requests() -> scsi_req_cancel_async() races
with I/O completion callbacks. Both threads load and store req->aiocb.
This can lead to assert(r->req.aiocb == NULL) failures and undefined
behavior.
Protect r->req.aiocb with the AioContext lock to prevent the race.
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20230221212218.1378734-2-stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
BlockDriver->bdrv_getlength is categorized as IO callback, and it
currently doesn't run in a coroutine. We should let it take a graph
rdlock since the callback traverses the block nodes graph, which however
is only possible in a coroutine.
Therefore turn it into a co_wrapper to move the actual function into a
coroutine where the lock can be taken.
Because now this function creates a new coroutine and polls, we need to
take the AioContext lock where it is missing, for the only reason that
internally co_wrapper calls AIO_WAIT_WHILE and it expects to release the
AioContext lock.
This is especially messy when a co_wrapper creates a coroutine and polls
in bdrv_open_driver, because this function has so many callers in so
many context that it can easily lead to deadlocks. Therefore the new
rule for bdrv_open_driver is that the caller must always hold the
AioContext lock of the given bs (except if it is a coroutine), because
the function calls bdrv_refresh_total_sectors() which is now a
co_wrapper.
Once the rwlock is ultimated and placed in every place it needs to be,
we will poll using AIO_WAIT_WHILE_UNLOCKED and remove the AioContext
lock.
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20230113204212.359076-7-kwolf@redhat.com>
Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This is below memleak detected when to quit the qemu-system-x86_64 (with
vhost-scsi-pci).
(qemu) quit
=================================================================
==15568==ERROR: LeakSanitizer: detected memory leaks
Direct leak of 40 byte(s) in 1 object(s) allocated from:
#0 0x7f00aec57917 in __interceptor_calloc (/lib64/libasan.so.6+0xb4917)
#1 0x7f00ada0d7b5 in g_malloc0 (/lib64/libglib-2.0.so.0+0x517b5)
#2 0x5648ffd38bac in vhost_scsi_start ../hw/scsi/vhost-scsi.c:92
#3 0x5648ffd38d52 in vhost_scsi_set_status ../hw/scsi/vhost-scsi.c:131
#4 0x5648ffda340e in virtio_set_status ../hw/virtio/virtio.c:2036
#5 0x5648ff8de281 in virtio_ioport_write ../hw/virtio/virtio-pci.c:431
#6 0x5648ff8deb29 in virtio_pci_config_write ../hw/virtio/virtio-pci.c:576
#7 0x5648ffe5c0c2 in memory_region_write_accessor ../softmmu/memory.c:493
#8 0x5648ffe5c424 in access_with_adjusted_size ../softmmu/memory.c:555
#9 0x5648ffe6428f in memory_region_dispatch_write ../softmmu/memory.c:1515
#10 0x5648ffe8613d in flatview_write_continue ../softmmu/physmem.c:2825
#11 0x5648ffe86490 in flatview_write ../softmmu/physmem.c:2867
#12 0x5648ffe86d9f in address_space_write ../softmmu/physmem.c:2963
#13 0x5648ffe86e57 in address_space_rw ../softmmu/physmem.c:2973
#14 0x5648fffbfb3d in kvm_handle_io ../accel/kvm/kvm-all.c:2639
#15 0x5648fffc0e0d in kvm_cpu_exec ../accel/kvm/kvm-all.c:2890
#16 0x5648fffc90a7 in kvm_vcpu_thread_fn ../accel/kvm/kvm-accel-ops.c:51
#17 0x56490042400a in qemu_thread_start ../util/qemu-thread-posix.c:505
#18 0x7f00ac3b6ea4 in start_thread (/lib64/libpthread.so.0+0x7ea4)
Free the vsc->inflight at the 'stop' path.
Fixes: b82526c7ee ("vhost-scsi: support inflight io track")
Cc: Joe Jin <joe.jin@oracle.com>
Cc: Li Feng <fengli@smartx.com>
Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
Message-Id: <20230104160433.21353-1-dongli.zhang@oracle.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
PCIDeviceClass and PCIDevice are defined in pci.h. Many users of the
header don't actually need them. Similar structs live in their own
headers: PCIBusClass and PCIBus in pci_bus.h, PCIBridge in
pci_bridge.h, PCIHostBridgeClass and PCIHostState in pci_host.h,
PCIExpressHost in pcie_host.h, and PCIERootPortClass, PCIEPort, and
PCIESlot in pcie_port.h.
Move PCIDeviceClass and PCIDeviceClass to new pci_device.h, along with
the code that needs them. Adjust include directives.
This also enables the next commit.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20221222100330.380143-6-armbru@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
hw/pci/pci_bridge.h and hw/cxl/cxl.h include each other.
Fortunately, breaking the loop is merely a matter of deleting
unnecessary includes from headers, and adding them back in places
where they are now missing.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20221222100330.380143-2-armbru@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
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>
Those typos are in files which are used to generate the QEMU manual.
Signed-off-by: Stefan Weil <sw@weilnetz.de>
Message-Id: <20221110190825.879620-1-sw@weilnetz.de>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Ani Sinha <ani@anisinha.ca>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
[thuth: update sentence in can.rst as suggested by Peter]
Signed-off-by: Thomas Huth <thuth@redhat.com>
Currently the vwm_pvscsi controller resets individual SCSI devices
with the device_legacy_reset() function. The only difference between
this and device_cold_reset() is that device_legacy_reset() resets the
device but not any child qbuses it might have.
In this case, no SCSI device has a child qbus, so the functions have
the same behaviour. Switch to device_cold_reset() to move away from
using the deprecated function, and bring this SCSI controller in to
line with what all the others do.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20221013160623.1296109-3-peter.maydell@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
In the SCSI subsystem we currently use the legacy functions
qdev_reset_all() and qbus_reset_all(). These perform a recursive
reset, starting from either a qbus or a qdev. However they do not
permit any of the devices in the tree to use three-phase reset,
because device reset goes through the device_legacy_reset() function
that only calls the single DeviceClass::reset method.
Switch to using the device_cold_reset() and bus_cold_reset()
functions. These also perform a recursive reset, where first the
children are reset and then finally the parent, but they use the new
(...in 2020...) Resettable mechanism, which supports both the old
style single-reset method and also the new 3-phase reset handling.
Since no devices attached to SCSI buses currently try to use 3-phase
reset, this should be a no-behaviour-change commit which just reduces
the use of a deprecated API.
Commit created with:
sed -i -e 's/qdev_reset_all/device_cold_reset/g;s/qbus_reset_all/bus_cold_reset/g' hw/scsi/*.c
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20221013160623.1296109-2-peter.maydell@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Section 5.6.6.3 of VirtIO specification states, "Events will also
be reported via sense codes..." However, no sense data is sent when
VIRTIO_SCSI_EVT_RESET_RESCAN or VIRTIO_SCSI_EVT_RESET_REMOVED events
are reported (when disk hotplug/hotunplug events occur). SCSI layer
on Solaris depends on this sense data, and hence does not handle disk
hotplug/hotunplug events.
When the disk inventory changes, use the bus unit attention mechanism
to return a CHECK_CONDITION status with sense data of 0x06/0x3F/0x0E
(sense code REPORTED_LUNS_CHANGED). The first device on the bus to
execute a command successfully will report and consume the unit
attention status.
Signed-off-by: Venu Busireddy <venu.busireddy@oracle.com>
Message-Id: <20221006194946.24134-1-venu.busireddy@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
SunOS expects CD-ROM devices to have a block size of 512, and will
fail to mount or install using QEMU's default block size of 2048.
When initializing the SCSI device, allow the `physical_block_size'
block device option to override the default block size.
Signed-off-by: John Millikin <john@john-millikin.com>
Message-Id: <20220804122950.1577012-1-john@john-millikin.com>
Signed-off-by: Paolo Bonzini <pbonzini@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>
In scsi_req_parse_cdb(), if the CDB length implied by the command type
exceeds the initialized portion of the command buffer, reject the request.
Rejected requests are recorded by the `scsi_req_parse_bad` trace event.
On example of a bug detected by this check is SunOS's use of interleaved
DMA and non-DMA commands. This guest behavior currently causes QEMU to
parse uninitialized memory as a SCSI command, with unpredictable
outcomes.
With the new check in place:
* QEMU consistently creates a trace event and rejects the request.
* SunOS retries the request(s) and is able to successfully boot from
disk.
Signed-off-by: John Millikin <john@john-millikin.com>
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1127
Message-Id: <20220817053458.698416-2-john@john-millikin.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
When a SCSI command is received from the guest, the CDB length implied
by the first byte might exceed the number of bytes the guest sent. In
this case scsi_req_new() will read uninitialized data, causing
unpredictable behavior.
Adds the buf_len parameter to scsi_req_new() and plumbs it through the
call stack.
Signed-off-by: John Millikin <john@john-millikin.com>
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1127
Message-Id: <20220817053458.698416-1-john@john-millikin.com>
[Fill in correct length for adapters other than ESP. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Per investigation on the linked ticket, SunOS issues a SCSI bus reset
to the ESP as part of its boot sequence. If this ESP command doesn't
cause devices to assert sense flag UNIT ATTENTION, SunOS will consider
the CD-ROM device to be non-compliant with Common Command Set (CCS).
In this condition, the SunOS installer's early userspace doesn't set
the installation source location to sr0 and the miniroot copy fails.
Signed-off-by: John Millikin <john@john-millikin.com>
Suggested-by: Bill Paul <noisetube@gmail.com>
Buglink: https://gitlab.com/qemu-project/qemu/-/issues/1127
Message-Id: <20220817053846.699310-1-john@john-millikin.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
