This patch adds edid support to the qemu stdvga.  It is turned off by
default and can be enabled with the new edid property.  The patch also
adds xres and yres properties to specify the video mode you want the
guest use.  Works only with edid enabled and updated guest driver.

The mmio bar of the stdvga has some unused address space at the start.
It was reserved just in case it'll be needed for virtio, but it turned
out to not be needed for that.  So let's use that region to place the
EDID data block there.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Message-id: 20180925075646.25114-6-kraxel@redhat.com

Add a define for edid monitor properties.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Message-id: 20180925075646.25114-5-kraxel@redhat.com

Create a io region for an EDID data block.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Reviewed-by: NPhilippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20180925075646.25114-4-kraxel@redhat.com

Helper function to figure the size of a edid blob, by checking how many
extensions are present.  Both the base edid blob and the extensions are
128 bytes in size.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Message-id: 20180925075646.25114-3-kraxel@redhat.com

EDID is a metadata format to describe monitors.  On physical hardware
the monitor has an eeprom with that data block which can be read over
i2c bus.

On a linux system you can usually find the EDID data block in
/sys/class/drm/$card/$connector/edid.  xorg ships a edid-decode utility
which you can use to turn the blob into readable form.

I think it would be a good idea to use EDID for virtual displays too.
Needs changes in both qemu and guest kms drivers.  This patch is the
first step, it adds an generator for EDID blobs to qemu.  Comes with a
qemu-edid test tool included.

With EDID we can pass more information to the guest.  Names and serial
numbers, so the guests display configuration has no boring "Unknown
Monitor".  List of video modes.  Display resolution, pretty important
in case we want add HiDPI support some day.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Message-id: 20180925075646.25114-2-kraxel@redhat.com

Block layer patches:
- Drain fixes
- node-name parameters for block-commit
- Refactor block jobs to use transactional callbacks for exiting

# gpg: Signature made Tue 25 Sep 2018 16:12:44 BST
# gpg:                using RSA key F407DB0061D5CF40
# gpg: Good signature from "Max Reitz <mreitz@redhat.com>"
# Primary key fingerprint: 91BE B60A 30DB 3E88 57D1  1829 F407 DB00 61D5 CF40

* remotes/xanclic/tags/pull-block-2018-09-25: (42 commits)
  test-bdrv-drain: Test draining job source child and parent
  block: Use a single global AioWait
  test-bdrv-drain: Fix outdated comments
  test-bdrv-drain: AIO_WAIT_WHILE() in job .commit/.abort
  job: Avoid deadlocks in job_completed_txn_abort()
  test-bdrv-drain: Test nested poll in bdrv_drain_poll_top_level()
  block: Remove aio_poll() in bdrv_drain_poll variants
  blockjob: Lie better in child_job_drained_poll()
  block-backend: Decrease in_flight only after callback
  block-backend: Fix potential double blk_delete()
  block-backend: Add .drained_poll callback
  block: Add missing locking in bdrv_co_drain_bh_cb()
  test-bdrv-drain: Test AIO_WAIT_WHILE() in completion callback
  job: Use AIO_WAIT_WHILE() in job_finish_sync()
  test-blockjob: Acquire AioContext around job_cancel_sync()
  test-bdrv-drain: Drain with block jobs in an I/O thread
  aio-wait: Increase num_waiters even in home thread
  blockjob: Wake up BDS when job becomes idle
  job: Fix missing locking due to mismerge
  job: Fix nested aio_poll() hanging in job_txn_apply
  ...
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

HMP pull 2018-09-25

# gpg: Signature made Tue 25 Sep 2018 15:11:09 BST
# gpg:                using RSA key 0516331EBC5BFDE7
# gpg: Good signature from "Dr. David Alan Gilbert (RH2) <dgilbert@redhat.com>"
# Primary key fingerprint: 45F5 C71B 4A0C B7FB 977A  9FA9 0516 331E BC5B FDE7

* remotes/dgilbert/tags/pull-hmp-20180925:
  qmp, hmp: add PCI subsystem id and vendor id to PCI info
  hmp: fix migrate status timer leak
  monitor: print message when using 'help' with an unknown command
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

target-arm queue:
 * target/arm: Fix cpu_get_tb_cpu_state() for non-SVE CPUs
 * hw/arm/exynos4210: fix Exynos4210 UART support
 * hw/arm/virt-acpi-build: Add a check for memory-less NUMA nodes
 * arm: Add BBC micro:bit machine
 * aspeed/i2c: Fix interrupt handling bugs
 * hw/arm/smmu-common: Fix the name of the iommu memory regions
 * hw/arm/smmuv3: fix eventq recording and IRQ triggerring
 * hw/intc/arm_gic: Document QEMU interface
 * hw/intc/arm_gic: Drop GIC_BASE_IRQ macro
 * hw/net/pcnet-pci: Convert away from old_mmio accessors
 * hw/timer/cmsdk-apb-dualtimer: Add missing 'break' statements
 * aspeed/timer: fix compile breakage with clang 3.4.2
 * hw/arm/aspeed: change the FMC flash model of the AST2500 evb
 * hw/arm/aspeed: Minor code cleanups
 * target/arm: Start AArch32 CPUs with EL2 but not EL3 in Hyp mode

# gpg: Signature made Tue 25 Sep 2018 15:23:11 BST
# gpg:                using RSA key 3C2525ED14360CDE
# gpg: Good signature from "Peter Maydell <peter.maydell@linaro.org>"
# gpg:                 aka "Peter Maydell <pmaydell@gmail.com>"
# gpg:                 aka "Peter Maydell <pmaydell@chiark.greenend.org.uk>"
# Primary key fingerprint: E1A5 C593 CD41 9DE2 8E83  15CF 3C25 25ED 1436 0CDE

* remotes/pmaydell/tags/pull-target-arm-20180925-1: (21 commits)
  target/arm: Start AArch32 CPUs with EL2 but not EL3 in Hyp mode
  aspeed/smc: fix some alignment issues
  hw/arm/aspeed: Add an Aspeed machine class
  hw/arm/aspeed: change the FMC flash model of the AST2500 evb
  aspeed/timer: fix compile breakage with clang 3.4.2
  hw/timer/cmsdk-apb-dualtimer: Add missing 'break' statements
  hw/net/pcnet-pci: Unify pcnet_ioport_read/write and pcnet_mmio_read/write
  hw/net/pcnet-pci: Convert away from old_mmio accessors
  hw/intc/arm_gic: Drop GIC_BASE_IRQ macro
  hw/intc/arm_gic: Document QEMU interface
  hw/arm/smmuv3: fix eventq recording and IRQ triggerring
  hw/arm/smmu-common: Fix the name of the iommu memory regions
  aspeed/i2c: Fix receive done interrupt handling
  aspeed/i2c: Handle receive command in separate function
  aspeed/i2c: interrupts should be cleared by software only
  arm: Add BBC micro:bit machine
  arm: Add Nordic Semiconductor nRF51 SoC
  MAINTAINERS: Add NRF51 entry
  hw/arm/virt-acpi-build: Add a check for memory-less NUMA nodes
  hw/arm/exynos4210: fix Exynos4210 UART support
  ...
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

The ARMv8 architecture defines that an AArch32 CPU starts
in SVC mode, unless EL2 is the highest available EL, in
which case it starts in Hyp mode. (In ARMv7 a CPU with EL2
but not EL3 was not a valid configuration, but we don't
specifically reject this if the user asks for one.)
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
Reviewed-by: NPhilippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20180823135047.16525-1-peter.maydell@linaro.org

Signed-off-by: NCédric Le Goater <clg@kaod.org>
Reviewed-by: NPhilippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20180921161939.822-6-clg@kaod.org
Reviewed-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

The code looks better, it removes duplicated lines and it will ease
the introduction of common properties for the Aspeed machines.
Signed-off-by: NCédric Le Goater <clg@kaod.org>
Reviewed-by: NPhilippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20180921161939.822-4-clg@kaod.org
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

The AST2500 evb is shipped with a W25Q256 which has a non volatile bit
to make the chip operate in 4 Byte address mode at power up. This
should be an interesting feature to model as it will exercise a bit
more the SMC controllers and MMIO execution at boot time.
Signed-off-by: NCédric Le Goater <clg@kaod.org>
Message-id: 20180921161939.822-3-clg@kaod.org
Reviewed-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

In file included from /home/thuth/devel/qemu/hw/timer/aspeed_timer.c:16:
/home/thuth/devel/qemu/include/hw/misc/aspeed_scu.h:37:3: error:
redefinition of typedef 'AspeedSCUState' is a C11 feature
      [-Werror,-Wtypedef-redefinition]
} AspeedSCUState;
  ^
/home/thuth/devel/qemu/include/hw/timer/aspeed_timer.h:27:31: note:
previous definition is here
typedef struct AspeedSCUState AspeedSCUState;
Reported-by: NThomas Huth <thuth@redhat.com>
Signed-off-by: NCédric Le Goater <clg@kaod.org>
Reviewed-by: NPhilippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20180921161939.822-2-clg@kaod.org
Reviewed-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

Add 'break' statements missing from a switch in the APB dual-timer
write function. Spotted by Coverity as CID 1395626 and 1395633.
Reported-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
Reviewed-by: NPhilippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20180924123122.14549-1-peter.maydell@linaro.org

The only difference between our implementation of the pcnet ioport
accessors and the mmio accessors is that the former check BCR_DWIO to
see what access widths are permitted for addresses in the aprom range
(0x0..0xf). In fact our failure to do this in the mmio accessors
is a bug (one which was fixed for the ioport accessors in
commit 7ba79741 in 2011).

The data sheet for the Am79C970A does not describe the DWIO
bit as only applying for I/O space mapped I/O resources and
not memory mapped I/O resources, and our MMIO accessors already
honour DWIO for accesses in the 0x10..0x1f range (since the
pcnet_ioport_{read,write}{w,l} functions check it).

The data sheet for the later but compatible Am79C976 is clearer:
it states specifically "DWIO mode applies to both I/O- and
memory-mapped acceses." This seems to be reasonable evidence
in favour of interpretating the Am79C970A spec as being the same.

(NB: Linux's pcnet driver only supports I/O accesses, so the
MMIO access part of this device is probably untested anyway.)
Reviewed-by: NRichard Henderson <richard.henderson@linaro.org>
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

Convert the pcnet-pci device away from using the old_mmio
MemoryRegionOps accessor functions.

This commit is a no-behaviour-change API conversion.
(Since PCNET_PNPMMIO_SIZE is 0x20, the old "addr & 0x10"
check and the new "addr < 0x10" check are exact opposites;
the new code is phrased to be parallel with the
pcnet_io_read/write functions.)

I have left a TODO comment marker because the similarity
between the MMIO and IO accessor behaviour is suspicious
and they could be combined, but this will be left to a
different patch.
Reviewed-by: NRichard Henderson <richard.henderson@linaro.org>
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

The GIC_BASE_IRQ macro is a leftover from when we shared code
between the GICv2 and the v7M NVIC. Since the NVIC is now
split off, GIC_BASE_IRQ is always 0, and we can just delete it.
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
Reviewed-by: NPhilippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: NLuc Michel <luc.michel@greensocs.com>
Message-id: 20180824161819.11085-1-peter.maydell@linaro.org

The GICv2's QEMU interface (sysbus MMIO regions, IRQs,
etc) is now quite complicated with the addition of the
virtualization extensions. Add a comment in the header
file which documents it.
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
Reviewed-by: NLuc Michel <luc.michel@greensocs.com>
Message-id: 20180823103818.31189-1-peter.maydell@linaro.org

The event queue management is broken today. Event records
are not properly written as EVT_SET_* macro was not updating
the actual event record. Also the event queue interrupt
is not correctly triggered.

Fixes: bb981004 ("hw/arm/smmuv3: Event queue recording helper")
Signed-off-by: NEric Auger <eric.auger@redhat.com>
Message-id: 20180921070138.10114-3-eric.auger@redhat.com
Reviewed-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

Block layer patches:

- Fix some jobs/drain/aio_poll related hangs
- commit: Add top-node/base-node options
- linux-aio: Fix locking for qemu_laio_process_completions()
- Fix use after free error in bdrv_open_inherit

# gpg: Signature made Tue Sep 25 15:54:01 2018 CEST
# gpg:                using RSA key 7F09B272C88F2FD6
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>"
# Primary key fingerprint: DC3D EB15 9A9A F95D 3D74  56FE 7F09 B272 C88F 2FD6

* kevin/tags/for-upstream: (26 commits)
  test-bdrv-drain: Test draining job source child and parent
  block: Use a single global AioWait
  test-bdrv-drain: Fix outdated comments
  test-bdrv-drain: AIO_WAIT_WHILE() in job .commit/.abort
  job: Avoid deadlocks in job_completed_txn_abort()
  test-bdrv-drain: Test nested poll in bdrv_drain_poll_top_level()
  block: Remove aio_poll() in bdrv_drain_poll variants
  blockjob: Lie better in child_job_drained_poll()
  block-backend: Decrease in_flight only after callback
  block-backend: Fix potential double blk_delete()
  block-backend: Add .drained_poll callback
  block: Add missing locking in bdrv_co_drain_bh_cb()
  test-bdrv-drain: Test AIO_WAIT_WHILE() in completion callback
  job: Use AIO_WAIT_WHILE() in job_finish_sync()
  test-blockjob: Acquire AioContext around job_cancel_sync()
  test-bdrv-drain: Drain with block jobs in an I/O thread
  aio-wait: Increase num_waiters even in home thread
  blockjob: Wake up BDS when job becomes idle
  job: Fix missing locking due to mismerge
  job: Fix nested aio_poll() hanging in job_txn_apply
  ...
Signed-off-by: NMax Reitz <mreitz@redhat.com>

For the block job drain test, don't only test draining the source and
the target node, but create a backing chain for the source
(source_backing <- source <- source_overlay) and test draining each of
the nodes in it.

When using iothreads, the source node (and therefore the job) is in a
different AioContext than the drain, which happens from the main
thread. This way, the main thread waits in AIO_WAIT_WHILE() for the
iothread to make process and aio_wait_kick() is required to notify it.
The test validates that calling bdrv_wakeup() for a child or a parent
node will actually notify AIO_WAIT_WHILE() instead of letting it hang.

Increase the sleep time a bit (to 1 ms) because the test case is racy
and with the shorter sleep, it didn't reproduce the bug it is supposed
to test for me under 'rr record -n'.

This was because bdrv_drain_invoke_entry() (in the main thread) was only
called after the job had already reached the pause point, so we got a
bdrv_dec_in_flight() from the main thread and the additional
aio_wait_kick() when the job becomes idle (that we really wanted to test
here) wasn't even necessary any more to make progress.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NMax Reitz <mreitz@redhat.com>

When draining a block node, we recurse to its parent and for subtree
drains also to its children. A single AIO_WAIT_WHILE() is then used to
wait for bdrv_drain_poll() to become true, which depends on all of the
nodes we recursed to. However, if the respective child or parent becomes
quiescent and calls bdrv_wakeup(), only the AioWait of the child/parent
is checked, while AIO_WAIT_WHILE() depends on the AioWait of the
original node.

Fix this by using a single AioWait for all callers of AIO_WAIT_WHILE().

This may mean that the draining thread gets a few more unnecessary
wakeups because an unrelated operation got completed, but we already
wake it up when something _could_ have changed rather than only if it
has certainly changed.

Apart from that, drain is a slow path anyway. In theory it would be
possible to use wakeups more selectively and still correctly, but the
gains are likely not worth the additional complexity. In fact, this
patch is a nice simplification for some places in the code.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NMax Reitz <mreitz@redhat.com>

Commit 89bd0305 changed the test case from using job_sleep_ns() to
using qemu_co_sleep_ns() instead. Also, block_job_sleep_ns() became
job_sleep_ns() in commit 5d43e86e.

In both cases, some comments in the test case were not updated. Do that
now.
Reported-by: NMax Reitz <mreitz@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

This adds tests for calling AIO_WAIT_WHILE() in the .commit and .abort
callbacks. Both reasons why .abort could be called for a single job are
tested: Either .run or .prepare could return an error.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NMax Reitz <mreitz@redhat.com>

Amongst others, job_finalize_single() calls the .prepare/.commit/.abort
callbacks of the individual job driver. Recently, their use was adapted
for all block jobs so that they involve code calling AIO_WAIT_WHILE()
now. Such code must be called under the AioContext lock for the
respective job, but without holding any other AioContext lock.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NMax Reitz <mreitz@redhat.com>

This is a regression test for a deadlock that could occur in callbacks
called from the aio_poll() in bdrv_drain_poll_top_level(). The
AioContext lock wasn't released and therefore would be taken a second
time in the callback. This would cause a possible AIO_WAIT_WHILE() in
the callback to hang.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NFam Zheng <famz@redhat.com>

bdrv_drain_poll_top_level() was buggy because it didn't release the
AioContext lock of the node to be drained before calling aio_poll().
This way, callbacks called by aio_poll() would possibly take the lock a
second time and run into a deadlock with a nested AIO_WAIT_WHILE() call.

However, it turns out that the aio_poll() call isn't actually needed any
more. It was introduced in commit 91af091f, which is effectively
reverted by this patch. The cases it was supposed to fix are now covered
by bdrv_drain_poll(), which waits for block jobs to reach a quiescent
state.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NFam Zheng <famz@redhat.com>
Reviewed-by: NMax Reitz <mreitz@redhat.com>

Block jobs claim in .drained_poll() that they are in a quiescent state
as soon as job->deferred_to_main_loop is true. This is obviously wrong,
they still have a completion BH to run. We only get away with this
because commit 91af091f added an unconditional aio_poll(false) to the
drain functions, but this is bypassing the regular drain mechanisms.

However, just removing this and telling that the job is still active
doesn't work either: The completion callbacks themselves call drain
functions (directly, or indirectly with bdrv_reopen), so they would
deadlock then.

As a better lie, tell that the job is active as long as the BH is
pending, but falsely call it quiescent from the point in the BH when the
completion callback is called. At this point, nested drain calls won't
deadlock because they ignore the job, and outer drains will wait for the
job to really reach a quiescent state because the callback is already
running.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NMax Reitz <mreitz@redhat.com>

Request callbacks can do pretty much anything, including operations that
will yield from the coroutine (such as draining the backend). In that
case, a decreased in_flight would be visible to other code and could
lead to a drain completing while the callback hasn't actually completed
yet.

Note that reordering these operations forbids calling drain directly
inside an AIO callback. As Paolo explains, indirectly calling it is
okay:

- Calling it through a coroutine is okay, because then
  bdrv_drained_begin() goes through bdrv_co_yield_to_drain() and you
  have in_flight=2 when bdrv_co_yield_to_drain() yields, then soon
  in_flight=1 when the aio_co_wake() in the AIO callback completes, then
  in_flight=0 after the bottom half starts.

- Calling it through a bottom half would be okay too, as long as the AIO
  callback remembers to do inc_in_flight/dec_in_flight just like
  bdrv_co_yield_to_drain() and bdrv_co_drain_bh_cb() do

A few more important cases that come to mind:

- A coroutine that yields because of I/O is okay, with a sequence
  similar to bdrv_co_yield_to_drain().

- A coroutine that yields with no I/O pending will correctly decrease
  in_flight to zero before yielding.

- Calling more AIO from the callback won't overflow the counter just
  because of mutual recursion, because AIO functions always yield at
  least once before invoking the callback.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NFam Zheng <famz@redhat.com>
Reviewed-by: NMax Reitz <mreitz@redhat.com>
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>

blk_unref() first decreases the refcount of the BlockBackend and calls
blk_delete() if the refcount reaches zero. Requests can still be in
flight at this point, they are only drained during blk_delete():

At this point, arbitrary callbacks can run. If any callback takes a
temporary BlockBackend reference, it will first increase the refcount to
1 and then decrease it to 0 again, triggering another blk_delete(). This
will cause a use-after-free crash in the outer blk_delete().

Fix it by draining the BlockBackend before decreasing to refcount to 0.
Assert in blk_ref() that it never takes the first refcount (which would
mean that the BlockBackend is already being deleted).
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NFam Zheng <famz@redhat.com>
Reviewed-by: NMax Reitz <mreitz@redhat.com>

A bdrv_drain operation must ensure that all parents are quiesced, this
includes BlockBackends. Otherwise, callbacks called by requests that are
completed on the BDS layer, but not quite yet on the BlockBackend layer
could still create new requests.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NFam Zheng <famz@redhat.com>
Reviewed-by: NMax Reitz <mreitz@redhat.com>

bdrv_do_drained_begin/end() assume that they are called with the
AioContext lock of bs held. If we call drain functions from a coroutine
with the AioContext lock held, we yield and schedule a BH to move out of
coroutine context. This means that the lock for the home context of the
coroutine is released and must be re-acquired in the bottom half.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NMax Reitz <mreitz@redhat.com>

This is a regression test for a deadlock that occurred in block job
completion callbacks (via job_defer_to_main_loop) because the AioContext
lock was taken twice: once in job_finish_sync() and then again in
job_defer_to_main_loop_bh(). This would cause AIO_WAIT_WHILE() to hang.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NFam Zheng <famz@redhat.com>

job_finish_sync() needs to release the AioContext lock of the job before
calling aio_poll(). Otherwise, callbacks called by aio_poll() would
possibly take the lock a second time and run into a deadlock with a
nested AIO_WAIT_WHILE() call.

Also, job_drain() without aio_poll() isn't necessarily enough to make
progress on a job, it could depend on bottom halves to be executed.

Combine both open-coded while loops into a single AIO_WAIT_WHILE() call
that solves both of these problems.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NFam Zheng <famz@redhat.com>
Reviewed-by: NMax Reitz <mreitz@redhat.com>

All callers in QEMU proper hold the AioContext lock when calling
job_finish_sync(). test-blockjob should do the same when it calls the
function indirectly through job_cancel_sync().
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NFam Zheng <famz@redhat.com>

This extends the existing drain test with a block job to include
variants where the block job runs in a different AioContext.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NFam Zheng <famz@redhat.com>

Even if AIO_WAIT_WHILE() is called in the home context of the
AioContext, we still want to allow the condition to change depending on
other threads as long as they kick the AioWait. Specfically block jobs
can be running in an I/O thread and should then be able to kick a drain
in the main loop context.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NFam Zheng <famz@redhat.com>

In the context of draining a BDS, the .drained_poll callback of block
jobs is called. If this returns true (i.e. there is still some activity
pending), the drain operation may call aio_poll() with blocking=true to
wait for completion.

As soon as the pending activity is completed and the job finally arrives
in a quiescent state (i.e. its coroutine either yields with busy=false
or terminates), the block job must notify the aio_poll() loop to wake
up, otherwise we get a deadlock if both are running in different
threads.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NFam Zheng <famz@redhat.com>
Reviewed-by: NMax Reitz <mreitz@redhat.com>

job_completed() had a problem with double locking that was recently
fixed independently by two different commits:

"job: Fix nested aio_poll() hanging in job_txn_apply"
"jobs: add exit shim"

One fix removed the first aio_context_acquire(), the other fix removed
the other one. Now we have a bug again and the code is run without any
locking.

Add it back in one of the places.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NMax Reitz <mreitz@redhat.com>
Reviewed-by: NJohn Snow <jsnow@redhat.com>

All callers have acquired ctx already. Doing that again results in
aio_poll() hang. This fixes the problem that a BDRV_POLL_WHILE() in the
callback cannot make progress because ctx is recursively locked, for
example, when drive-backup finishes.

There are two callers of job_finalize():

    fam@lemon:~/work/qemu [master]$ git grep -w -A1 '^\s*job_finalize'
    blockdev.c:    job_finalize(&job->job, errp);
    blockdev.c-    aio_context_release(aio_context);
    --
    job-qmp.c:    job_finalize(job, errp);
    job-qmp.c-    aio_context_release(aio_context);
    --
    tests/test-blockjob.c:    job_finalize(&job->job, &error_abort);
    tests/test-blockjob.c-    assert(job->job.status == JOB_STATUS_CONCLUDED);

Ignoring the test, it's easy to see both callers to job_finalize (and
job_do_finalize) have acquired the context.

Cc: qemu-stable@nongnu.org
Reported-by: NGu Nini <ngu@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NFam Zheng <famz@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>