motorhead/qemu
1
0
Fork 0
mirror of https://github.com/Motorhead1991/qemu.git synced 2025-08-02 23:33:54 -06:00
Code Issues Projects Releases Packages Wiki Activity Actions

async: Add an optional reentrancy guard to the BH API

Browse source 
Devices can pass their MemoryReentrancyGuard (from their DeviceState),
when creating new BHes. Then, the async API will toggle the guard
before/after calling the BH call-back. This prevents bh->mmio reentrancy
issues.

Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Message-Id: <20230427211013.2994127-3-alxndr@bu.edu>
[thuth: Fix "line over 90 characters" checkpatch.pl error]
Signed-off-by: Thomas Huth <thuth@redhat.com>
This commit is contained in:
Alexander Bulekov 2023-04-27 17:10:07 -04:00 • committed by Thomas Huth
parent a2e1753b80
commit 9c86c97f12
7 changed files with 52 additions and 8 deletions
Download patch file Download diff file Expand all files Collapse all files

7
docs/devel/multiple-iothreads.txt
View file

@ -61,6 +61,7 @@ There are several old APIs that use the main loop AioContext:
* LEGACY qemu_aio_set_event_notifier() - monitor an event notifier
* LEGACY timer_new_ms() - create a timer
* LEGACY qemu_bh_new() - create a BH
* LEGACY qemu_bh_new_guarded() - create a BH with a device re-entrancy guard
* LEGACY qemu_aio_wait() - run an event loop iteration
Since they implicitly work on the main loop they cannot be used in code that
@ -72,8 +73,14 @@ Instead, use the AioContext functions directly (see include/block/aio.h):
* aio_set_event_notifier() - monitor an event notifier
* aio_timer_new() - create a timer
* aio_bh_new() - create a BH
* aio_bh_new_guarded() - create a BH with a device re-entrancy guard
* aio_poll() - run an event loop iteration
The qemu_bh_new_guarded/aio_bh_new_guarded APIs accept a "MemReentrancyGuard"
argument, which is used to check for and prevent re-entrancy problems. For
BHs associated with devices, the reentrancy-guard is contained in the
corresponding DeviceState and named "mem_reentrancy_guard".
The AioContext can be obtained from the IOThread using
iothread_get_aio_context() or for the main loop using qemu_get_aio_context().
Code that takes an AioContext argument works both in IOThreads or the main