motorhead/qemu
1
0
Fork 0
mirror of https://github.com/Motorhead1991/qemu.git synced 2025-08-26 03:21:50 -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>
(cherry picked from commit 9c86c97f12)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
This commit is contained in:
Alexander Bulekov 2023-04-27 17:10:07 -04:00 • committed by Michael Tokarev
parent a08c78dda7
commit 932cf49f06
7 changed files with 52 additions and 8 deletions
Download patch file Download diff file Expand all files Collapse all files

18
util/async.c
View file

@ -65,6 +65,7 @@ struct QEMUBH {
void *opaque;
QSLIST_ENTRY(QEMUBH) next;
unsigned flags;
MemReentrancyGuard *reentrancy_guard;
};
/* Called concurrently from any thread */
@ -137,7 +138,7 @@ void aio_bh_schedule_oneshot_full(AioContext *ctx, QEMUBHFunc *cb,
}
QEMUBH *aio_bh_new_full(AioContext *ctx, QEMUBHFunc *cb, void *opaque,
const char *name)
const char *name, MemReentrancyGuard *reentrancy_guard)
{
QEMUBH *bh;
bh = g_new(QEMUBH, 1);
@ -146,13 +147,28 @@ QEMUBH *aio_bh_new_full(AioContext *ctx, QEMUBHFunc *cb, void *opaque,
.cb = cb,
.opaque = opaque,
.name = name,
.reentrancy_guard = reentrancy_guard,
};
return bh;
}
void aio_bh_call(QEMUBH *bh)
{
bool last_engaged_in_io = false;
if (bh->reentrancy_guard) {
last_engaged_in_io = bh->reentrancy_guard->engaged_in_io;
if (bh->reentrancy_guard->engaged_in_io) {
trace_reentrant_aio(bh->ctx, bh->name);
}
bh->reentrancy_guard->engaged_in_io = true;
}
bh->cb(bh->opaque);
if (bh->reentrancy_guard) {
bh->reentrancy_guard->engaged_in_io = last_engaged_in_io;
}
}
/* Multiple occurrences of aio_bh_poll cannot be called concurrently. */