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| author | Alexander Bulekov <alxndr@bu.edu> | 2023-04-27 17:10:07 -0400 |
|---|---|---|
| committer | Thomas Huth <thuth@redhat.com> | 2023-04-28 11:31:07 +0200 |
| commit | 9c86c97f12c060bf7484dd931f38634e166a81f0 (patch) | |
| tree | b3e82f9abe80c39166b4880f0405b0785ba731a5 /util | |
| parent | a2e1753b8054344f32cf94f31c6399a58794a380 (diff) | |
| download | qemu-9c86c97f12c060bf7484dd931f38634e166a81f0.zip qemu-9c86c97f12c060bf7484dd931f38634e166a81f0.tar.gz qemu-9c86c97f12c060bf7484dd931f38634e166a81f0.tar.bz2 | |
async: Add an optional reentrancy guard to the BH API
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>
Diffstat (limited to 'util')
| -rw-r--r-- | util/async.c | 18 | ||||
| -rw-r--r-- | util/main-loop.c | 6 | ||||
| -rw-r--r-- | util/trace-events | 1 |
3 files changed, 22 insertions, 3 deletions
diff --git a/util/async.c b/util/async.c index 21016a1..a9b528c 100644 --- a/util/async.c +++ b/util/async.c @@ -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. */ diff --git a/util/main-loop.c b/util/main-loop.c index e180c85..7022f02 100644 --- a/util/main-loop.c +++ b/util/main-loop.c @@ -605,9 +605,11 @@ void main_loop_wait(int nonblocking) /* Functions to operate on the main QEMU AioContext. */ -QEMUBH *qemu_bh_new_full(QEMUBHFunc *cb, void *opaque, const char *name) +QEMUBH *qemu_bh_new_full(QEMUBHFunc *cb, void *opaque, const char *name, + MemReentrancyGuard *reentrancy_guard) { - return aio_bh_new_full(qemu_aio_context, cb, opaque, name); + return aio_bh_new_full(qemu_aio_context, cb, opaque, name, + reentrancy_guard); } /* diff --git a/util/trace-events b/util/trace-events index 16f78d8..3f7e766 100644 --- a/util/trace-events +++ b/util/trace-events @@ -11,6 +11,7 @@ poll_remove(void *ctx, void *node, int fd) "ctx %p node %p fd %d" # async.c aio_co_schedule(void *ctx, void *co) "ctx %p co %p" aio_co_schedule_bh_cb(void *ctx, void *co) "ctx %p co %p" +reentrant_aio(void *ctx, const char *name) "ctx %p name %s" # thread-pool.c thread_pool_submit(void *pool, void *req, void *opaque) "pool %p req %p opaque %p" |