From 8b81253332b5a3f3c67b6462f39caef47a00dd29 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Alex=20Benn=C3=A9e?= Date: Thu, 21 Sep 2017 12:06:25 +0100 Subject: [PATCH] accel/tcg/cputlb: avoid recursive BQL (fixes #1706296) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The mmio path (see exec.c:prepare_mmio_access) already protects itself against recursive locking and it makes sense to do the same for io_readx/writex. Otherwise any helper running in the BQL context will assert when it attempts to write to device memory as in the case of the bug report. Reviewed-by: Peter Maydell Signed-off-by: Alex Bennée CC: Richard Jones CC: Paolo Bonzini CC: qemu-stable@nongnu.org Message-Id: <20170921110625.9500-1-alex.bennee@linaro.org> Signed-off-by: Richard Henderson --- accel/tcg/cputlb.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/accel/tcg/cputlb.c b/accel/tcg/cputlb.c index e72415a882b7..bcbcc4db6c23 100644 --- a/accel/tcg/cputlb.c +++ b/accel/tcg/cputlb.c @@ -765,7 +765,7 @@ static uint64_t io_readx(CPUArchState *env, CPUIOTLBEntry *iotlbentry, cpu->mem_io_vaddr = addr; - if (mr->global_locking) { + if (mr->global_locking && !qemu_mutex_iothread_locked()) { qemu_mutex_lock_iothread(); locked = true; } @@ -800,7 +800,7 @@ static void io_writex(CPUArchState *env, CPUIOTLBEntry *iotlbentry, cpu->mem_io_vaddr = addr; cpu->mem_io_pc = retaddr; - if (mr->global_locking) { + if (mr->global_locking && !qemu_mutex_iothread_locked()) { qemu_mutex_lock_iothread(); locked = true; }