diff options
| author | Nicholas Piggin <npiggin@gmail.com> | 2023-08-29 11:06:58 +1000 |
|---|---|---|
| committer | Michael Tokarev <mjt@tls.msk.ru> | 2023-09-27 21:39:52 +0300 |
| commit | e6fdfb8433743bc882d11728b6b9e3d03f8ccdd2 (patch) | |
| tree | f6be612b6a050c3335e40bf718c1bc736ba007eb | |
| parent | c8d2fc2177cfa020bc37937e46fbfe8d0bc6043f (diff) | |
accel/tcg: mttcg remove false-negative halted assertion
mttcg asserts that an execution ending with EXCP_HALTED must have
cpu->halted. However between the event or instruction that sets
cpu->halted and requests exit and the assertion here, an
asynchronous event could clear cpu->halted.
This leads to crashes running AIX on ppc/pseries because it uses
H_CEDE/H_PROD hcalls, where H_CEDE sets self->halted = 1 and
H_PROD sets other cpu->halted = 0 and kicks it.
H_PROD could be turned into an interrupt to wake, but several other
places in ppc, sparc, and semihosting follow what looks like a similar
pattern setting halted = 0 directly. So remove this assertion.
Reported-by: Ivan Warren <ivan@vmfacility.fr>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Message-Id: <20230829010658.8252-1-npiggin@gmail.com>
[rth: Keep the case label and adjust the comment.]
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
(cherry picked from commit 0e5903436de712844b0e6cdd862b499c767e09e9)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
| -rw-r--r-- | accel/tcg/tcg-accel-ops-mttcg.c | 9 |
1 files changed, 2 insertions, 7 deletions
diff --git a/accel/tcg/tcg-accel-ops-mttcg.c b/accel/tcg/tcg-accel-ops-mttcg.c index d50239e0e2..3a021624f4 100644 --- a/accel/tcg/tcg-accel-ops-mttcg.c +++ b/accel/tcg/tcg-accel-ops-mttcg.c @@ -100,14 +100,9 @@ static void *mttcg_cpu_thread_fn(void *arg) break; case EXCP_HALTED: /* - * during start-up the vCPU is reset and the thread is - * kicked several times. If we don't ensure we go back - * to sleep in the halted state we won't cleanly - * start-up when the vCPU is enabled. - * - * cpu->halted should ensure we sleep in wait_io_event + * Usually cpu->halted is set, but may have already been + * reset by another thread by the time we arrive here. */ - g_assert(cpu->halted); break; case EXCP_ATOMIC: qemu_mutex_unlock_iothread(); |