On 8/9/25 04:58, Paolo Bonzini wrote:
cpu->exit_request do not use a load-acquire/store-release pair right now,
but this means that cpu_exit() does not store it after any flags that are
read in the slow path.
Probably everything is protected one way or the other by the BQL, because
after reading cpu->exit_request the CPU thread often goes to sleep
(by waiting on the BQL-protected cpu->halt_cond), but it's not clear.
Use load-acquire/store-release consistently.
Signed-off-by: Paolo Bonzini <[email protected]>
---
accel/kvm/kvm-all.c | 19 +++++++++----------
accel/tcg/cpu-exec.c | 7 +++++--
accel/tcg/tcg-accel-ops-rr.c | 2 +-
hw/core/cpu-common.c | 3 ++-
target/i386/nvmm/nvmm-all.c | 5 ++---
target/i386/whpx/whpx-all.c | 3 ++-
6 files changed, 21 insertions(+), 18 deletions(-)
Reviewed-by: Richard Henderson <[email protected]>
diff --git a/hw/core/cpu-common.c b/hw/core/cpu-common.c
index 39e674aca21..f189ce861c9 100644
--- a/hw/core/cpu-common.c
+++ b/hw/core/cpu-common.c
@@ -84,7 +84,8 @@ void cpu_reset_interrupt(CPUState *cpu, int mask)
void cpu_exit(CPUState *cpu)
{
- qatomic_set(&cpu->exit_request, 1);
+ /* Ensure cpu_exec will see the reason why the exit request was set. */
+ qatomic_store_release(&cpu->exit_request, 1);
While you're touching the lines, since exit_request is bool, let's use true (and elsewhere
in other patches, false).
r~
