Re: [PATCH 3/4] accel/hvf: Make async_safe_run_on_cpu() safe

[Richard Henderson <richard.henderson@linaro.org>]

On 9/24/25 19:55, Philippe Mathieu-Daudé wrote:
> Wrap hv_vcpu_run() calls with cpu_exec_start/end() in order to
> have the main loop perform more exclusive sections while all
> vCPUs are quiescent.
> 
> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> ---
> Could be related to the dubious thread_kicked access and pselect() in
> hvf_wait_for_ipi() (commit 219c101fa7f "arm/hvf: Add a WFI handler").
> 
> Cc: Peter Collingbourne <pcc@google.com>
> Cc: Alexander Graf <agraf@csgraf.de>
> Cc: Roman Bolshakov <r.bolshakov@yadro.com>
> Cc: Sergio Lopez <slp@redhat.com>
> ---
>   target/arm/hvf/hvf.c  | 2 ++
>   target/i386/hvf/hvf.c | 2 ++
>   2 files changed, 4 insertions(+)

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

r~

> 
> diff --git a/target/arm/hvf/hvf.c b/target/arm/hvf/hvf.c
> index b77db99079e..377eb4bbc6b 100644
> --- a/target/arm/hvf/hvf.c
> +++ b/target/arm/hvf/hvf.c
> @@ -1927,7 +1927,9 @@ int hvf_vcpu_exec(CPUState *cpu)
>       flush_cpu_state(cpu);
>   
>       bql_unlock();
> +    cpu_exec_start(cpu);
>       r = hv_vcpu_run(cpu->accel->fd);
> +    cpu_exec_end(cpu);
>       bql_lock();
>       switch (r) {
>       case HV_SUCCESS:
> diff --git a/target/i386/hvf/hvf.c b/target/i386/hvf/hvf.c
> index 8445cadecec..913ad47f3d8 100644
> --- a/target/i386/hvf/hvf.c
> +++ b/target/i386/hvf/hvf.c
> @@ -749,8 +749,10 @@ int hvf_vcpu_exec(CPUState *cpu)
>               return EXCP_HLT;
>           }
>   
> +        cpu_exec_start(cpu);
>           hv_return_t r = hv_vcpu_run_until(cpu->accel->fd, HV_DEADLINE_FOREVER);
>           assert_hvf_ok(r);
> +        cpu_exec_end(cpu);
>   
>           /* handle VMEXIT */
>           uint64_t exit_reason = rvmcs(cpu->accel->fd, VMCS_EXIT_REASON);