Re: [PATCH 8/8] physmem: add missing memory barrier

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

On 3/3/23 09:19, Paolo Bonzini wrote:
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>   softmmu/physmem.c | 3 +++
>   1 file changed, 3 insertions(+)

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

r~

> 
> diff --git a/softmmu/physmem.c b/softmmu/physmem.c
> index 47143edb4f6c..a6efd8e8dd11 100644
> --- a/softmmu/physmem.c
> +++ b/softmmu/physmem.c
> @@ -2927,6 +2927,8 @@ void cpu_register_map_client(QEMUBH *bh)
>       qemu_mutex_lock(&map_client_list_lock);
>       client->bh = bh;
>       QLIST_INSERT_HEAD(&map_client_list, client, link);
> +    /* Write map_client_list before reading in_use.  */
> +    smp_mb();
>       if (!qatomic_read(&bounce.in_use)) {
>           cpu_notify_map_clients_locked();
>       }
> @@ -3116,6 +3118,7 @@ void address_space_unmap(AddressSpace *as, void *buffer, hwaddr len,
>       qemu_vfree(bounce.buffer);
>       bounce.buffer = NULL;
>       memory_region_unref(bounce.mr);
> +    /* Clear in_use before reading map_client_list.  */
>       qatomic_mb_set(&bounce.in_use, false);
>       cpu_notify_map_clients();
>   }