Re: [PATCH v2 10/13] accel/tcg: Remove NULL check in tcg_flush_jmp_cache()

[Ilya Leoshkevich]

On Mon, Apr 29, 2024 at 11:30:47PM +0200, Philippe Mathieu-Daudé wrote:
> I /think/ this check added in commit 4e4fa6c12d ("accel/tcg:
> Complete cpu initialization before registration") is now
> unnecessary, but I don't have the WASM reproducer mentioned
> in:
> https://lore.kernel.org/qemu-devel/20221027141856.w5umjgklawgu7pqv@heavy/
> to confirm. Ilya, do you mind testing? If so, we could
> squash this with the previous patch.
> 
> Cc: Ilya Leoshkevich 
> Signed-off-by: Philippe Mathieu-Daudé 
> ---
>  accel/tcg/translate-all.c | 8 +---
>  1 file changed, 1 insertion(+), 7 deletions(-)
> 
> diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c
> index ca1e193633..9b02f21b23 100644
> --- a/accel/tcg/translate-all.c
> +++ b/accel/tcg/translate-all.c
> @@ -652,14 +652,8 @@ void cpu_io_recompile(CPUState *cpu, uintptr_t retaddr)
>   */
>  void tcg_flush_jmp_cache(CPUState *cpu)
>  {
> -CPUJumpCache *jc;
> +CPUJumpCache *jc = >accel->tb_jmp_cache;
>  
> -/* During early initialization, the cache may not yet be allocated. */
> -if (unlikely(cpu->accel == NULL)) {
> -return;
> -}
> -
> -jc = >accel->tb_jmp_cache;
>  for (int i = 0; i < TB_JMP_CACHE_SIZE; i++) {
>  qatomic_set(>array[i].tb, NULL);
>  }
> -- 
> 2.41.0
> 

Sure, I'll have a look tomorrow.

[PATCH v2 10/13] accel/tcg: Remove NULL check in tcg_flush_jmp_cache()

[Philippe Mathieu-Daudé]

I /think/ this check added in commit 4e4fa6c12d ("accel/tcg:
Complete cpu initialization before registration") is now
unnecessary, but I don't have the WASM reproducer mentioned
in:
https://lore.kernel.org/qemu-devel/20221027141856.w5umjgklawgu7pqv@heavy/
to confirm. Ilya, do you mind testing? If so, we could
squash this with the previous patch.

Cc: Ilya Leoshkevich 
Signed-off-by: Philippe Mathieu-Daudé 
---
 accel/tcg/translate-all.c | 8 +---
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c
index ca1e193633..9b02f21b23 100644
--- a/accel/tcg/translate-all.c
+++ b/accel/tcg/translate-all.c
@@ -652,14 +652,8 @@ void cpu_io_recompile(CPUState *cpu, uintptr_t retaddr)
  */
 void tcg_flush_jmp_cache(CPUState *cpu)
 {
-CPUJumpCache *jc;
+CPUJumpCache *jc = >accel->tb_jmp_cache;
 
-/* During early initialization, the cache may not yet be allocated. */
-if (unlikely(cpu->accel == NULL)) {
-return;
-}
-
-jc = >accel->tb_jmp_cache;
 for (int i = 0; i < TB_JMP_CACHE_SIZE; i++) {
 qatomic_set(>array[i].tb, NULL);
 }
-- 
2.41.0