Re: [PATCH v4 36/57] tcg/loongarch64: Assert the host supports unaligned accesses

[WANG Xuerui]

Hi,

On 2023/5/3 15:06, Richard Henderson wrote:
> This should be true of all server class loongarch64.
And desktop-class (i.e. all Loongson-3 series).
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>   tcg/loongarch64/tcg-target.c.inc | 6 ++++++
>   1 file changed, 6 insertions(+)
>
> diff --git a/tcg/loongarch64/tcg-target.c.inc b/tcg/loongarch64/tcg-target.c.inc
> index e651ec5c71..ccc13ffdb4 100644
> --- a/tcg/loongarch64/tcg-target.c.inc
> +++ b/tcg/loongarch64/tcg-target.c.inc
> @@ -30,6 +30,7 @@
>    */
>   
>   #include "../tcg-ldst.c.inc"
> +#include <asm/hwcap.h>
>   
>   #ifdef CONFIG_DEBUG_TCG
>   static const char * const tcg_target_reg_names[TCG_TARGET_NB_REGS] = {
> @@ -1674,6 +1675,11 @@ static void tcg_target_qemu_prologue(TCGContext *s)
>   
>   static void tcg_target_init(TCGContext *s)
>   {
> +    unsigned long hwcap = qemu_getauxval(AT_HWCAP);
> +
> +    /* All server class loongarch have UAL; only embedded do not. */
> +    assert(hwcap & HWCAP_LOONGARCH_UAL);
> +
It is a bit worrying that a future SoC (the octa-core Loongson 2K3000) 
might get used for light desktop use cases (e.g. laptops) where QEMU is 
arguably relevant, but it's currently unclear whether its LA364 
micro-architecture will have UAL. The Loongson folks may have more to share.
>       tcg_target_available_regs[TCG_TYPE_I32] = ALL_GENERAL_REGS;
>       tcg_target_available_regs[TCG_TYPE_I64] = ALL_GENERAL_REGS;
>