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

[Song Gao]

Hi,

在 2023/5/5 下午9:24, WANG Xuerui 写道:
> 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.
'LA364' support UAL.

Thanks.
Song Gao