Re: [PATCH] i386/cpu_dump: support AVX512 ZMM regs dump

[Richard Henderson]

On 3/23/21 1:00 AM, Robert Hoo wrote:
> On Mon, 2021-03-22 at 15:06 -0600, Richard Henderson wrote:
> > On 3/22/21 4:59 AM, Robert Hoo wrote:
> > > Since commit fa4518741e (target-i386: Rename struct XMMReg to
> > > ZMMReg),
> > > CPUX86State.xmm_regs[] has already been extended to 512bit to
> > > support
> > > AVX512.
> > > Also, other qemu level supports for AVX512 registers are there for
> > > years.
> > > But in x86_cpu_dump_state(), still only dump XMM registers.
> > > This patch is just to complement this part, let it dump ZMM of
> > > 512bits.
> >
> > I think you should examine the state of the cpu to determine what of
> > SSE, AVX
> > or AVX512 is currently enabled, then dump that.
>
> Thanks Richard for review.
>
> Uh, looks like the existing code doesn't have this logic yet.
> OK, I'm to add this logic.

Correct.


> > > -        if (env->hflags & HF_CS64_MASK)
> > > -            nb = 16;
> > > -        else
> > > -            nb = 8;
> > > -        for(i=0;i<nb;i++) {
> > > -            qemu_fprintf(f, "XMM%02d=%08x%08x%08x%08x",
> > > +
> > > +        nb = sizeof(env->xmm_regs) / sizeof(env->xmm_regs[0]);
> >
> > E.g., you're dumping all of the registers in 32-bit mode, which is
> > restricted
> > to 8 registers, not 32.
>
> In typedef struct CPUX86State {
> ...
> ZMMReg xmm_regs[CPU_NB_REGS == 8 ? 8 : 32];
> ...
> }
>
> where in cpu.h
>
> #define CPU_NB_REGS64 16
> #define CPU_NB_REGS32 8
>
> #ifdef TARGET_X86_64
> #define CPU_NB_REGS CPU_NB_REGS64
> #else
> #define CPU_NB_REGS CPU_NB_REGS32
> #endif
>
> so the register number is 8 in 32-bit mode and 32 in 64-bit mode.

The array size is the maximum.  But of course a 64-bit cpu can be put into 
32-bit mode.  You removed the exact check for that, using HF_CS64_MASK, quoted 
above.


r~