Re: [Xen-devel] [PATCH v2 12/13] fuzz/x86_emulate: Set and fuzz more CPU state

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 25.09.17 at 16:26, <george.dunlap@xxxxxxxxxx> wrote:
> @@ -597,6 +599,47 @@ static const struct x86_emulate_ops all_fuzzer_ops = {
>  };
>  #undef SET
>  
> +static void _set_fpu_state(char *fxsave, bool store)
> +{
> +    if ( cpu_has_fxsr )
> +    {
> +        static union __attribute__((__aligned__(16))) {
> +            char x[464];
> +            struct {
> +                uint32_t other[6];
> +                uint32_t mxcsr;
> +                uint32_t mxcsr_mask;
> +                /* ... */
> +            };
> +        } *fxs;
> +
> +        fxs = (typeof(fxs)) fxsave;
> +
> +        if ( store ) {
> +            char null[512] __attribute__((aligned(16))) = { 0 };
> +            asm volatile(" fxrstor %0; "::"m"(*null));
> +            asm volatile(" fxrstor %0; "::"m"(*fxsave));
> +        }
> +        
> +        asm volatile( "fxsave %0" : "=m" (*fxs) );
> +
> +        if ( fxs->mxcsr_mask )
> +            mxcsr_mask = fxs->mxcsr_mask;
> +        else
> +            mxcsr_mask = 0x000ffbf;

Actually - why is this necessary? I.e. why isn't emul_test_init()
setting mxcsr_mask sufficient?

Jan


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
https://lists.xen.org/xen-devel