Re: [PATCH v5] KVM: x86: avoid large stack allocations in em_fxrstor

[Nick Desaulniers]

On Wed, May 31, 2017 at 07:01:29AM -0400, Paolo Bonzini wrote:
> > +		size = offsetof(struct fxregs_state, xmm_space[16]);
> This still has the same issue (it should be multiplied by 4).

I'm still misunderstanding the math here.

Why multiplied by four, in this case? 8 * 16 / 4 is used in other cases.

Also, previously Radim wrote:

>> +      size = offsetof(struct fxregs_state, xmm_space[8]);
> This should be the size of first 8 XMM registers, but xmm_space is of
> type u32, so the correct size is
>   xmm_space[8 * 16/sizeof(*fx_state.xmm_space)].

So I think my calculation is off in xmm_offset still?  Can we make use
of well-named variables, in place of these constants? Otherwise the math
is hard to follow.

> Thanks Nick for the patches and Radim for the reviews!
> Paolo

Thanks for the code review!