Re: [Xen-devel] [PATCH] x86/VMX: sanitize VM86 TSS handling

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 14.02.17 at 18:35, <tim@xxxxxxx> wrote:
> At 06:37 -0700 on 13 Feb (1486967832), Jan Beulich wrote:
>> >>> On 13.02.17 at 14:19, <JBeulich@xxxxxxxx> wrote:
>> > -    tss = mem_alloc(128, 128);
>> > -    memset(tss, 0, 128);
>> > +    tss = mem_alloc(TSS_SIZE, TSS_SIZE);
>> 
>>     tss = mem_alloc(TSS_SIZE, 128);
>> 
>> is sufficient here, as I've noticed (only) while reviewing Roger's
>> series v4 of which did trigger the creation of this patch. I've made
>> the change locally for now.
> 
> Should Xen check the alignment when the param gets written?

I did think about this too, but then decided not to, since the guest
would only shoot itself in the foot (the more that in non-root mode
no actual task switching by the hardware occurs, so the alignment
requirement is pretty theoretical anyway).

Jan


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