Re: [PATCH v3] x86/HVM: add padding to struct hvm_hw_cpu

["Roger Pau Monné" <roger.pau@citrix.com>]

El 19/01/16 a les 16.13, Jan Beulich ha escrit:
>>>> On 18.01.16 at 17:25, <roger.pau@citrix.com> wrote:
>> --- a/xen/arch/x86/hvm/hvm.c
>> +++ b/xen/arch/x86/hvm/hvm.c
>> @@ -1990,6 +1990,9 @@ static int hvm_load_cpu_ctxt(struct domain *d, hvm_domain_context_t *h)
>>      if ( hvm_load_entry_zeroextend(CPU, h, &ctxt) != 0 )
>>          return -EINVAL;
>>  
>> +    if ( ctxt.pad0 != 0 )
>> +        return -EINVAL;
> 
> Right after I had committed and pushed the patch it occurred to
> me that this seems to be missing a save side counterpart, which
> would constitute both an information leak and a functional bug.
> Would you please take another look?

Sure, thanks for realising! Now that you make me look at it
hvm_save_cpu_ctxt should zero hvm_hw_cpu on each iteration, IMHO the
current code is asking for trouble. I will send a patch ASAP.

Roger.