Re: [Xen-devel] [PATCH v5 4/9] xen/x86: populate PVHv2 Dom0 physical memory map

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 20.01.17 at 20:41, <andrew.cooper3@xxxxxxxxxx> wrote:
> On 19/01/17 17:29, Roger Pau Monne wrote:
>> +    tss = map_domain_gfn(p2m_get_hostp2m(d), _gfn(PFN_DOWN(gaddr)),
>> +                         &mfn, &p2mt, 0, &rc);
>> +    if ( tss == NULL )
>> +    {
>> +        printk("Unable to map VM86 TSS area\n");
>> +        return 0;
>> +    }
>> +
>> +    memset(tss, 0, HVM_VM86_TSS_SIZE);
> 
> Do we actually need to 0 this?  Don't we guarantee to hand out zero'd
> pages during construction?  (I can't actually recall.  Perhaps it is
> better to explicitly clear it.)

No, we don't zero before handing out, we zero after a reclaiming
memory from a dying guest or from the hypervisor.

Jan


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