Re: [Xen-devel] [PATCH v3 03/13] VMX: implement suppress #VE.

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 10.07.15 at 21:30, <ravi.sahita@xxxxxxxxx> wrote:
>> From: Jan Beulich [mailto:JBeulich@xxxxxxxx]
>>Sent: Thursday, July 09, 2015 6:01 AM
>>>>> On 01.07.15 at 20:09, <edmund.h.white@xxxxxxxxx> wrote:
>>> @@ -232,6 +235,15 @@ static int ept_set_middle_entry(struct p2m_domain
>>> @@ -1134,6 +1151,13 @@ int ept_p2m_init(struct p2m_domain *p2m)
>>>          p2m->flush_hardware_cached_dirty = ept_flush_pml_buffers;
>>>      }
>>>
>>> +    table =
>>> + map_domain_page(pagetable_get_pfn(p2m_get_pagetable(p2m)));
>>> +
>>> +    for ( i = 0; i < EPT_PAGETABLE_ENTRIES; i++ )
>>> +        table[i].suppress_ve = 1;
>>> +
>>> +    unmap_domain_page(table);
>>
>>... why is this needed? Bit 63 is documented to be ignored in PML4Es (just 
> like
>>in all other intermediate page tables).
> 
> Valid point - this has no negative side-effects per se so we didn't change 
> this.

Taking "we didn't change this" to refer to v3 -> v4, I still think this
should be dropped if it isn't needed. There can only be confusion
arising from code having no purpose.

Jan


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