Re: [PATCH Part2 RFC v2 08/37] x86/sev: Split the physmap when adding the page in RMP table

[Vlastimil Babka]

On 5/3/21 5:41 PM, Dave Hansen wrote:
> On 5/3/21 8:15 AM, Andy Lutomirski wrote:
>> How much performance do we get back if we add a requirement that only
>> 2M pages (hugetlbfs, etc) may be used for private guest memory?
> 
> Are you generally asking about the performance overhead of using 4k
> pages instead of 2M for the direct map?  We looked at that recently and
> pulled together some data:

IIUC using 2M for private guest memory wouldn't be itself sufficient, as the
guest would also have to share pages with host with 2MB granularity, and that
might be too restrictive?

>> https://lore.kernel.org/lkml/213b4567-46ce-f116-9cdf-bbd0c884eb3c@xxxxxxxxxxxxxxx/
>