Messages in this thread |  | | Date | Thu, 5 Jan 2023 15:46:13 -0600 | Subject | Re: [PATCH Part2 v6 07/49] x86/sev: Invalid pages from direct map when adding it to RMP table | From | "Kalra, Ashish" <> |
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Hello Boris,
On 12/29/2022 11:09 AM, Borislav Petkov wrote: > On Tue, Dec 27, 2022 at 03:49:39PM -0600, Kalra, Ashish wrote: >> Milan onward, > > And before ML there's no SNP, right? >
Yes, that's correct.
>> there is H/W support for coherency between mappings of the >> same physical page with different encryption keys, so AFAIK, there should be >> no need to flush during page state transitions, where we invoke these direct >> map interface functions for re-mapping/invalidating pages. > > Yah, that rings a bell. > > In any case, the fact that flushing is not needed should be stated > somewhere in text so that it is clear why. > >> I don't know if there is any other reason to flush after modifying >> the direct map ? > > There's > > /* > * No need to flush, when we did not set any of the caching > * attributes: > */ > cache = !!pgprot2cachemode(mask_set); > > > Does the above HW cover this case too?
Actually, as both set_memory_p() and set_memory_np() are only setting/clearing the _PAGE_PRESENT flag and not changing any of the page caching attributes so this flush won't be required anyway.
Thanks, Ashish
> > Thx. >
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