On Thu, Jan 9, 2025 at 9:30 AM Oleksii Kurochko <oleksii.kuroc...@gmail.com> wrote: > > > On 1/2/25 6:13 PM, Petr Beneš wrote: > > From: Petr Beneš <w1be...@gmail.com> > > Changes since v2: > - Reset entry->pw in all cases in p2m_set_entry, except for p2m_access_r_pw > > Changes since v1: > - Added signed-off-by tags > > This patch introduces a new XENMEM_access_r_pw permission. Functionally, it > is similar to XENMEM_access_r, but for processors with > TERTIARY_EXEC_EPT_PAGING_WRITE support (Intel 12th Gen/Alder Lake and later), > it also permits the CPU to write to the page during guest page-table walks > (e.g., updating A/D bits) without triggering an EPT violation. > > This behavior works by both enabling the EPT paging-write feature and setting > the EPT paging-write flag in the EPT leaf entry. > > This feature provides a significant performance boost for introspection tools > that monitor guest page-table updates. Previously, every page-table > modification by the guest—including routine updates like setting A/D > bits—triggered an EPT violation, adding unnecessary overhead. The new > XENMEM_access_r_pw permission allows these "uninteresting" updates to occur > without EPT violations, improving efficiency. > > Considering that this feature provides a significant performance boost for > introspection tools probably we could consider to take it to current release. > > I see that the patch series was acked-by "Acked-by: Tamas K Lengyel > <ta...@tklengyel.com>" but based on the change log it is not clear when > exactly > > before Feature freeze date or not. ( and I don't see any reply from Tamas ).
I've acked the patch Thu, Dec 19, 2024. Cheers, Tamas
