On 07/06/20 05:43, Takuya Yoshikawa wrote: > I understand how this works for THP backed guest memory, but what > will happen to hugetlbfs backed guest memory? > > When a huge amount of system memory is reserved as the hugetlbfs > pool and QEMU is said to use pages from there by the -mem-path > option, is it safe to enable the nx_huge_pages mitigation? The erratum arises when the guest sets up two iTLB entries of different sizes for the same page. Using 4 KiB EPT pages for executable areas ensures that iTLB entries will all be for 4 KiB pages, independent of the page size from the guest's page tables. Therefore, even with hugetlbfs the EPT tables will be split. There's no requirement for EPT pages to be the same size as the host page tables. Thanks, Paolo
