On Thu, 2023-02-09 at 14:15 +0800, Chao Gao wrote: > On Thu, Feb 09, 2023 at 10:40:13AM +0800, Robert Hoo wrote: > > Intercept CR4.LAM_SUP by KVM, to avoid read VMCS field every time, > > with > > expectation that guest won't toggle this bit frequently. > > > > Under EPT mode, CR3 is fully under guest control, guest LAM is thus > > transparent to > > KVM. Nothing more need to do. > > I don't think it is correct. You have to strip LAM_U57/U48 from CR3 > when > walking guest page table and strip metadata from pointers when > emulating > instructions. > Yes, has added patch 8 for emulation case. Didn't explicitly note it in cover letter. > > > > For Shadow paging (EPT = off), KVM need to handle guest CR3.LAM_U48 > > and CR3.LAM_U57 > > toggles. > > > > [1] ISE Chap10 https://cdrdv2.intel.com/v1/dl/getContent/671368 > > (Section 10.6 VMX interaction) > > [2] Thus currently, Kernel enabling patch only enables LAM_U57. > > https://lore.kernel.org/lkml/20230123220500.21077-1-kirill.shutemov@xxxxxxxxxxxxxxx/ > > > > Please add a kvm-unit-test or kselftest for LAM, particularly for > operations (e.g., canonical check for supervisor pointers, toggle > CR4.LAM_SUP) which aren't covered by the test in Kirill's series. OK, I can explore for kvm-unit-test in separate patch set. BTW, this patch set has passed guest running Kirill's kselftests.
