Re: [PATCH v10 0/9] Linear Address Masking (LAM) KVM Enabling

From: Zeng Guang
Date: Fri Aug 25 2023 - 10:20:17 EST



On 8/18/2023 9:53 PM, Sean Christopherson wrote:
On Fri, Aug 18, 2023, Binbin Wu wrote:
On 8/17/2023 5:17 PM, Binbin Wu wrote:
On 8/17/2023 6:25 AM, Sean Christopherson wrote:
On Wed, Jul 19, 2023, Binbin Wu wrote:
Binbin Wu (7):
   KVM: x86/mmu: Use GENMASK_ULL() to define __PT_BASE_ADDR_MASK
   KVM: x86: Add & use kvm_vcpu_is_legal_cr3() to check CR3's legality
   KVM: x86: Use KVM-governed feature framework to track "LAM enabled"
   KVM: x86: Virtualize CR3.LAM_{U48,U57}
   KVM: x86: Introduce get_untagged_addr() in kvm_x86_ops and
call it in
     emulator
   KVM: VMX: Implement and wire get_untagged_addr() for LAM
   KVM: x86: Untag address for vmexit handlers when LAM applicable

Robert Hoo (2):
   KVM: x86: Virtualize CR4.LAM_SUP
   KVM: x86: Expose LAM feature to userspace VMM
Looks good, just needs a bit of re-organination.  Same goes for the
LASS series.

For the next version, can you (or Zeng) send a single series for LAM
and LASS?
They're both pretty much ready to go, i.e. I don't expect one to
hold up the other
at this point, and posting a single series will reduce the
probability of me
screwing up a conflict resolution or missing a dependency when applying.

Hi Sean,
Do you still prefer a single series for LAM and LASS  for the next version
when we don't need to rush for v6.6?
Yes, if it's not too much trouble on your end. Since the two have overlapping
prep work and concepts, and both series are in good shape, my strong preference
is to grab them at the same time. I would much rather apply what you've tested
and reduce the probability of messing up any conflicts.



Hi Sean,
One more concern, KVM LASS patch has an extra dependency on kernel LASS series in which
enumerates lass feature bit (X86_FEATURE_LASS/X86_CR4_LASS). So far kernel lass patch is
still under review, as alternative we may extract relevant patch part along with kvm lass patch
set for a single series in case kernel lass cannot be merged before v6.7.
Do you think it OK in that way?