Re: [PATCH 0/9] KVM: SVM: Fix and clean up "can emulate" mess

[Paolo Bonzini]

On 1/20/22 02:07, Sean Christopherson wrote:
> Revert an amusing/embarassing goof reported by Liam Merwick, where KVM
> attempts to determine if RIP is backed by a valid memslot without first
> translating RIP to its associated GPA/GFN.  Fix the underlying bug that
> was "fixed" by the misguided memslots check by (a) never rejecting
> emulation for !SEV guests and (b) using the #NPF error code to determine
> if the fault happened on the code fetch or on guest page tables, which is
> effectively what the memslots check attempted to do.
>
> Further clean up, harden, and document SVM's "can emulate" helper, and
> fix a #GP interception SEV bug found in the process of doing so.
>
> Sean Christopherson (9):
>    KVM: SVM: Never reject emulation due to SMAP errata for !SEV guests
>    Revert "KVM: SVM: avoid infinite loop on NPF from bad address"
>    KVM: SVM: Don't intercept #GP for SEV guests
>    KVM: SVM: Explicitly require DECODEASSISTS to enable SEV support
>    KVM: x86: Pass emulation type to can_emulate_instruction()
>    KVM: SVM: WARN if KVM attempts emulation on #UD or #GP for SEV guests
>    KVM: SVM: Inject #UD on attempted emulation for SEV guest w/o insn
>      buffer
>    KVM: SVM: Don't apply SEV+SMAP workaround on code fetch or PT access
>    KVM: SVM: Don't kill SEV guest if SMAP erratum triggers in usermode
>
>   arch/x86/include/asm/kvm_host.h |   3 +-
>   arch/x86/kvm/svm/sev.c          |   9 +-
>   arch/x86/kvm/svm/svm.c          | 162 ++++++++++++++++++++++----------
>   arch/x86/kvm/vmx/vmx.c          |   7 +-
>   arch/x86/kvm/x86.c              |  11 ++-
>   virt/kvm/kvm_main.c             |   1 -
>   6 files changed, 135 insertions(+), 58 deletions(-)
>
>
> base-commit: edb9e50dbe18394d0fc9d0494f5b6046fc912d33

Queued, thanks.

Paolo