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

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Date:   Thu, 20 Jan 2022 01:07:10 +0000
From:   Sean Christopherson <seanjc@...gle.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     Sean Christopherson <seanjc@...gle.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Tom Lendacky <thomas.lendacky@....com>,
        Brijesh Singh <brijesh.singh@....com>,
        Liam Merwick <liam.merwick@...cle.com>
Subject: [PATCH 0/9] KVM: SVM: Fix and clean up "can emulate" mess

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
-- 
2.34.1.703.g22d0c6ccf7-goog