Acquire SRCU for read when handling fastpath MSR writes so that side effects like Note, the PMU case could (and should) also be fixed by making the PMU filter code smarter, e.g. by snapshotting which PMC events need to be emulated, thus avoiding the filter lookup entirely. But acquiring SRCU is relatively cheap, and this isn't the first bug of this nature. Which is a perfect segue into patch 2, which reverts a hack-a-fix to fudge around SVM needing to do the front half of emulation when skipping the WRMSR. Note #2, the fastpath also doesn't honor the MSR filter for TSC_DEADLINE. That's a problem for another day. Sean Christopherson (2): KVM: x86: Acquire SRCU read lock when handling fastpath MSR writes Revert "KVM: SVM: Skip WRMSR fastpath on VM-Exit if next RIP isn't valid" arch/x86/kvm/svm/svm.c | 10 ++-------- arch/x86/kvm/x86.c | 4 ++++ 2 files changed, 6 insertions(+), 8 deletions(-) base-commit: fdf0eaf11452d72945af31804e2a1048ee1b574c -- 2.41.0.487.g6d72f3e995-goog