Paolo Bonzini <pbonzini@xxxxxxxxxx> writes: > On 11/02/21 22:22, Bandan Das wrote: >> The pcid-disabled test from kvm-unit-tests fails on a Milan host because the >> processor injects a #GP while the test expects #UD. While setting the intercept >> when the guest has it disabled seemed like the obvious thing to do, Babu Moger (AMD) >> pointed me to an earlier discussion here - https://lkml.org/lkml/2020/6/11/949 >> >> Jim points out there that #GP has precedence over the intercept bit when invpcid is >> called with CPL > 0 and so even if we intercept invpcid, the guest would end up with getting >> and "incorrect" exception. To inject the right exception, I created an entry for the instruction >> in the emulator to decode it successfully and then inject a UD instead of a GP when >> the guest has it disabled. >> >> Bandan Das (3): >> KVM: Add a stub for invpcid in the emulator table >> KVM: SVM: Handle invpcid during gp interception >> KVM: SVM: check if we need to track GP intercept for invpcid >> >> arch/x86/kvm/emulate.c | 3 ++- >> arch/x86/kvm/svm/svm.c | 22 +++++++++++++++++++++- >> 2 files changed, 23 insertions(+), 2 deletions(-) >> > > Isn't this the same thing that "[PATCH 1/3] KVM: SVM: Intercept > INVPCID when it's disabled to inject #UD" also does? > Yeah, Babu pointed me to Sean's series after I posted mine. 1/3 indeed will fix the kvm-unit-test failure. IIUC, It doesn't look like it handles the case for the guest executing invpcid at CPL > 0 when it's disabled for the guest - #GP takes precedence over intercepts and will be incorrectly injected instead of an #UD. Bandan > Paolo
