On 2/12/19 11:41 AM, Jim Mattson wrote: > On Tue, Feb 12, 2019 at 6:44 AM Singh, Brijesh <brijesh.singh@xxxxxxx> wrote: >> >> Errata#1090: >> >> On a nested data page fault when CR.SMAP=1 and the guest data read >> generates a SMAP violation, GuestInstrBytes field of the VMCB on a >> VMEXIT will incorrectly return 0h instead the correct guest >> instruction bytes . >> >> Recommend Workaround: >> >> To determine what instruction the guest was executing the hypervisor >> will have to decode the instruction at the instruction pointer. >> >> The recommended workaround can not be implemented for the SEV >> guest because guest memory is encrypted with the guest specific key, >> and instruction decoder will not be able to decode the instruction >> bytes. If we hit this errata in the SEV guest then inject #GP into >> the guest and log the message. >> >> Cc: Jim Mattson <jmattson@xxxxxxxxxx> >> Cc: Tom Lendacky <thomas.lendacky@xxxxxxx> >> Cc: Borislav Petkov <bp@xxxxxxxxx> >> Cc: Joerg Roedel <joro@xxxxxxxxxx> >> Cc: "Radim Krčmář" <rkrcmar@xxxxxxxxxx> >> Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx> >> Signed-off-by: Brijesh Singh <brijesh.singh@xxxxxxx> > > This was ... > Reported-by: Venkatesh Srinivas <venkateshs@xxxxxxxxxx> > I will add the tag in next rev. > I'm curious why you chose to inject #GP rather than, say, requesting a > guest shutdown. Is the guest #GP handler expected to be able to > recover from this? > We will *not* be able to recover from this, I wanted to abort the guest and I should admit that I was not ware of requesting a SHUTDOWN method so decided to inject #GP so that guest does not continue. Browsing further, I see that kvm_make_request(KVM_REQ_TRIPLE_FAULT, vcpu) can be used to request a SHUTDOWN. I will use it in next rev. thanks for the hint . -Brijeshh
