On 2/12/19 2:38 PM, Venkatesh Srinivas wrote: > On Tue, Feb 12, 2019 at 12:12 PM Singh, Brijesh <brijesh.singh@xxxxxxx> wrote: >> 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 > Do you mean Errata #1096? > (https://www.amd.com/system/files/TechDocs/55449_Fam_17h_M_00h-0Fh_Rev_Guide.pdf > v1.12 pg 61) Yes, I did noticed after sending the patch. Will fix in next rev. >>>> 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 > Should the pr_err() be ratelimited? Otherwise a guest suppressing #GP > could spam the host dmesg. Agree, ratelimited is good idea to suppressing the spam of host dmesg. Will use it in next rev. thanks -Brijesh > Thanks, > -- vs;
