On Mon, 8 Jan 2018, Paolo Bonzini wrote: > This series allows guests to use the MSR_IA32_SPEC_CTRL and > MSR_IA32_PRED_CMD model specific registers that were added as mitigations > for CVE-2017-5715. > > These are only the KVM specific parts of the fix. It does *not* yet > include any protection for reading host memory from the guest, because > that would be done in the same way as the rest of Linux. So there is no > IBRS *usage* here, no retpolines, no stuffing of the return stack buffer. > (KVM already includes a fix to clear all registers on vmexit, which is > enough to block Google Project Zero's PoC exploit). > > However, I am including the changes to use IBPB (indirect branch > predictor barrier) if available. That occurs only when there is a VCPU > switch on a physical CPU, thus it has a small impact on performance. > > The patches are a bit hackish because the relevant cpufeatures have > not been included yet, and because I wanted to make the patches easier > to backport to distro kernels if desired, but I would still like to > have them in 4.16. > > Please review. CC'ing x86@xxxxxxxxxx on this would have been asked too much, right?
