On 09/01/2018 11:15, Thomas Gleixner wrote: > 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? Sorry, my mistake. I'll CC you on v2. Paolo
