Comment 3 for bug 1743362

Vincent Bernat (vbernat) wrote :

As mentioned in #1742995, one patch is incomplete and doesn't expose the appropriate CPUID for KVM hosts when running on Intel hardware. 8339cae23d79be97a38df3852ef5dab870806a58 should add speculative control CPUID support for guests. The patch looks truncated as it defines KVM_CPUID_BIT_SPEC_CTRL but doesn't use it. I am using this patch instead: https://github.com/exoscale/pkg-kernel-4.4/blob/xenial/debian/patches/ibrs%2Bkvm/0002-kvm-x86-add-speculative-control-cpuid-support-for-guests.patch. The additional bits compared to the patch from SuSE (https://github.com/openSUSE/kernel-source/blob/SLE12-SP3/patches.suse/27-kvm-x86-add-speculative-control-cpuid-support-for-guests.patch) are needed because this is the first time a CPUID 7.0 feature is exposed on EDX.