Newer AMD processors have a feature to virtualize the use of the SPEC_CTRL MSR on the guest. The series adds the feature support and enables the feature on SVM. --- v2: NOTE: This is not final yet. Sending out the patches to make sure I captured all the comments correctly.
1. Most of the changes are related to Jim and Sean's feedback. 2. Improved the description of patch #2. 3. Updated the vmcb save area's guest spec_ctrl value(offset 0x2E0) properly. Initialized during init_vmcb and svm_set_msr and returned the value from save area for svm_get_msr. 4. As Jim commented, transferred the value into the VMCB prior to VMRUN and out of the VMCB after #VMEXIT. 5. Added kvm-unit-test to detect the SPEC CTRL feature. https://lore.kernel.org/kvm/160865324865.19910.5159218511905134908.stgit@bmoger-ubuntu/ 6. Sean mantioned of renaming MSR_AMD64_VIRT_SPEC_CTRL. But, it might create even more confusion, so dropped the idea for now. v1: https://lore.kernel.org/kvm/160738054169.28590.5171339079028237631.stgit@bmoger-ubuntu/ --- Babu Moger (2): x86/cpufeatures: Add the Virtual SPEC_CTRL feature KVM: SVM: Add support for Virtual SPEC_CTRL arch/x86/include/asm/cpufeatures.h | 1 + arch/x86/include/asm/svm.h | 4 +++- arch/x86/kvm/svm/svm.c | 29 +++++++++++++++++++++++++---- 3 files changed, 29 insertions(+), 5 deletions(-) --