Add direct access to speculation control MSRs for KVM guests. This allows the guest to protect itself against Spectre V2 using IBRS+IBPB instead of a retpoline+IBPB based approach.
It also exposes the ARCH_CAPABILITIES MSR which is going to be used by future Intel processors to indicate RDCL_NO and IBRS_ALL. v5: - svm: add PRED_CMD and SPEC_CTRL to direct_access_msrs list. - vmx: check also for X86_FEATURE_SPEC_CTRL for msr reads and writes. - vmx: Use MSR_TYPE_W instead of MSR_TYPE_R for the nested IBPB MSR - rewrite commit message for IBPB patch [2/5] (Ashok) v4: - Add IBRS passthrough for SVM (5/5). - Handle nested guests properly. - expose F(IBRS) in kvm_cpuid_8000_0008_ebx_x86_features Ashok Raj (1): KVM: x86: Add IBPB support KarimAllah Ahmed (4): KVM: x86: Update the reverse_cpuid list to include CPUID_7_EDX KVM: VMX: Emulate MSR_IA32_ARCH_CAPABILITIES KVM: VMX: Allow direct access to MSR_IA32_SPEC_CTRL KVM: SVM: Allow direct access to MSR_IA32_SPEC_CTRL arch/x86/kvm/cpuid.c | 22 +++++++--- arch/x86/kvm/cpuid.h | 1 + arch/x86/kvm/svm.c | 87 ++++++++++++++++++++++++++++++++++++++ arch/x86/kvm/vmx.c | 117 +++++++++++++++++++++++++++++++++++++++++++++++++-- arch/x86/kvm/x86.c | 1 + 5 files changed, 218 insertions(+), 10 deletions(-) Cc: Andi Kleen <[email protected]> Cc: Andrea Arcangeli <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Arjan van de Ven <[email protected]> Cc: Ashok Raj <[email protected]> Cc: Asit Mallick <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Dan Williams <[email protected]> Cc: Dave Hansen <[email protected]> Cc: David Woodhouse <[email protected]> Cc: Greg Kroah-Hartman <[email protected]> Cc: H. Peter Anvin <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Janakarajan Natarajan <[email protected]> Cc: Joerg Roedel <[email protected]> Cc: Jun Nakajima <[email protected]> Cc: Laura Abbott <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Masami Hiramatsu <[email protected]> Cc: Paolo Bonzini <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Radim Krčmář <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Tim Chen <[email protected]> Cc: Tom Lendacky <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] -- 2.7.4
