Advertise DecodeAssists to L1 now that KVM virtualizes the guest-visible DecodeAssist state in VMCB12: EXITINFO1 decode data for MOV CR/DR, INTn, and INVLPG exits, plus instruction bytes for nested page faults and intercepted #PF exits. INVLPGA's linear address remains available directly from the saved guest rAX, as required by the APM.
Expose the feature only when supported by hardware, as KVM still relies on hardware DecodeAssists for VM-Exits that are reflected directly from L2. With DecodeAssists exposed, QEMU configurations that require the feature (e.g. "-cpu ...,+decodeassists,...,enforce") are no longer rejected. Signed-off-by: Tina Zhang <[email protected]> --- arch/x86/kvm/svm/svm.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 2c04a8d9da29..4af5121070f4 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -5518,6 +5518,8 @@ static __init void svm_set_cpu_caps(void) */ kvm_cpu_cap_set(X86_FEATURE_FLUSHBYASID); + kvm_cpu_cap_check_and_set(X86_FEATURE_DECODEASSISTS); + if (nrips) kvm_cpu_cap_set(X86_FEATURE_NRIPS); -- 2.43.7
