From: Sean Christopherson Date: Mon, 2 Mar 2020 23:57:07 +0000 (-0800) Subject: KVM: nSVM: Expose SVM features to L1 iff nested is enabled X-Git-Tag: Ubuntu-5.13.0-19.19~6350^2~78 X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=a50718cc3f43f12e6e33b098b5e2a9eb19f13158;p=mirror_ubuntu-jammy-kernel.git KVM: nSVM: Expose SVM features to L1 iff nested is enabled Set SVM feature bits in KVM capabilities if and only if nested=true, KVM shouldn't advertise features that realistically can't be used. Use kvm_cpu_cap_has(X86_FEATURE_SVM) to indirectly query "nested" in svm_set_supported_cpuid() in anticipation of moving CPUID 0x8000000A adjustments into common x86 code. Suggested-by: Paolo Bonzini Signed-off-by: Sean Christopherson Signed-off-by: Paolo Bonzini --- diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 5e3261ec8c59..76a480a37f1d 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -1371,21 +1371,21 @@ static __init void svm_set_cpu_caps(void) { kvm_set_cpu_caps(); - /* CPUID 0x80000001 */ - if (nested) + /* CPUID 0x80000001 and 0x8000000A (SVM features) */ + if (nested) { kvm_cpu_cap_set(X86_FEATURE_SVM); + if (boot_cpu_has(X86_FEATURE_NRIPS)) + kvm_cpu_cap_set(X86_FEATURE_NRIPS); + + if (npt_enabled) + kvm_cpu_cap_set(X86_FEATURE_NPT); + } + /* CPUID 0x80000008 */ if (boot_cpu_has(X86_FEATURE_LS_CFG_SSBD) || boot_cpu_has(X86_FEATURE_AMD_SSBD)) kvm_cpu_cap_set(X86_FEATURE_VIRT_SSBD); - - /* CPUID 0x8000000A */ - /* Support next_rip if host supports it */ - kvm_cpu_cap_check_and_set(X86_FEATURE_NRIPS); - - if (npt_enabled) - kvm_cpu_cap_set(X86_FEATURE_NPT); } static __init int svm_hardware_setup(void) @@ -6055,6 +6055,10 @@ static void svm_set_supported_cpuid(struct kvm_cpuid_entry2 *entry) { switch (entry->function) { case 0x8000000A: + if (!kvm_cpu_cap_has(X86_FEATURE_SVM)) { + entry->eax = entry->ebx = entry->ecx = entry->edx = 0; + break; + } entry->eax = 1; /* SVM revision 1 */ entry->ebx = 8; /* Lets support 8 ASIDs in case we add proper ASID emulation to nested SVM */