Commit a50718cc authored by Sean Christopherson's avatar Sean Christopherson Committed by Paolo Bonzini
Browse files

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: default avatarPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarSean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 91661989

arch/x86/kvm/svm.c

+13 −9
Original line number Diff line number Diff line
@@ -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 */

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