KVM: nested VMX: disable perf cpuid reporting (bc613494) · Commits · 戴 / test

Initilization of L2 guest with -cpu host, on L1 guest with -cpu host triggers: (qemu) KVM: entry failed, hardware error 0x7 ... nested_vmx_run: VMCS MSR_{LOAD,STORE} unsupported Nested VMX MSR load/store support is not sufficient to allow perf for L2 guest. Until properly fixed, trap CPUID and disable function 0xA. Signed-off-by:

Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by:

Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/cpuid.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -774,6 +774,12 @@ void kvm_cpuid(struct kvm_vcpu vcpu, u32 eax, u32 ebx, u32 ecx, u32 *edx)
		if (!best)
		best = check_cpuid_limit(vcpu, function, index);

		/*
		* Perfmon not yet supported for L2 guest.
		*/
		if (is_guest_mode(vcpu) && function == 0xa)
		best = NULL;

		if (best) {
		*eax = best->eax;
		*ebx = best->ebx;

arch/x86/kvm/vmx.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -6986,6 +6986,8 @@ static bool nested_vmx_exit_handled(struct kvm_vcpu *vcpu)
		case EXIT_REASON_TASK_SWITCH:
		return 1;
		case EXIT_REASON_CPUID:
		if (kvm_register_read(vcpu, VCPU_REGS_RAX) == 0xa)
		return 0;
		return 1;
		case EXIT_REASON_HLT:
		return nested_cpu_has(vmcs12, CPU_BASED_HLT_EXITING);

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