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Commit bc613494 authored by Marcelo Tosatti's avatar Marcelo Tosatti Committed by Paolo Bonzini
Browse files

KVM: nested VMX: disable perf cpuid reporting 



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: default avatarMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent a2b9e6c1

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);