KVM/x86: pmu: Fix #GP condition check for RDPMC emulation

In guest protected mode, if the current privilege level
is not 0 and the PCE flag in the CR4 register is cleared,
we will inject a #GP for RDPMC usage.
Signed-off-by: Like Xu <like.xu@linux.intel.com>
Message-Id: <20200708074409.39028-1-like.xu@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/pmu.c

@@ -372,6 +372,11 @@ int kvm_pmu_rdpmc(struct kvm_vcpu *vcpu, unsigned idx, u64 *data)
 	if (!pmc)
 		return 1;
 
+	if (!(kvm_read_cr4(vcpu) & X86_CR4_PCE) &&
+	    (kvm_x86_ops.get_cpl(vcpu) != 0) &&
+	    (kvm_read_cr0(vcpu) & X86_CR0_PE))
+		return 1;
+
 	*data = pmc_read_counter(pmc) & mask;
 	return 0;
 }