KVM: Ignore the writes to MSR_K7_HWCR(3)

When CPUID Fn8000_0001_EAX reports 0x00100f22 Windows 7 x64 guest
tries to set bit 3 in MSRC001_0015 in nt!KiDisableCacheErrataSource
and fails. This patch will ignore this step and allow things to move
on without having to fake CPUID value.
Signed-off-by: NNicolae Mogoreanu <mogoreanu@gmail.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

arch/x86/kvm/x86.c

@@ -1547,6 +1547,7 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 data)
 	case MSR_K7_HWCR:
 		data &= ~(u64)0x40;	/* ignore flush filter disable */
 		data &= ~(u64)0x100;	/* ignore ignne emulation enable */
+		data &= ~(u64)0x8;	/* ignore TLB cache disable */
 		if (data != 0) {
 			pr_unimpl(vcpu, "unimplemented HWCR wrmsr: 0x%llx\n",
 				data);