[PATCH] KVM: fix lockup on 32-bit intel hosts with nx disabled in the…

… bios

Intel hosts, without long mode, and with nx support disabled in the bios
have an efer that is readable but not writable.  This causes a lockup on
switch to guest mode (even though it should exit with reason 34 according
to the documentation).

Signed-off-by: Avi Kivity <avi@qumranet.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/kvm/vmx.c

@@ -1116,6 +1116,8 @@ static int vmx_vcpu_setup(struct kvm_vcpu *vcpu)
 
 		if (rdmsr_safe(index, &data_low, &data_high) < 0)
 			continue;
+		if (wrmsr_safe(index, data_low, data_high) < 0)
+			continue;
 		data = data_low | ((u64)data_high << 32);
 		vcpu->host_msrs[j].index = index;
 		vcpu->host_msrs[j].reserved = 0;