KVM: Don't allow lmsw to clear cr0.pe

The current lmsw implementation allows the guest to clear cr0.pe, contrary
to the manual, which breaks EMM386.EXE.

Fix by ORing the old cr0.pe with lmsw's operand.

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

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 474a27fc42df252aac95cf07835b017393ba7179..fa1c51925597ddd71aff934c85d9ba74883b7dad 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -470,7 +470,7 @@ EXPORT_SYMBOL_GPL(kvm_set_cr0);
 
 void kvm_lmsw(struct kvm_vcpu *vcpu, unsigned long msw)
 {
-       kvm_set_cr0(vcpu, kvm_read_cr0_bits(vcpu, ~0x0ful) | (msw & 0x0f));
+       kvm_set_cr0(vcpu, kvm_read_cr0_bits(vcpu, ~0x0eul) | (msw & 0x0f));
 }
 EXPORT_SYMBOL_GPL(kvm_lmsw);