KVM: Replace read accesses of vcpu->arch.cr0 by an accessor

Since we'd like to allow the guest to own a few bits of cr0 at times, we need
to know when we access those bits.

Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 7e8faea..0f89e32 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -1515,7 +1515,7 @@
 
 	/* syscall is not available in real mode */
 	if (c->lock_prefix || ctxt->mode == X86EMUL_MODE_REAL
-		|| !(ctxt->vcpu->arch.cr0 & X86_CR0_PE))
+	    || !kvm_read_cr0_bits(ctxt->vcpu, X86_CR0_PE))
 		return -1;
 
 	setup_syscalls_segments(ctxt, &cs, &ss);
@@ -1569,7 +1569,7 @@
 
 	/* inject #GP if in real mode or paging is disabled */
 	if (ctxt->mode == X86EMUL_MODE_REAL ||
-		!(ctxt->vcpu->arch.cr0 & X86_CR0_PE)) {
+	    !kvm_read_cr0_bits(ctxt->vcpu, X86_CR0_PE)) {
 		kvm_inject_gp(ctxt->vcpu, 0);
 		return -1;
 	}
@@ -1635,7 +1635,7 @@
 
 	/* inject #GP if in real mode or paging is disabled */
 	if (ctxt->mode == X86EMUL_MODE_REAL
-		|| !(ctxt->vcpu->arch.cr0 & X86_CR0_PE)) {
+	    || !kvm_read_cr0_bits(ctxt->vcpu, X86_CR0_PE)) {
 		kvm_inject_gp(ctxt->vcpu, 0);
 		return -1;
 	}