KVM: X86: Introduce generic guest-mode representation

This patch introduces a generic representation of guest-mode
fpr a vcpu. This currently only exists in the SVM code.
Having this representation generic will help making the
non-svm code aware of nesting when this is necessary.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

arch/x86/include/asm/kvm_host.h

@@ -779,6 +779,7 @@ enum {
 #define HF_VINTR_MASK		(1 << 2)
 #define HF_NMI_MASK		(1 << 3)
 #define HF_IRET_MASK		(1 << 4)
+#define HF_GUEST_MASK		(1 << 5) /* VCPU is in guest-mode */
 
 /*
  * Hardware virtualization extension instructions may fault if a

arch/x86/kvm/kvm_cache_regs.h

@@ -84,4 +84,19 @@ static inline u64 kvm_read_edx_eax(struct kvm_vcpu *vcpu)
 		| ((u64)(kvm_register_read(vcpu, VCPU_REGS_RDX) & -1u) << 32);
 }
 
+static inline void enter_guest_mode(struct kvm_vcpu *vcpu)
+{
+	vcpu->arch.hflags |= HF_GUEST_MASK;
+}
+
+static inline void leave_guest_mode(struct kvm_vcpu *vcpu)
+{
+	vcpu->arch.hflags &= ~HF_GUEST_MASK;
+}
+
+static inline bool is_guest_mode(struct kvm_vcpu *vcpu)
+{
+	return vcpu->arch.hflags & HF_GUEST_MASK;
+}
+
 #endif