KVM: Allow adjust_tsc_offset to be in host or guest cycles

Redefine the API to take a parameter indicating whether an
adjustment is in host or guest cycles.

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

arch/x86/include/asm/kvm_host.h

@@ -646,7 +646,7 @@ struct kvm_x86_ops {
 	u64 (*get_mt_mask)(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio);
 	int (*get_lpage_level)(void);
 	bool (*rdtscp_supported)(void);
-	void (*adjust_tsc_offset)(struct kvm_vcpu *vcpu, s64 adjustment);
+	void (*adjust_tsc_offset)(struct kvm_vcpu *vcpu, s64 adjustment, bool host);
 
 	void (*set_tdp_cr3)(struct kvm_vcpu *vcpu, unsigned long cr3);
 
@@ -676,6 +676,17 @@ struct kvm_arch_async_pf {
 
 extern struct kvm_x86_ops *kvm_x86_ops;
 
+static inline void adjust_tsc_offset_guest(struct kvm_vcpu *vcpu,
+					   s64 adjustment)
+{
+	kvm_x86_ops->adjust_tsc_offset(vcpu, adjustment, false);
+}
+
+static inline void adjust_tsc_offset_host(struct kvm_vcpu *vcpu, s64 adjustment)
+{
+	kvm_x86_ops->adjust_tsc_offset(vcpu, adjustment, true);
+}
+
 int kvm_mmu_module_init(void);
 void kvm_mmu_module_exit(void);
 

arch/x86/kvm/svm.c

@@ -1016,10 +1016,14 @@ static void svm_write_tsc_offset(struct kvm_vcpu *vcpu, u64 offset)
 	mark_dirty(svm->vmcb, VMCB_INTERCEPTS);
 }
 
-static void svm_adjust_tsc_offset(struct kvm_vcpu *vcpu, s64 adjustment)
+static void svm_adjust_tsc_offset(struct kvm_vcpu *vcpu, s64 adjustment, bool host)
 {
 	struct vcpu_svm *svm = to_svm(vcpu);
 
+	WARN_ON(adjustment < 0);
+	if (host)
+		adjustment = svm_scale_tsc(vcpu, adjustment);
+
 	svm->vmcb->control.tsc_offset += adjustment;
 	if (is_guest_mode(vcpu))
 		svm->nested.hsave->control.tsc_offset += adjustment;

arch/x86/kvm/vmx.c

@@ -1856,7 +1856,7 @@ static void vmx_write_tsc_offset(struct kvm_vcpu *vcpu, u64 offset)
 	}
 }
 
-static void vmx_adjust_tsc_offset(struct kvm_vcpu *vcpu, s64 adjustment)
+static void vmx_adjust_tsc_offset(struct kvm_vcpu *vcpu, s64 adjustment, bool host)
 {
 	u64 offset = vmcs_read64(TSC_OFFSET);
 	vmcs_write64(TSC_OFFSET, offset + adjustment);

arch/x86/kvm/x86.c

@@ -1116,7 +1116,7 @@ static int kvm_guest_time_update(struct kvm_vcpu *v)
 	if (vcpu->tsc_catchup) {
 		u64 tsc = compute_guest_tsc(v, kernel_ns);
 		if (tsc > tsc_timestamp) {
-			kvm_x86_ops->adjust_tsc_offset(v, tsc - tsc_timestamp);
+			adjust_tsc_offset_guest(v, tsc - tsc_timestamp);
 			tsc_timestamp = tsc;
 		}
 	}