KVM: x86: Replace call-back compute_tsc_offset() with a common function

Both VMX and SVM calculate the tsc-offset in the same way, so this
patch removes the call-back compute_tsc_offset() and replaces it with a
common function kvm_compute_tsc_offset().

Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

4 files changed, 12 insertions, 20 deletions

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index c5a3f3d66e90..672f960e8144 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -856,7 +856,6 @@ struct kvm_x86_ops {
         u64 (*read_tsc_offset)(struct kvm_vcpu *vcpu);
         void (*write_tsc_offset)(struct kvm_vcpu *vcpu, u64 offset);
 
-        u64 (*compute_tsc_offset)(struct kvm_vcpu *vcpu, u64 target_tsc);
         u64 (*read_l1_tsc)(struct kvm_vcpu *vcpu, u64 host_tsc);
 
         void (*get_exit_info)(struct kvm_vcpu *vcpu, u64 *info1, u64 *info2);
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index f6e49a6c9ab0..d99b175ffbea 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -1004,15 +1004,6 @@ static void svm_adjust_tsc_offset(struct kvm_vcpu *vcpu, s64 adjustment, bool ho
         mark_dirty(svm->vmcb, VMCB_INTERCEPTS);
 }
 
-static u64 svm_compute_tsc_offset(struct kvm_vcpu *vcpu, u64 target_tsc)
-{
-        u64 tsc;
-
-        tsc = kvm_scale_tsc(vcpu, rdtsc());
-
-        return target_tsc - tsc;
-}
-
 static void init_vmcb(struct vcpu_svm *svm)
 {
         struct vmcb_control_area *control = &svm->vmcb->control;
@@ -4370,7 +4361,6 @@ static struct kvm_x86_ops svm_x86_ops = {
         .read_tsc_offset = svm_read_tsc_offset,
         .write_tsc_offset = svm_write_tsc_offset,
         .adjust_tsc_offset = svm_adjust_tsc_offset,
-        .compute_tsc_offset = svm_compute_tsc_offset,
         .read_l1_tsc = svm_read_l1_tsc,
 
         .set_tdp_cr3 = set_tdp_cr3,
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index baee46893899..2d4782ce9a93 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2426,11 +2426,6 @@ static void vmx_adjust_tsc_offset(struct kvm_vcpu *vcpu, s64 adjustment, bool ho
                                            offset + adjustment);
 }
 
-static u64 vmx_compute_tsc_offset(struct kvm_vcpu *vcpu, u64 target_tsc)
-{
-        return target_tsc - rdtsc();
-}
-
 static bool guest_cpuid_has_vmx(struct kvm_vcpu *vcpu)
 {
         struct kvm_cpuid_entry2 *best = kvm_find_cpuid_entry(vcpu, 1, 0);
@@ -10813,7 +10808,6 @@ static struct kvm_x86_ops vmx_x86_ops = {
         .read_tsc_offset = vmx_read_tsc_offset,
         .write_tsc_offset = vmx_write_tsc_offset,
         .adjust_tsc_offset = vmx_adjust_tsc_offset,
-        .compute_tsc_offset = vmx_compute_tsc_offset,
         .read_l1_tsc = vmx_read_l1_tsc,
 
         .set_tdp_cr3 = vmx_set_cr3,
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index c314e8d22a67..bb46066e125b 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1392,6 +1392,15 @@ u64 kvm_scale_tsc(struct kvm_vcpu *vcpu, u64 tsc)
 }
 EXPORT_SYMBOL_GPL(kvm_scale_tsc);
 
+static u64 kvm_compute_tsc_offset(struct kvm_vcpu *vcpu, u64 target_tsc)
+{
+        u64 tsc;
+
+        tsc = kvm_scale_tsc(vcpu, rdtsc());
+
+        return target_tsc - tsc;
+}
+
 void kvm_write_tsc(struct kvm_vcpu *vcpu, struct msr_data *msr)
 {
         struct kvm *kvm = vcpu->kvm;
@@ -1403,7 +1412,7 @@ void kvm_write_tsc(struct kvm_vcpu *vcpu, struct msr_data *msr)
         u64 data = msr->data;
 
         raw_spin_lock_irqsave(&kvm->arch.tsc_write_lock, flags);
-        offset = kvm_x86_ops->compute_tsc_offset(vcpu, data);
+        offset = kvm_compute_tsc_offset(vcpu, data);
         ns = get_kernel_ns();
         elapsed = ns - kvm->arch.last_tsc_nsec;
 
@@ -1460,7 +1469,7 @@ void kvm_write_tsc(struct kvm_vcpu *vcpu, struct msr_data *msr)
                 } else {
                         u64 delta = nsec_to_cycles(vcpu, elapsed);
                         data += delta;
-                        offset = kvm_x86_ops->compute_tsc_offset(vcpu, data);
+                        offset = kvm_compute_tsc_offset(vcpu, data);
                         pr_debug("kvm: adjusted tsc offset by %llu\n", delta);
                 }
                 matched = true;
@@ -2687,7 +2696,7 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
                 if (tsc_delta < 0)
                         mark_tsc_unstable("KVM discovered backwards TSC");
                 if (check_tsc_unstable()) {
-                        u64 offset = kvm_x86_ops->compute_tsc_offset(vcpu,
+                        u64 offset = kvm_compute_tsc_offset(vcpu,
                                                 vcpu->arch.last_guest_tsc);
                         kvm_x86_ops->write_tsc_offset(vcpu, offset);
                         vcpu->arch.tsc_catchup = 1;