[PATCH 04/12] KVM: x86: Replace call-back set_tsc_khz() with a common function

[Haozhong Zhang]

Both VMX and SVM propagate virtual_tsc_khz in the same way, so this
patch removes the call-back set_tsc_khz() and replaces it with a common
function.

Signed-off-by: Haozhong Zhang <haozhong.zhang@xxxxxxxxx>
---
 arch/x86/include/asm/kvm_host.h |  1 -
 arch/x86/kvm/svm.c              | 36 ------------------------------------
 arch/x86/kvm/vmx.c              | 17 -----------------
 arch/x86/kvm/x86.c              | 41 ++++++++++++++++++++++++++++++++++++++++-
 4 files changed, 40 insertions(+), 55 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 4f32c68..5a0c435 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -842,7 +842,6 @@ struct kvm_x86_ops {
 
 	bool (*has_wbinvd_exit)(void);
 
-	void (*set_tsc_khz)(struct kvm_vcpu *vcpu, u32 user_tsc_khz, bool scale);
 	u64 (*read_tsc_offset)(struct kvm_vcpu *vcpu);
 	void (*write_tsc_offset)(struct kvm_vcpu *vcpu, u64 offset);
 
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 1a333bd..d46dcf3 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -1015,41 +1015,6 @@ static void init_sys_seg(struct vmcb_seg *seg, uint32_t type)
 	seg->base = 0;
 }
 
-static void svm_set_tsc_khz(struct kvm_vcpu *vcpu, u32 user_tsc_khz, bool scale)
-{
-	u64 ratio;
-	u64 khz;
-
-	/* Guest TSC same frequency as host TSC? */
-	if (!scale) {
-		vcpu->arch.tsc_scaling_ratio = TSC_RATIO_DEFAULT;
-		return;
-	}
-
-	/* TSC scaling supported? */
-	if (!boot_cpu_has(X86_FEATURE_TSCRATEMSR)) {
-		if (user_tsc_khz > tsc_khz) {
-			vcpu->arch.tsc_catchup = 1;
-			vcpu->arch.tsc_always_catchup = 1;
-		} else
-			WARN(1, "user requested TSC rate below hardware speed\n");
-		return;
-	}
-
-	khz = user_tsc_khz;
-
-	/* TSC scaling required  - calculate ratio */
-	ratio = khz << 32;
-	do_div(ratio, tsc_khz);
-
-	if (ratio == 0 || ratio & TSC_RATIO_RSVD) {
-		WARN_ONCE(1, "Invalid TSC ratio - virtual-tsc-khz=%u\n",
-				user_tsc_khz);
-		return;
-	}
-	vcpu->arch.tsc_scaling_ratio = ratio;
-}
-
 static u64 svm_read_tsc_offset(struct kvm_vcpu *vcpu)
 {
 	struct vcpu_svm *svm = to_svm(vcpu);
@@ -4507,7 +4472,6 @@ static struct kvm_x86_ops svm_x86_ops = {
 
 	.has_wbinvd_exit = svm_has_wbinvd_exit,
 
-	.set_tsc_khz = svm_set_tsc_khz,
 	.read_tsc_offset = svm_read_tsc_offset,
 	.write_tsc_offset = svm_write_tsc_offset,
 	.adjust_tsc_offset = svm_adjust_tsc_offset,
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 6407674..1751537 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2255,22 +2255,6 @@ static u64 vmx_read_l1_tsc(struct kvm_vcpu *vcpu, u64 host_tsc)
 	return host_tsc + tsc_offset;
 }
 
-/*
- * Engage any workarounds for mis-matched TSC rates.  Currently limited to
- * software catchup for faster rates on slower CPUs.
- */
-static void vmx_set_tsc_khz(struct kvm_vcpu *vcpu, u32 user_tsc_khz, bool scale)
-{
-	if (!scale)
-		return;
-
-	if (user_tsc_khz > tsc_khz) {
-		vcpu->arch.tsc_catchup = 1;
-		vcpu->arch.tsc_always_catchup = 1;
-	} else
-		WARN(1, "user requested TSC rate below hardware speed\n");
-}
-
 static u64 vmx_read_tsc_offset(struct kvm_vcpu *vcpu)
 {
 	return vmcs_read64(TSC_OFFSET);
@@ -10380,7 +10364,6 @@ static struct kvm_x86_ops vmx_x86_ops = {
 
 	.has_wbinvd_exit = cpu_has_vmx_wbinvd_exit,
 
-	.set_tsc_khz = vmx_set_tsc_khz,
 	.read_tsc_offset = vmx_read_tsc_offset,
 	.write_tsc_offset = vmx_write_tsc_offset,
 	.adjust_tsc_offset = vmx_adjust_tsc_offset,
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 920c302..e2e1fdb 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1248,6 +1248,45 @@ static u32 adjust_tsc_khz(u32 khz, s32 ppm)
 	return v;
 }
 
+static void set_tsc_khz(struct kvm_vcpu *vcpu, u32 user_tsc_khz, bool scale)
+{
+	u64 ratio, khz;
+	s8 shift;
+
+	/* Guest TSC same frequency as host TSC? */
+	if (!scale) {
+		vcpu->arch.tsc_scaling_ratio = kvm_default_tsc_scaling_ratio;
+		return;
+	}
+
+	/* TSC scaling supported? */
+	if (!kvm_has_tsc_control) {
+		if (user_tsc_khz > tsc_khz) {
+			vcpu->arch.tsc_catchup = 1;
+			vcpu->arch.tsc_always_catchup = 1;
+		} else
+			WARN(1, "user requested TSC rate below hardware speed\n");
+		return;
+	}
+
+	khz = user_tsc_khz;
+
+	/* TSC scaling required  - calculate ratio */
+	shift = (kvm_tsc_scaling_ratio_frac_bits <= 32) ?
+		kvm_tsc_scaling_ratio_frac_bits : 32;
+	ratio = khz << shift;
+	do_div(ratio, tsc_khz);
+	ratio <<= (kvm_tsc_scaling_ratio_frac_bits - shift);
+
+	if (ratio == 0 || ratio & kvm_tsc_scaling_ratio_rsvd) {
+		WARN_ONCE(1, "Invalid TSC scaling ratio - virtual-tsc-khz=%u\n",
+			  user_tsc_khz);
+		return;
+	}
+
+	vcpu->arch.tsc_scaling_ratio = ratio;
+}
+
 static void kvm_set_tsc_khz(struct kvm_vcpu *vcpu, u32 this_tsc_khz)
 {
 	u32 thresh_lo, thresh_hi;
@@ -1275,7 +1314,7 @@ static void kvm_set_tsc_khz(struct kvm_vcpu *vcpu, u32 this_tsc_khz)
 		pr_debug("kvm: requested TSC rate %u falls outside tolerance [%u,%u]\n", this_tsc_khz, thresh_lo, thresh_hi);
 		use_scaling = 1;
 	}
-	kvm_x86_ops->set_tsc_khz(vcpu, this_tsc_khz, use_scaling);
+	set_tsc_khz(vcpu, this_tsc_khz, use_scaling);
 }
 
 static u64 compute_guest_tsc(struct kvm_vcpu *vcpu, s64 kernel_ns)
-- 
2.4.8

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