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 | 46 ++++++++++++++++++++++++++++++++++++-----
include/linux/math64.h | 29 ++++++++++++++++++++++++++
5 files changed, 70 insertions(+), 59 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 1e08ad5..c67469b 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -853,7 +853,6 @@ 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 d347170..a1364927 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -958,41 +958,6 @@ 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);
@@ -4403,7 +4368,6 @@ 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 15bff51..7f87cf6 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2382,22 +2382,6 @@ 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);
@@ -10828,7 +10812,6 @@ 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 29c5781..db5ef73 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1252,7 +1252,43 @@ static u32 adjust_tsc_khz(u32 khz, s32 ppm)
return v;
}
-static void kvm_set_tsc_khz(struct kvm_vcpu *vcpu, u32 this_tsc_khz)
+static int set_tsc_khz(struct kvm_vcpu *vcpu, u32 user_tsc_khz, bool scale)
+{
+ u64 ratio;
+
+ /* Guest TSC same frequency as host TSC? */
+ if (!scale) {
+ vcpu->arch.tsc_scaling_ratio = kvm_default_tsc_scaling_ratio;
+ return 0;
+ }
+
+ /* 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;
+ return 0;
+ } else {
+ WARN(1, "user requested TSC rate below hardware speed\n");
+ return -1;
+ }
+ }
+
+ /* TSC scaling required - calculate ratio */
+ ratio = mul_u64_u32_div(1ULL << kvm_tsc_scaling_ratio_frac_bits,
+ user_tsc_khz, tsc_khz);
+
+ if (ratio == 0 || ratio >= kvm_max_tsc_scaling_ratio) {
+ WARN_ONCE(1, "Invalid TSC scaling ratio - virtual-tsc-khz=%u\n",
+ user_tsc_khz);
+ return -1;
+ }
+
+ vcpu->arch.tsc_scaling_ratio = ratio;
+ return 0;
+}
+
+static int kvm_set_tsc_khz(struct kvm_vcpu *vcpu, u32 this_tsc_khz)
{
u32 thresh_lo, thresh_hi;
int use_scaling = 0;
@@ -1261,7 +1297,7 @@ static void kvm_set_tsc_khz(struct kvm_vcpu *vcpu, u32 this_tsc_khz)
if (this_tsc_khz == 0) {
/* set tsc_scaling_ratio to a safe value */
vcpu->arch.tsc_scaling_ratio = kvm_default_tsc_scaling_ratio;
- return;
+ return -1;
}
/* Compute a scale to convert nanoseconds in TSC cycles */
@@ -1282,7 +1318,7 @@ 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);
+ return set_tsc_khz(vcpu, this_tsc_khz, use_scaling);
}
static u64 compute_guest_tsc(struct kvm_vcpu *vcpu, s64 kernel_ns)
@@ -3358,9 +3394,9 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
if (user_tsc_khz == 0)
user_tsc_khz = tsc_khz;
- kvm_set_tsc_khz(vcpu, user_tsc_khz);
+ if (!kvm_set_tsc_khz(vcpu, user_tsc_khz))
+ r = 0;
- r = 0;
goto out;
}
case KVM_GET_TSC_KHZ: {
diff --git a/include/linux/math64.h b/include/linux/math64.h
index 78aa80b..df2279c 100644
--- a/include/linux/math64.h
+++ b/include/linux/math64.h
@@ -233,4 +233,33 @@ static inline u64 mul_u64_u64_shr(u64 a, u64 mul, unsigned int shift)
#endif
+#ifndef mul_u64_u32_div
+static inline u64 mul_u64_u32_div(u64 a, u32 mul, u32 divisor)
+{
+ union {
+ u64 ll;
+ struct {
+#ifdef __BIG_ENDIAN
+ u32 high, low;
+#else
+ u32 low, high;
+#endif
+ } l;
+ } u, rl, rh;
+
+ u.ll = a;
+ rl.ll = (u64)u.l.low * mul;
+ rh.ll = (u64)u.l.high * mul + rl.l.high;
+
+ /* Bits 32-63 of the result will be in rh.l.low. */
+ rl.l.high = do_div(rh.ll, divisor);
+
+ /* Bits 0-31 of the result will be in rl.l.low. */
+ do_div(rl.ll, divisor);
+
+ rl.l.high = rh.l.low;
+ return rl.ll;
+}
+#endif /* mul_u64_u32_div */
+
#endif /* _LINUX_MATH64_H */
--
2.4.8
--
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