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-rw-r--r--arch/x86/include/asm/kvm_host.h2
-rw-r--r--arch/x86/kvm/svm.c48
-rw-r--r--arch/x86/kvm/x86.c40
-rw-r--r--include/linux/kvm_host.h1
-rw-r--r--include/linux/math64.h51
5 files changed, 97 insertions, 45 deletions
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index f3354bd92364..52d1419968eb 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1238,6 +1238,8 @@ void kvm_arch_mmu_notifier_invalidate_page(struct kvm *kvm,
void kvm_define_shared_msr(unsigned index, u32 msr);
int kvm_set_shared_msr(unsigned index, u64 val, u64 mask);
+u64 kvm_scale_tsc(struct kvm_vcpu *vcpu, u64 tsc);
+
unsigned long kvm_get_linear_rip(struct kvm_vcpu *vcpu);
bool kvm_is_linear_rip(struct kvm_vcpu *vcpu, unsigned long linear_rip);
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 9c92e6f429d0..65f4f1947a62 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -212,7 +212,6 @@ static int nested_svm_intercept(struct vcpu_svm *svm);
static int nested_svm_vmexit(struct vcpu_svm *svm);
static int nested_svm_check_exception(struct vcpu_svm *svm, unsigned nr,
bool has_error_code, u32 error_code);
-static u64 __scale_tsc(u64 ratio, u64 tsc);
enum {
VMCB_INTERCEPTS, /* Intercept vectors, TSC offset,
@@ -892,21 +891,7 @@ static __init int svm_hardware_setup(void)
kvm_enable_efer_bits(EFER_FFXSR);
if (boot_cpu_has(X86_FEATURE_TSCRATEMSR)) {
- u64 max;
-
kvm_has_tsc_control = true;
-
- /*
- * Make sure the user can only configure tsc_khz values that
- * fit into a signed integer.
- * A min value is not calculated needed because it will always
- * be 1 on all machines and a value of 0 is used to disable
- * tsc-scaling for the vcpu.
- */
- max = min(0x7fffffffULL, __scale_tsc(tsc_khz, TSC_RATIO_MAX));
-
- kvm_max_guest_tsc_khz = max;
-
kvm_max_tsc_scaling_ratio = TSC_RATIO_MAX;
kvm_tsc_scaling_ratio_frac_bits = 32;
}
@@ -972,31 +957,6 @@ static void init_sys_seg(struct vmcb_seg *seg, uint32_t type)
seg->base = 0;
}
-static u64 __scale_tsc(u64 ratio, u64 tsc)
-{
- u64 mult, frac, _tsc;
-
- mult = ratio >> 32;
- frac = ratio & ((1ULL << 32) - 1);
-
- _tsc = tsc;
- _tsc *= mult;
- _tsc += (tsc >> 32) * frac;
- _tsc += ((tsc & ((1ULL << 32) - 1)) * frac) >> 32;
-
- return _tsc;
-}
-
-static u64 svm_scale_tsc(struct kvm_vcpu *vcpu, u64 tsc)
-{
- u64 _tsc = tsc;
-
- if (vcpu->arch.tsc_scaling_ratio != TSC_RATIO_DEFAULT)
- _tsc = __scale_tsc(vcpu->arch.tsc_scaling_ratio, tsc);
-
- return _tsc;
-}
-
static void svm_set_tsc_khz(struct kvm_vcpu *vcpu, u32 user_tsc_khz, bool scale)
{
u64 ratio;
@@ -1065,7 +1025,7 @@ static void svm_adjust_tsc_offset(struct kvm_vcpu *vcpu, s64 adjustment, bool ho
if (host) {
if (vcpu->arch.tsc_scaling_ratio != TSC_RATIO_DEFAULT)
WARN_ON(adjustment < 0);
- adjustment = svm_scale_tsc(vcpu, (u64)adjustment);
+ adjustment = kvm_scale_tsc(vcpu, (u64)adjustment);
}
svm->vmcb->control.tsc_offset += adjustment;
@@ -1083,7 +1043,7 @@ static u64 svm_compute_tsc_offset(struct kvm_vcpu *vcpu, u64 target_tsc)
{
u64 tsc;
- tsc = svm_scale_tsc(vcpu, rdtsc());
+ tsc = kvm_scale_tsc(vcpu, rdtsc());
return target_tsc - tsc;
}
@@ -3075,7 +3035,7 @@ static u64 svm_read_l1_tsc(struct kvm_vcpu *vcpu, u64 host_tsc)
{
struct vmcb *vmcb = get_host_vmcb(to_svm(vcpu));
return vmcb->control.tsc_offset +
- svm_scale_tsc(vcpu, host_tsc);
+ kvm_scale_tsc(vcpu, host_tsc);
}
static int svm_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
@@ -3085,7 +3045,7 @@ static int svm_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
switch (msr_info->index) {
case MSR_IA32_TSC: {
msr_info->data = svm->vmcb->control.tsc_offset +
- svm_scale_tsc(vcpu, rdtsc());
+ kvm_scale_tsc(vcpu, rdtsc());
break;
}
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index ef5b9d66cd71..1473e64cb744 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1329,6 +1329,33 @@ static void update_ia32_tsc_adjust_msr(struct kvm_vcpu *vcpu, s64 offset)
vcpu->arch.ia32_tsc_adjust_msr += offset - curr_offset;
}
+/*
+ * Multiply tsc by a fixed point number represented by ratio.
+ *
+ * The most significant 64-N bits (mult) of ratio represent the
+ * integral part of the fixed point number; the remaining N bits
+ * (frac) represent the fractional part, ie. ratio represents a fixed
+ * point number (mult + frac * 2^(-N)).
+ *
+ * N equals to kvm_tsc_scaling_ratio_frac_bits.
+ */
+static inline u64 __scale_tsc(u64 ratio, u64 tsc)
+{
+ return mul_u64_u64_shr(tsc, ratio, kvm_tsc_scaling_ratio_frac_bits);
+}
+
+u64 kvm_scale_tsc(struct kvm_vcpu *vcpu, u64 tsc)
+{
+ u64 _tsc = tsc;
+ u64 ratio = vcpu->arch.tsc_scaling_ratio;
+
+ if (ratio != kvm_default_tsc_scaling_ratio)
+ _tsc = __scale_tsc(ratio, tsc);
+
+ return _tsc;
+}
+EXPORT_SYMBOL_GPL(kvm_scale_tsc);
+
void kvm_write_tsc(struct kvm_vcpu *vcpu, struct msr_data *msr)
{
struct kvm *kvm = vcpu->kvm;
@@ -7371,8 +7398,19 @@ int kvm_arch_hardware_setup(void)
if (r != 0)
return r;
- if (kvm_has_tsc_control)
+ if (kvm_has_tsc_control) {
+ /*
+ * Make sure the user can only configure tsc_khz values that
+ * fit into a signed integer.
+ * A min value is not calculated needed because it will always
+ * be 1 on all machines.
+ */
+ u64 max = min(0x7fffffffULL,
+ __scale_tsc(kvm_max_tsc_scaling_ratio, tsc_khz));
+ kvm_max_guest_tsc_khz = max;
+
kvm_default_tsc_scaling_ratio = 1ULL << kvm_tsc_scaling_ratio_frac_bits;
+ }
kvm_init_msr_list();
return 0;
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 242a6d2b53ff..5706a2108f0a 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1183,4 +1183,5 @@ void kvm_arch_irq_bypass_start(struct irq_bypass_consumer *);
int kvm_arch_update_irqfd_routing(struct kvm *kvm, unsigned int host_irq,
uint32_t guest_irq, bool set);
#endif /* CONFIG_HAVE_KVM_IRQ_BYPASS */
+
#endif
diff --git a/include/linux/math64.h b/include/linux/math64.h
index c45c089bfdac..44282ec7b682 100644
--- a/include/linux/math64.h
+++ b/include/linux/math64.h
@@ -142,6 +142,13 @@ static inline u64 mul_u64_u32_shr(u64 a, u32 mul, unsigned int shift)
}
#endif /* mul_u64_u32_shr */
+#ifndef mul_u64_u64_shr
+static inline u64 mul_u64_u64_shr(u64 a, u64 mul, unsigned int shift)
+{
+ return (u64)(((unsigned __int128)a * mul) >> shift);
+}
+#endif /* mul_u64_u64_shr */
+
#else
#ifndef mul_u64_u32_shr
@@ -161,6 +168,50 @@ static inline u64 mul_u64_u32_shr(u64 a, u32 mul, unsigned int shift)
}
#endif /* mul_u64_u32_shr */
+#ifndef mul_u64_u64_shr
+static inline u64 mul_u64_u64_shr(u64 a, u64 b, unsigned int shift)
+{
+ union {
+ u64 ll;
+ struct {
+#ifdef __BIG_ENDIAN
+ u32 high, low;
+#else
+ u32 low, high;
+#endif
+ } l;
+ } rl, rm, rn, rh, a0, b0;
+ u64 c;
+
+ a0.ll = a;
+ b0.ll = b;
+
+ rl.ll = (u64)a0.l.low * b0.l.low;
+ rm.ll = (u64)a0.l.low * b0.l.high;
+ rn.ll = (u64)a0.l.high * b0.l.low;
+ rh.ll = (u64)a0.l.high * b0.l.high;
+
+ /*
+ * Each of these lines computes a 64-bit intermediate result into "c",
+ * starting at bits 32-95. The low 32-bits go into the result of the
+ * multiplication, the high 32-bits are carried into the next step.
+ */
+ rl.l.high = c = (u64)rl.l.high + rm.l.low + rn.l.low;
+ rh.l.low = c = (c >> 32) + rm.l.high + rn.l.high + rh.l.low;
+ rh.l.high = (c >> 32) + rh.l.high;
+
+ /*
+ * The 128-bit result of the multiplication is in rl.ll and rh.ll,
+ * shift it right and throw away the high part of the result.
+ */
+ if (shift == 0)
+ return rl.ll;
+ if (shift < 64)
+ return (rl.ll >> shift) | (rh.ll << (64 - shift));
+ return rh.ll >> (shift & 63);
+}
+#endif /* mul_u64_u64_shr */
+
#endif
#endif /* _LINUX_MATH64_H */