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

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@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 52d1419968ebd2fb20356f9754e6dcb4722ff072..c5a3f3d66e905cf38cdaa744d6c4f04acceeb368 100644 (file)
--- 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 65f4f1947a62c060b4c2a8048c3da0ab811efa75..f6e49a6c9ab0f76da2ac71453e35113d3885da32 100644 (file)
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -957,41 +957,6 @@ 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);
@@ -4402,7 +4367,6 @@ 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 a26ed285931bc746151985673abfc0b061f15259..baee468938997656c0194f19c41019ccfc67771b 100644 (file)
--- 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);
@@ -10826,7 +10810,6 @@ 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 1473e64cb744c7ae5a88956bb89bc9d5fabe87b2..c314e8d22a671f80e8f2323137478eb507101d00 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1253,7 +1253,43 @@ 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;
@@ -1262,7 +1298,7 @@ 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 */
@@ -1283,7 +1319,7 @@ 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)
@@ -3353,9 +3389,9 @@ 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 44282ec7b682cf9e5db36b6ed5a380fa6ee87d25..6e8b5b270ffeada870b3cdcd638530f2479b84ee 100644 (file)
--- a/include/linux/math64.h
+++ b/include/linux/math64.h
@@ -214,4 +214,33 @@ static inline u64 mul_u64_u64_shr(u64 a, u64 b, 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 */