[Xen-devel] [PATCH v4 07/10] x86/hvm: Replace architecture TSC scaling by a common function

[Haozhong Zhang <haozhong.zhang@xxxxxxxxx>]

This patch implements a common function hvm_scale_tsc() to scale TSC by
using TSC scaling information collected by architecture code.

Signed-off-by: Haozhong Zhang <haozhong.zhang@xxxxxxxxx>
Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx> (except the mul64 part)
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
Acked-by: Jan Beulich <jbeulich@xxxxxxxx>
---
 xen/arch/x86/hvm/hvm.c        | 14 ++++++++++++--
 xen/arch/x86/hvm/svm/svm.c    |  8 --------
 xen/arch/x86/time.c           |  2 +-
 xen/include/asm-x86/hvm/hvm.h |  4 +---
 4 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index 64a7760..8549dab 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -302,6 +302,16 @@ int hvm_set_guest_pat(struct vcpu *v, u64 guest_pat)
     return 1;
 }
 
+u64 hvm_scale_tsc(const struct vcpu *v, u64 tsc)
+{
+    u64 ratio = v->arch.hvm_vcpu.tsc_scaling_ratio;
+
+    if ( ratio == hvm_funcs.default_tsc_scaling_ratio )
+        return tsc;
+
+    return mul_u64_u64_shr(tsc, ratio, hvm_funcs.tsc_scaling_ratio_frac_bits);
+}
+
 /*
  * Get the ratio to scale host TSC frequency to gtsc_khz. zero will be
  * returned if TSC scaling is unavailable or ratio cannot be handled
@@ -344,7 +354,7 @@ void hvm_set_guest_tsc_fixed(struct vcpu *v, u64 guest_tsc, 
u64 at_tsc)
     {
         tsc = at_tsc ?: rdtsc();
         if ( hvm_tsc_scaling_supported )
-            tsc = hvm_funcs.scale_tsc(v, tsc);
+            tsc = hvm_scale_tsc(v, tsc);
     }
 
     delta_tsc = guest_tsc - tsc;
@@ -376,7 +386,7 @@ u64 hvm_get_guest_tsc_fixed(struct vcpu *v, uint64_t at_tsc)
     {
         tsc = at_tsc ?: rdtsc();
         if ( hvm_tsc_scaling_supported )
-            tsc = hvm_funcs.scale_tsc(v, tsc);
+            tsc = hvm_scale_tsc(v, tsc);
     }
 
     return tsc + v->arch.hvm_vcpu.cache_tsc_offset;
diff --git a/xen/arch/x86/hvm/svm/svm.c b/xen/arch/x86/hvm/svm/svm.c
index 17bce5c..a4ac38c 100644
--- a/xen/arch/x86/hvm/svm/svm.c
+++ b/xen/arch/x86/hvm/svm/svm.c
@@ -804,13 +804,6 @@ static uint64_t scale_tsc(uint64_t host_tsc, uint64_t 
ratio)
     return scaled_host_tsc;
 }
 
-static uint64_t svm_scale_tsc(const struct vcpu *v, uint64_t tsc)
-{
-    ASSERT(cpu_has_tsc_ratio && !v->domain->arch.vtsc);
-
-    return scale_tsc(tsc, v->arch.hvm_vcpu.tsc_scaling_ratio);
-}
-
 static uint64_t svm_get_tsc_offset(uint64_t host_tsc, uint64_t guest_tsc,
     uint64_t ratio)
 {
@@ -1457,7 +1450,6 @@ const struct hvm_function_table * __init start_svm(void)
         svm_function_table.default_tsc_scaling_ratio = DEFAULT_TSC_RATIO;
         svm_function_table.max_tsc_scaling_ratio = ~TSC_RATIO_RSVD_BITS;
         svm_function_table.tsc_scaling_ratio_frac_bits = 32;
-        svm_function_table.scale_tsc = svm_scale_tsc;
     }
 
 #define P(p,s) if ( p ) { printk(" - %s\n", s); printed = 1; }
diff --git a/xen/arch/x86/time.c b/xen/arch/x86/time.c
index 2ce6447..b4a6708 100644
--- a/xen/arch/x86/time.c
+++ b/xen/arch/x86/time.c
@@ -816,7 +816,7 @@ static void __update_vcpu_system_time(struct vcpu *v, int 
force)
     {
         if ( has_hvm_container_domain(d) && hvm_tsc_scaling_supported )
         {
-            tsc_stamp            = hvm_funcs.scale_tsc(v, t->local_tsc_stamp);
+            tsc_stamp            = hvm_scale_tsc(v, t->local_tsc_stamp);
             _u.tsc_to_system_mul = d->arch.vtsc_to_ns.mul_frac;
             _u.tsc_shift         = d->arch.vtsc_to_ns.shift;
         }
diff --git a/xen/include/asm-x86/hvm/hvm.h b/xen/include/asm-x86/hvm/hvm.h
index f2d1419..5588b92 100644
--- a/xen/include/asm-x86/hvm/hvm.h
+++ b/xen/include/asm-x86/hvm/hvm.h
@@ -223,9 +223,6 @@ struct hvm_function_table {
     void (*altp2m_vcpu_update_vmfunc_ve)(struct vcpu *v);
     bool_t (*altp2m_vcpu_emulate_ve)(struct vcpu *v);
     int (*altp2m_vcpu_emulate_vmfunc)(struct cpu_user_regs *regs);
-
-    /* Valid only when hardware-assisted TSC scaling is available */
-    uint64_t (*scale_tsc)(const struct vcpu *v, uint64_t tsc);
 };
 
 extern struct hvm_function_table hvm_funcs;
@@ -263,6 +260,7 @@ u64 hvm_get_guest_tsc_fixed(struct vcpu *v, u64 at_tsc);
 
 #define hvm_tsc_scaling_supported (!!hvm_funcs.default_tsc_scaling_ratio)
 
+u64 hvm_scale_tsc(const struct vcpu *v, u64 tsc);
 u64 hvm_get_tsc_scaling_ratio(u32 gtsc_khz);
 void hvm_setup_tsc_scaling(struct vcpu *v);
 
-- 
2.7.0


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