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.zh...@intel.com>
---
Changes in v5:
* Drop "Reviewed-by" from Kevin Tian and Boris Ostrovsky and "Acked-by"
from Jan Beulich because of following changes.
* Rewrite 64-bit integer arithmetic in hvm_scale_tsc() by inlined assembly.
* Change the first argument of hvm_scale_tsc() from 'const struct vcpu *'
to 'const struct domain *' because it does not relied on vcpu.
---
xen/arch/x86/hvm/hvm.c | 21 +++++++++++++++++++--
xen/arch/x86/hvm/svm/svm.c | 8 --------
xen/arch/x86/time.c | 3 +--
xen/include/asm-x86/hvm/hvm.h | 3 +--
4 files changed, 21 insertions(+), 14 deletions(-)
diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index b239bdb..c6a6198 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -321,6 +321,23 @@ u64 hvm_get_tsc_scaling_ratio(u32 gtsc_khz)
return ratio > hvm_funcs.tsc_scaling.max_ratio ? 0 : ratio;
}
+u64 hvm_scale_tsc(const struct domain *d, u64 tsc)
+{
+ u64 ratio = d->arch.hvm_domain.tsc_scaling_ratio;
+ u64 dummy;
+
+ if ( ratio == hvm_default_tsc_scaling_ratio )
+ return tsc;
+
+ /* tsc = (tsc * ratio) >> hvm_funcs.tsc_scaling.ratio_frac_bits */
+ asm (
+ "mulq %3; shrdq %2,%1,%0"
+ : "+a" (tsc), "=d" (dummy)
+ : "c" (hvm_funcs.tsc_scaling.ratio_frac_bits), "rm" (ratio) );
+
+ return tsc;
+}
+
void hvm_set_guest_tsc_fixed(struct vcpu *v, u64 guest_tsc, u64 at_tsc)
{
uint64_t tsc;
@@ -335,7 +352,7 @@ 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.tsc_scaling.scale_tsc(v, tsc);
+ tsc = hvm_scale_tsc(v->domain, tsc);
}
delta_tsc = guest_tsc - tsc;
@@ -367,7 +384,7 @@ 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.tsc_scaling.scale_tsc(v, tsc);
+ tsc = hvm_scale_tsc(v->domain, 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 1136937..dbdfc5b 100644
--- a/xen/arch/x86/hvm/svm/svm.c
+++ b/xen/arch/x86/hvm/svm/svm.c
@@ -819,13 +819,6 @@ 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, hvm_vcpu_tsc_scaling_ratio(v));
-}
-
static uint64_t svm_get_tsc_offset(uint64_t host_tsc, uint64_t guest_tsc,
uint64_t ratio)
{
@@ -2291,7 +2284,6 @@ static struct hvm_function_table __initdata
svm_function_table = {
.tsc_scaling = {
.max_ratio = ~TSC_RATIO_RSVD_BITS,
- .scale_tsc = svm_scale_tsc,
},
};
diff --git a/xen/arch/x86/time.c b/xen/arch/x86/time.c
index fda9692..687e39b 100644
--- a/xen/arch/x86/time.c
+++ b/xen/arch/x86/time.c
@@ -816,8 +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.tsc_scaling.scale_tsc(v, t->local_tsc_stamp);
+ tsc_stamp = hvm_scale_tsc(d, 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 6264d9e..fc9616a 100644
--- a/xen/include/asm-x86/hvm/hvm.h
+++ b/xen/include/asm-x86/hvm/hvm.h
@@ -231,8 +231,6 @@ struct hvm_function_table {
uint8_t ratio_frac_bits;
/* maximum-allowed TSC scaling ratio */
uint64_t max_ratio;
-
- uint64_t (*scale_tsc)(const struct vcpu *v, uint64_t tsc);
} tsc_scaling;
};
@@ -278,6 +276,7 @@ u64 hvm_get_guest_tsc_fixed(struct vcpu *v, u64 at_tsc);
#define hvm_vcpu_tsc_scaling_ratio(v) \
((v)->domain->arch.hvm_domain.tsc_scaling_ratio)
+u64 hvm_scale_tsc(const struct domain *d, u64 tsc);
u64 hvm_get_tsc_scaling_ratio(u32 gtsc_khz);
int hvm_set_mode(struct vcpu *v, int mode);
--
2.7.1
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