On 12/06/2015 03:58 PM, Haozhong Zhang wrote:
When TSC_MODE_PVRDTSCP is used for a HVM container and TSC scaling is
available, use the non-zero value of argument gtsc_khz of tsc_set_info()
as the guest TSC frequency rather than using the host TSC
frequency. Otherwise, TSC scaling will not be able get the correct ratio
between the host and guest TSC frequencies.
Signed-off-by: Haozhong Zhang <haozhong.zh...@intel.com>
---
xen/arch/x86/time.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/xen/arch/x86/time.c b/xen/arch/x86/time.c
index b5223cf..1091e69 100644
--- a/xen/arch/x86/time.c
+++ b/xen/arch/x86/time.c
@@ -1803,6 +1803,8 @@ void tsc_set_info(struct domain *d,
uint32_t tsc_mode, uint64_t elapsed_nsec,
uint32_t gtsc_khz, uint32_t incarnation)
{
+ bool_t enable_tsc_scaling;
+
if ( is_idle_domain(d) || is_hardware_domain(d) )
{
d->arch.vtsc = 0;
@@ -1864,7 +1866,9 @@ void tsc_set_info(struct domain *d,
case TSC_MODE_PVRDTSCP:
d->arch.vtsc = !boot_cpu_has(X86_FEATURE_RDTSCP) ||
!host_tsc_is_safe();
- d->arch.tsc_khz = cpu_khz;
+ enable_tsc_scaling = has_hvm_container_domain(d) &&
+ cpu_has_tsc_ratio && d->arch.vtsc;
+ d->arch.tsc_khz = (enable_tsc_scaling && gtsc_khz) ? gtsc_khz :
cpu_khz;
set_time_scale(&d->arch.vtsc_to_ns, d->arch.tsc_khz * 1000 );
d->arch.ns_to_vtsc = scale_reciprocal(d->arch.vtsc_to_ns);
if ( d->arch.vtsc )
@@ -1872,7 +1876,10 @@ void tsc_set_info(struct domain *d,
else {
/* when using native TSC, offset is nsec relative to power-on
* of physical machine */
- d->arch.vtsc_offset = scale_delta(rdtsc(), &d->arch.vtsc_to_ns) -
+ struct time_scale *scale = enable_tsc_scaling ?
Do we need this test here? Per previous chunk, enable_tsc_scaling will
be zero since d->arch.vtsc is false.
Actually, if you are trying to use (or, rather, account for) TSC
scaling, shouldn't it be !arch.vtsc there?
-boris
+ &this_cpu(cpu_time).tsc_scale :
+ &d->arch.vtsc_to_ns;
+ d->arch.vtsc_offset = scale_delta(rdtsc(), scale) -
elapsed_nsec;
}
break;
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