On 12/30/2015 10:03 PM, Haozhong Zhang wrote:
When the TSC mode of a HVM container is TSC_MODE_DEFAULT or
TSC_MODE_PVRDTSCP and no TSC emulation is used, the existing
tsc_get_info() uses the host TSC frequency (cpu_khz) as the guest TSC
frequency. However, tsc_set_info() may set the guest TSC frequency to a
value different than the host. In order to keep consistent to
tsc_set_info(), this patch makes tsc_get_info() use the value set by
tsc_set_info() as the guest TSC frequency.
Signed-off-by: Haozhong Zhang <haozhong.zh...@intel.com>
---
Changes in v3:
(addressing Boris Ostrovsky's comments)
* Use this_cpu(cpu_time).tsc_scale for both scaling and non-scaling cases.
xen/arch/x86/time.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/xen/arch/x86/time.c b/xen/arch/x86/time.c
index 0059b6a..d83f068 100644
--- a/xen/arch/x86/time.c
+++ b/xen/arch/x86/time.c
@@ -1749,6 +1749,9 @@ void tsc_get_info(struct domain *d, uint32_t *tsc_mode,
uint64_t *elapsed_nsec, uint32_t *gtsc_khz,
uint32_t *incarnation)
{
+ bool_t enable_tsc_scaling = has_hvm_container_domain(d) &&
+ cpu_has_tsc_ratio;
+
Reviewed-by: Boris Ostrovsky <boris.ostrov...@oracle.com>
although I still think that having !d->arch.vtsc would be better, even
if not strictly required.
*incarnation = d->arch.incarnation;
*tsc_mode = d->arch.tsc_mode;
@@ -1769,7 +1772,7 @@ void tsc_get_info(struct domain *d, uint32_t *tsc_mode,
}
tsc = rdtsc();
*elapsed_nsec = scale_delta(tsc, &d->arch.vtsc_to_ns);
- *gtsc_khz = cpu_khz;
+ *gtsc_khz = enable_tsc_scaling ? d->arch.tsc_khz : cpu_khz;
break;
case TSC_MODE_PVRDTSCP:
if ( d->arch.vtsc )
@@ -1780,9 +1783,9 @@ void tsc_get_info(struct domain *d, uint32_t *tsc_mode,
else
{
tsc = rdtsc();
- *elapsed_nsec = scale_delta(tsc, &d->arch.vtsc_to_ns) -
+ *elapsed_nsec = scale_delta(tsc, &this_cpu(cpu_time).tsc_scale) -
d->arch.vtsc_offset;
- *gtsc_khz = 0; /* ignored by tsc_set_info */
+ *gtsc_khz = enable_tsc_scaling ? d->arch.tsc_khz : 0;
}
break;
}
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