On 10/30/2012 11:23 AM, Avi Kivity wrote:
> On 10/24/2012 03:13 PM, Marcelo Tosatti wrote:
>> Originally from Jeremy Fitzhardinge.
>>
>> We can copy the information directly from "struct pvclock_vcpu_time_info",
>> remove pvclock_shadow_time.
>>
>> Signed-off-by: Marcelo Tosatti <mtosatti@xxxxxxxxxx>
>>
>>
>> unsigned long pvclock_tsc_khz(struct pvclock_vcpu_time_info *src)
>> @@ -90,21 +54,20 @@ void pvclock_resume(void)
>>
>> cycle_t pvclock_clocksource_read(struct pvclock_vcpu_time_info *src)
>> {
>> - struct pvclock_shadow_time shadow;
>> unsigned version;
>> cycle_t ret, offset;
>> u64 last;
>>
>> do {
>> - version = pvclock_get_time_values(&shadow, src);
>> + version = src->version;
>> rdtsc_barrier();
>> - offset = pvclock_get_nsec_offset(&shadow);
>> - ret = shadow.system_timestamp + offset;
>> + offset = pvclock_get_nsec_offset(src);
>> + ret = src->system_time + offset;
>> rdtsc_barrier();
>> - } while (version != src->version);
>> + } while ((src->version & 1) || version != src->version);
>>
>> if ((valid_flags & PVCLOCK_TSC_STABLE_BIT) &&
>> - (shadow.flags & PVCLOCK_TSC_STABLE_BIT))
>> + (src->flags & PVCLOCK_TSC_STABLE_BIT))
>> return ret;
>>
>
> You're now reading PVCLOCK_TSC_STABLE outside the critical section. We
> could have live migrated to a tsc-unstable host and had this flag cleared.
>
I see it's fixed in patch 5. So there's a window of two patches where
this is broken.
--
error compiling committee.c: too many arguments to function
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