Re: [PATCH 09/13] x86/time.c: Scale host TSC in pvclock properly

[Haozhong Zhang <haozhong.zhang@intel.com>]

On Mon, Sep 28, 2015 at 12:36:51PM -0400, Boris Ostrovsky wrote:
> On 09/28/2015 03:13 AM, Haozhong Zhang wrote:
> >This patch makes the pvclock return the scaled host TSC and
> >corresponding scaling parameters to HVM domains if guest TSC is not
> >emulated and TSC scaling is enabled.
> >
> >Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>
> >---
> >  xen/arch/x86/time.c | 15 ++++++++++++---
> >  1 file changed, 12 insertions(+), 3 deletions(-)
> >
> >diff --git a/xen/arch/x86/time.c b/xen/arch/x86/time.c
> >index 4b5402c..54eab6e 100644
> >--- a/xen/arch/x86/time.c
> >+++ b/xen/arch/x86/time.c
> >@@ -832,10 +832,19 @@ static void __update_vcpu_system_time(struct vcpu *v, int force)
> >      }
> >      else
> >      {
> >-        _u.tsc_timestamp     = t->local_tsc_stamp;
> >+        if ( is_hvm_domain(d) && hvm_funcs.tsc_scaling_supported )
> 
> This should probably be has_hvm_container_domain(d).
> 
> And I think you also may need to adjust this in patch 4 (tsc_set_info()).
>

Yes, I'll change them to has_hvm_container_domain() in next version.

> -boris
> 
> 
> >+        {
> >+            _u.tsc_timestamp     = 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;
> >+        }
> >+        else
> >+        {
> >+            _u.tsc_timestamp     = t->local_tsc_stamp;
> >+            _u.tsc_to_system_mul = t->tsc_scale.mul_frac;
> >+            _u.tsc_shift         = (s8)t->tsc_scale.shift;
> >+        }
> >          _u.system_time       = t->stime_local_stamp;
> >-        _u.tsc_to_system_mul = t->tsc_scale.mul_frac;
> >-        _u.tsc_shift         = (s8)t->tsc_scale.shift;
> >      }
> >      if ( is_hvm_domain(d) )
> >          _u.tsc_timestamp += v->arch.hvm_vcpu.cache_tsc_offset;
> 
- Haozhong Zhang