RE: [Xen-devel][PATCH 01/02] pvrdtscp: move the place of write_rdtscp_aux()

[Dan Magenheimer <dan.magenheimer@xxxxxxxxxx>]

This patch is wrong for TSC_MODE_PVRDTSCP.  The original
code should be left in __update_vcpu_system_time and
the context switch code should write to TSC_AUX only
if tsc_mode is *NOT* TSC_MODE_PVRDTSCP because the
implementation of full rdtscp functionality and
TSC_MODE_PVRDTSCP mode are incompatible.

But I continue to question if this should be done at all.
See other thread.

> -----Original Message-----
> From: Xu, Dongxiao [mailto:dongxiao.xu@xxxxxxxxx]
> Sent: Friday, December 11, 2009 4:54 AM
> To: xen-devel@xxxxxxxxxxxxxxxxxxx
> Cc: Keir Fraser
> Subject: [Xen-devel][PATCH 01/02] pvrdtscp: move the place of
> write_rdtscp_aux()
> 
> 
>  Pvrdtscp: move write_rdtscp_aux() to paravirt_ctxt_switch_to()
>  - Currently write_rdtscp_aux() is placed in 
> update_vcpu_system_time(), which
> is called by schedule() before context_switch(). This will 
> break the HVM guest
> TSC_AUX state because at this point, MSR hasn't beed saved 
> for HVM guests.So
> put the function in the point when a PV vcpu is really scheduled in. 
> 
> Signed-off-by: Dongxiao Xu <dongxiao.xu@xxxxxxxxx>

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