Xen devel - Jan 2008 - Question: xenoprof on HVM domU

Hi,

I played a little bit with the xenoprof interfaces on a PV domU and things 
work fine. But on a simple HVM domU these hypercalls failed with
"hvm.c:515:d1 HVM vcpu 1:0 did a bad hypercall 31."
I found that Xenoprof hypercallse are not supported in hvm_hypercall64_table.
Is there really a problem as it seems to me that the xenoprof stuff
shouldn''t
be that different on PV and HVM?
Many thanks.
Dietmar.

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Today the only hypercalls available to hvm guests are those needed to support PV
drivers.
The rational is that hvm is used to support unmodified OS which by definition do
not use hypercalls.  Exposing other hypercalls to hvm guests is a more general
issue and not xenoprof specific. Jun Nakajima from Intel has proposed a hybrid
virtualization model combinig hvm with paravirtualization
(http://xen.org/files/xensummit_4/XenLinux_Nakajima.pdf) by exposing additional
hyperacalls to hvm guests. When this model is accepted and supported into Xen we
can think of exposing xenoprof hypercall to hvm guests. For now you can profile
hvm guests using the passive domain model.

Regards

Renato
> -----Original Message-----
> From: xen-devel-bounces@lists.xensource.com
> [mailto:xen-devel-bounces@lists.xensource.com] On Behalf Of
> Dietmar Hahn
> Sent: Thursday, January 31, 2008 3:48 AM
> To: xen-devel
> Subject: [Xen-devel] Question: xenoprof on HVM domU
>
> Hi,
>
> I played a little bit with the xenoprof interfaces on a PV
> domU and things work fine. But on a simple HVM domU these
> hypercalls failed with
> "hvm.c:515:d1 HVM vcpu 1:0 did a bad hypercall 31."
> I found that Xenoprof hypercallse are not supported in
> hvm_hypercall64_table.
> Is there really a problem as it seems to me that the xenoprof
> stuff shouldn''t be that different on PV and HVM?
> Many thanks.
> Dietmar.
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel
>
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