Re: [Xen-devel] [PATCH v2 01/18] x86/traps: factor out pv_percpu_traps_init

[Wei Liu <wei.liu2@xxxxxxxxxx>]

On Fri, May 05, 2017 at 05:12:25PM +0100, Andrew Cooper wrote:
> On 05/05/17 15:48, Wei Liu wrote:
> > The body of subarch_percpu_traps_init is for setting up PV syscall
> > trampoline. Move that into a dedicated function.
> >
> > Leave the BUILD_BUG_ON in the original function as it is not tied to PV.
> >
> > No functional change.
> >
> > Signed-off-by: Wei Liu <wei.liu2@xxxxxxxxxx>
> 
> The trampolines are only intended to be used by PV guests, but are still
> constitute parts of Xen setting up its entrypoints in a safe manor.
> 
> At the time I was adjusting the MSR_CSTAR handling, it was decided to
> retain it pointing at a safe location, even on hardware which shouldn't
> be able to use it.
> 
> Therefore, my plan was to keep the trampolines as general x86
> infrastructure, and have the (lifted into C) syscall entry points gain
> something like BUG_ON(!IS_DEFINED(CONFIG_PV))
> 

Fine by me. I will drop this patch in next version.

> ~Andrew

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
https://lists.xen.org/xen-devel