Re: [Xen-devel] [PATCH] tools/libxl: Fix build following c/s 74fd984ae

[Wei Liu <wei.liu2@xxxxxxxxxx>]

On Mon, Apr 09, 2018 at 11:29:28AM +0100, Julien Grall wrote:
> Hi,
> 
> On 06/04/18 10:33, Wei Liu wrote:
> > On Fri, Apr 06, 2018 at 10:03:14AM +0100, Julien Grall wrote:
> > > This is wrong. gicv_to_string works on XEN_DOMCTL_* define and not the 
> > > LIBXL_GIC_*.
> > > So this will not give the right output.
> > > 
> > > I would suggest to revert that patch and I will send one that actually 
> > > fix the compilation.
> > > Not sure I would be able to do it today thought.
> > > 
> > 
> > OK, I will revert this patch.
> 
> I have looked at a potential way to fix it. The original patch (74fd984ae6)
> assumption is incorrect. Some of information from xc_domain_configuration_t
> is not written back ton libxl__domain_build_state.
> 
> For instance, this is the case of the clock frequency. That field is used to
> workaround bootloader/firmware that didn't configure correct CNTFRQ. If we
> detect such platform, we will read the host clock frequency from the host
> Device-Tree and write it to the guest Device-Tree. This should never be
> exposed to the guest.

Not sure I follow. If you write that value to guest DT, guest should be
able to see it?

> 
> Arguably, this field should not belong to xc_domain_configuration_t. So I
> can see two solutions:
>       1) Store the frequency in libxl__domain_build_state
>       2) Introduce a different hypercall to get the system frequency. I guess 
> we
> could piggy-back on Andrew's idea to provide
> XEN_DOMCTL_{get,set}_arch_settings.
> 
> The latter will require some rework in the code and define a new API. Not
> sure if that would be acceptable for Xen 4.11.
> 
> Any opinions?

#1 seems simpler to me, especially since we already have vuart (ARM
only) information in libxl__domain_build_state.

Wei.

> 
> Cheers,
> 
> -- 
> Julien Grall

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel