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

[Julien Grall <julien.grall@xxxxxxx>]

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.
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?

Cheers,

--
Julien Grall

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