Re: [Xen-devel] [PATCH 08/17 v5] xen/arm: vpl011: Add a new domctl API to initialize vpl011

[Julien Grall <julien.grall@xxxxxxx>]

On 27/06/17 14:43, Bhupinder Thakur wrote:
> Hi Julien,
Hi Bhupinder,

> > > > > +#if defined (__arm__) || defined(__aarch64__)
> > > > > +/**
> > > > > + * This function initializes the vpl011 emulation and returns
> > > > > + * the event to be used by the backend for communicating with
> > > > > + * the emulation code.
> > > > > + *
> > > > > + * @parm xch a handle to an open hypervisor interface
> > > > > + * @parm domid the domain to get information from
> > > > > + * @parm console_domid the domid of the backend console
> > > > > + * @parm gfn the guest pfn to be used as the ring buffer
> > > > > + * @parm evtchn the event channel to be used for events
> > > > > + * @return 0 on success, negative error on failure
> > > > > + */
> > > > > +int xc_dom_vpl011_init(xc_interface *xch,
> > > > > +                       uint32_t domid,
> > > > > +                       uint32_t console_domid,
> > > > > +                       xen_pfn_t gfn,
> > > > > +                       evtchn_port_t *evtchn);
> > > > > +#endif
> > > >
> > > > Actually, the pattern is to define the xc_ function on all architecture
> > > > but only return ENOSYS where it's not implemented, see
> > > > xc_vcpu_get_extstate.
> > >
> > > Well, I think the main reason behind if to avoid dummy call to the
> > > hypervisor. But effectively the hypervisor will return a proper error.
> >
> > Actually, looking at the public header. This is because vcpu_get_extstate
> > structure is only available on x86. Whereas vpl011_init is available for all
> > the architecture even though only ARM effectively implementing it.
> >
> > But my point stands below, there is no harm to implement it for x86 as it
> > would compile on any platform.
> >
> >
> > > As the call is not made in common code, I would make this function
> > > compile on all the platform (there are nothing arch specific in it).
> Currently, xc_dom_vpl011_init() is called only if info->arch_arm.vuart
> flag is true. This check may look a bit odd in the
> common code.
I am not asking to call xc_dom_vpl011_init from common code. I am only 
asking to make this function available for anyone.
Cheers,

--
Julien Grall

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