Re: [PATCH 7/9] xen/x86: hook up xen_banner() also for PVH

[Juergen Gross]

On 29.09.21 09:28, Jan Beulich wrote:
> On 29.09.2021 07:45, Juergen Gross wrote:
> > On 23.09.21 17:31, Jan Beulich wrote:
> > > On 23.09.2021 17:25, Juergen Gross wrote:
> > > > On 23.09.21 17:19, Jan Beulich wrote:
> > > > > On 23.09.2021 17:15, Juergen Gross wrote:
> > > > > > On 23.09.21 17:10, Jan Beulich wrote:
> > > > > > > On 23.09.2021 16:59, Juergen Gross wrote:
> > > > > > > > On 07.09.21 12:11, Jan Beulich wrote:
> > > > > > > > > This was effectively lost while dropping PVHv1 code. Move the function
> > > > > > > > > and arrange for it to be called the same way as done in PV mode. Clearly
> > > > > > > > > this then needs re-introducing the XENFEAT_mmu_pt_update_preserve_ad
> > > > > > > > > check that was recently removed, as that's a PV-only feature.
> > > > > > > > >
> > > > > > > > > Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
> > > > > > > > >
> > > > > > > > > --- a/arch/x86/xen/enlighten.c
> > > > > > > > > +++ b/arch/x86/xen/enlighten.c
> > > > > > > > > @@ -261,6 +261,18 @@ int xen_vcpu_setup(int cpu)
> > > > > > > > >       	return ((per_cpu(xen_vcpu, cpu) == NULL) ? -ENODEV : 0);
> > > > > > > > >       }
> > > > > > > > >       
> > > > > > > > > +void __init xen_banner(void)
> > > > > > > > > +{
> > > > > > > > > +	unsigned version = HYPERVISOR_xen_version(XENVER_version, NULL);
> > > > > > > > > +	struct xen_extraversion extra;
> > > > > > > >
> > > > > > > > Please add a blank line here.
> > > > > > >
> > > > > > > Oops.
> > > > > > >
> > > > > > > > > +	HYPERVISOR_xen_version(XENVER_extraversion, &extra);
> > > > > > > > > +
> > > > > > > > > +	pr_info("Booting paravirtualized kernel on %s\n", pv_info.name);
> > > > > > > >
> > > > > > > > Is this correct? I don't think the kernel needs to be paravirtualized
> > > > > > > > with PVH (at least not to the same extend as for PV).
> > > > > > >
> > > > > > > What else do you suggest the message to say? Simply drop
> > > > > > > "paravirtualized"? To some extent it is applicable imo, further
> > > > > > > qualified by pv_info.name. And that's how it apparently was with
> > > > > > > PVHv1.
> > > > > >
> > > > > > The string could be selected depending on CONFIG_XEN_PV.
> > > > >
> > > > > Hmm, now I'm confused: Doesn't this setting control whether the kernel
> > > > > can run in PV mode? If so, that functionality being present should have
> > > > > no effect on the functionality of the kernel when running in PVH mode.
> > > > > So what you suggest would end up in misleading information imo.
> > > >
> > > > Hmm, yes, I mixed "paravirtualized" with "capable to run
> > > > paravirtualized".
> > > >
> > > > So the string should depend on xen_pv_domain().
> > >
> > > But that's already expressed by pv_info.name then being "Xen PV".
> >
> > True. Okay, I'm fine with just dropping "paravirtualized".
>
> Done. Do you want me to also make pr_info() vs printk(KERN_INFO ...)
> consistent in the function at this occasion? If so - which of the two?

pr_info(), please.


Juergen

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