Re: [Xen-devel] [PATCH v2 16/16] ARM64: XEN: Initialize Xen specific UEFI runtime services

[Stefano Stabellini]

On Fri, 22 Jan 2016, Shannon Zhao wrote:
> On 2016/1/19 1:03, Stefano Stabellini wrote:
> > On Fri, 15 Jan 2016, Shannon Zhao wrote:
> >> > From: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
> >> > 
> >> > When running on Xen hypervisor, runtime services are supported through
> >> > hypercall. So call Xen specific function to initialize runtime services.
> >> > 
> >> > Signed-off-by: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
> > Thanks Shannon, much much better!  Just a couple of questions.
> > 
> > 
> >> >  arch/arm/xen/enlighten.c |  5 +++++
> >> >  arch/arm64/xen/Makefile  |  1 +
> >> >  arch/arm64/xen/efi.c     | 36 ++++++++++++++++++++++++++++++++++++
> >> >  drivers/xen/Kconfig      |  2 +-
> >> >  include/xen/xen-ops.h    |  1 +
> >> >  5 files changed, 44 insertions(+), 1 deletion(-)
> >> >  create mode 100644 arch/arm64/xen/efi.c
> >> > 
> >> > diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
> >> > index 485e117..84f27ec 100644
> >> > --- a/arch/arm/xen/enlighten.c
> >> > +++ b/arch/arm/xen/enlighten.c
> >> > @@ -414,6 +414,11 @@ static int __init xen_guest_init(void)
> >> >  	if (xen_initial_domain())
> >> >  		pvclock_gtod_register_notifier(&xen_pvclock_gtod_notifier);
> >> >  
> >> > +	if (IS_ENABLED(CONFIG_XEN_EFI)) {
> >> > +		if (efi_enabled(EFI_PARAVIRT))
> >> > +			xen_efi_runtime_setup();
> >> > +	}
> >> > +
> >> >  	return 0;
> >> >  }
> >> >  early_initcall(xen_guest_init);
> >> > diff --git a/arch/arm64/xen/Makefile b/arch/arm64/xen/Makefile
> >> > index 74a8d87..62e6fe2 100644
> >> > --- a/arch/arm64/xen/Makefile
> >> > +++ b/arch/arm64/xen/Makefile
> >> > @@ -1,2 +1,3 @@
> >> >  xen-arm-y	+= $(addprefix ../../arm/xen/, enlighten.o grant-table.o p2m.o mm.o)
> >> >  obj-y		:= xen-arm.o hypercall.o
> >> > +obj-$(CONFIG_XEN_EFI) += efi.o
> >> > diff --git a/arch/arm64/xen/efi.c b/arch/arm64/xen/efi.c
> >> > new file mode 100644
> >> > index 0000000..33046b0
> >> > --- /dev/null
> >> > +++ b/arch/arm64/xen/efi.c
> >> > @@ -0,0 +1,36 @@
> >> > +/*
> >> > + * Copyright (c) 2015, Linaro Limited, Shannon Zhao
> >> > + *
> >> > + * This program is free software; you can redistribute it and/or modify
> >> > + * it under the terms of the GNU General Public License as published by
> >> > + * the Free Software Foundation; either version 2 of the License, or
> >> > + * (at your option) any later version.
> >> > + *
> >> > + * This program is distributed in the hope that it will be useful,
> >> > + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> >> > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> >> > + * GNU General Public License for more details.
> >> > + *
> >> > + * You should have received a copy of the GNU General Public License along
> >> > + * with this program.  If not, see <http://www.gnu.org/licenses/>.
> >> > + */
> >> > +
> >> > +#include <linux/efi.h>
> >> > +#include <xen/xen-ops.h>
> >> > +
> >> > +void __init xen_efi_runtime_setup(void)
> >> > +{
> >> > +	efi.get_time                 = xen_efi_get_time;
> >> > +	efi.set_time                 = xen_efi_set_time;
> >> > +	efi.get_wakeup_time          = xen_efi_get_wakeup_time;
> >> > +	efi.set_wakeup_time          = xen_efi_set_wakeup_time;
> >> > +	efi.get_variable             = xen_efi_get_variable;
> >> > +	efi.get_next_variable        = xen_efi_get_next_variable;
> >> > +	efi.set_variable             = xen_efi_set_variable;
> >> > +	efi.query_variable_info      = xen_efi_query_variable_info;
> >> > +	efi.update_capsule           = xen_efi_update_capsule;
> >> > +	efi.query_capsule_caps       = xen_efi_query_capsule_caps;
> >> > +	efi.get_next_high_mono_count = xen_efi_get_next_high_mono_count;
> >> > +	efi.reset_system             = NULL;
> >> > +}
> >> > +EXPORT_SYMBOL_GPL(xen_efi_runtime_setup);
> > This looks very similar to struct efi efi_xen previously in
> > drivers/xen/efi.c.  Maybe it makes sense to leave struct efi efi_xen in
> > drivers/xen/efi.c, export it in include/xen/xen-ops.h, then here just:
> > 
> >   efi = efi_xen;
> > 
> > Would that improve code readability?
> 
> Rethink about this. It's a little different on ARM since we call
> xen_efi_runtime_setup after parsing the FDT and setting some members of
> efi already, e.g. efi.systab, efi.acpi20. So it necessary to have a
> different way to initialize the struct efi.

OK, fair enough.