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

[Shannon Zhao <shannon.zhao@xxxxxxxxxx>]

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?
Ok.
> Correct me if I am wrong, but on ARM64 (differently from x86) it is not
> necessary to set efi.systab because it is not used, right? If so, it
> would be best to add a comment here to remember.
Not set efi.systab here because it gets the system table through fdt and 
set efi.systab there. See uefi_init() in arch/arm64/kernel.efi.c
        efi.systab = early_memremap(efi_system_table,
                                    sizeof(efi_system_table_t));
> > diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig
> > index 73708ac..27d216a 100644
> > --- a/drivers/xen/Kconfig
> > +++ b/drivers/xen/Kconfig
> > @@ -268,7 +268,7 @@ config XEN_HAVE_PVMMU
> >
> >   config XEN_EFI
> >         def_bool y
> > -       depends on X86_64 && EFI
> > +       depends on (ARM64 || X86_64) && EFI
> >
> >   config XEN_AUTO_XLATE
> >         def_bool y
> > diff --git a/include/xen/xen-ops.h b/include/xen/xen-ops.h
> > index c83a338..36ff8e4 100644
> > --- a/include/xen/xen-ops.h
> > +++ b/include/xen/xen-ops.h
> > @@ -107,6 +107,7 @@ efi_status_t xen_efi_update_capsule(efi_capsule_header_t 
> > **capsules,
> >   efi_status_t xen_efi_query_capsule_caps(efi_capsule_header_t **capsules,
> >                                         unsigned long count, u64 *max_size,
> >                                         int *reset_type);
> > +void xen_efi_runtime_setup(void);
> xen_efi_runtime_setup is not defined on x86, but this header is not arch
> specific.
--
Shannon

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