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

From: Stefano Stabellini
Date: Mon Jan 18 2016 - 12:04:37 EST


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?


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.


> 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.