On Mon, 18 Jan 2016, Mark Rutland wrote:

On Fri, Jan 15, 2016 at 02:55:29PM +0800, Shannon Zhao wrote:

quoted

From: Shannon Zhao <redacted>

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 <redacted>
---
 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;
+}

How do capsules work in the absence of an EFI system reset?

Actually I don't think that capsules are available in Xen on ARM64 yet,
see "TODO - disabled until implemented on ARM" in
xen/common/efi/runtime.c.

FYI system reset is available, but it is provided via a different
mechanism (HYPERVISOR_sched_op(xen_restart...)

Are there any other mandatory features that are missing in a
Xen-provided pseudo-EFI?