[PATCH v3 5/6] arm64/xen: introduce CONFIG_XEN and hypercall.S on ARM64

Stefano Stabellini
2013-06-05T12:15:58Z

Introduce CONFIG_XEN and the implementation of hypercall.S (that is
the only ARMv8 specific code in Xen support for ARM).

Compile enlighten.c and grant_table.c from arch/arm.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>

Changes in v2:
- remove depends on !GENERIC_ATOMIC64;
- compile enlighten.c and grant_table.c from arch/arm directly;
- fix the privcmd implementation: according to the aarch64 procedure
call ABI the first 7 parameters are passed on registers so we don't need
to push/pop anything.

Changes in v3:
- update comment to reflect the actual hypercall calling convention.
---
arch/arm64/Kconfig | 10 +++++
arch/arm64/Makefile | 1 +
arch/arm64/xen/Makefile | 2 +
arch/arm64/xen/hypercall.S | 92 ++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 105 insertions(+), 0 deletions(-)
create mode 100644 arch/arm64/xen/Makefile
create mode 100644 arch/arm64/xen/hypercall.S

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 56b3f6d..b5d6ada 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -182,6 +182,16 @@ config HW_PERF_EVENTS

source "mm/Kconfig"

+config XEN_DOM0
+ def_bool y
+ depends on XEN
+
+config XEN
+ bool "Xen guest support on ARM64 (EXPERIMENTAL)"
+ depends on ARM64 && OF
+ help
+ Say Y if you want to run Linux in a Virtual Machine on Xen on ARM64.
+
endmenu

menu "Boot options"
diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
index c95c5cb..79dd13d 100644
--- a/arch/arm64/Makefile
+++ b/arch/arm64/Makefile
@@ -37,6 +37,7 @@ TEXT_OFFSET := 0x00080000
export TEXT_OFFSET GZFLAGS

core-y += arch/arm64/kernel/ arch/arm64/mm/
+core-$(CONFIG_XEN) += arch/arm64/xen/
libs-y := arch/arm64/lib/ $(libs-y)
libs-y += $(LIBGCC)

diff --git a/arch/arm64/xen/Makefile b/arch/arm64/xen/Makefile
new file mode 100644
index 0000000..be24040
--- /dev/null
+++ b/arch/arm64/xen/Makefile
@@ -0,0 +1,2 @@
+xen-arm-y += $(addprefix ../../arm/xen/, enlighten.o grant-table.o)
+obj-y := xen-arm.o hypercall.o
diff --git a/arch/arm64/xen/hypercall.S b/arch/arm64/xen/hypercall.S
new file mode 100644
index 0000000..71d1a49
--- /dev/null
+++ b/arch/arm64/xen/hypercall.S
@@ -0,0 +1,92 @@
+/******************************************************************************
+ * hypercall.S
+ *
+ * Xen hypercall wrappers
+ *
+ * Stefano Stabellini <stefano.stabellini@eu.citrix.com>, Citrix, 2012
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation; or, when distributed
+ * separately from the Linux kernel or incorporated into other
+ * software packages, subject to the following license:
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this source file (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy, modify,
+ * merge, publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+/*
+ * The Xen hypercall calling convention is very similar to the procedure
+ * call standard for the ARM 64-bit architecture: the first parameter is
+ * passed in x0, the second in x1, the third in x2, the fourth in x3 and
+ * the fifth in x4.
+ *
+ * The hypercall number is passed in x16.
+ *
+ * The return value is in x0.
+ *
+ * The hvc ISS is required to be 0xEA1, that is the Xen specific ARM
+ * hypercall tag.
+ *
+ * Parameter structs passed to hypercalls are laid out according to
+ * the ARM 64-bit EABI standard.
+ */
+
+#include <linux/linkage.h>
+#include <asm/assembler.h>
+#include <xen/interface/xen.h>
+
+
+#define XEN_IMM 0xEA1
+
+#define HYPERCALL_SIMPLE(hypercall) \
+ENTRY(HYPERVISOR_##hypercall) \
+ mov x16, #__HYPERVISOR_##hypercall; \
+ hvc XEN_IMM; \
+ ret; \
+ENDPROC(HYPERVISOR_##hypercall)
+
+#define HYPERCALL0 HYPERCALL_SIMPLE
+#define HYPERCALL1 HYPERCALL_SIMPLE
+#define HYPERCALL2 HYPERCALL_SIMPLE
+#define HYPERCALL3 HYPERCALL_SIMPLE
+#define HYPERCALL4 HYPERCALL_SIMPLE
+#define HYPERCALL5 HYPERCALL_SIMPLE
+
+ .text
+
+HYPERCALL2(xen_version);
+HYPERCALL3(console_io);
+HYPERCALL3(grant_table_op);
+HYPERCALL2(sched_op);
+HYPERCALL2(event_channel_op);
+HYPERCALL2(hvm_op);
+HYPERCALL2(memory_op);
+HYPERCALL2(physdev_op);
+HYPERCALL3(vcpu_op);
+
+ENTRY(privcmd_call)
+ mov x16, x0
+ mov x0, x1
+ mov x1, x2
+ mov x2, x3
+ mov x3, x4
+ mov x4, x5
+ hvc XEN_IMM
+ ret
+ENDPROC(privcmd_call);
--
1.7.2.5