[PATCH 1/4] KVM: PPC: Factor out guest epapr initialization

Alexander Graf
2012-05-30T09:54:43Z

From: Liu Yu-B13201 <Yu.Liu@freescale.com>

epapr paravirtualization support is now a Kconfig
selectable option

Signed-off-by: Liu Yu <yu.liu@freescale.com>
[stuart.yoder@freescale.com: misc minor fixes, description update]
Signed-off-by: Stuart Yoder <stuart.yoder@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
---
arch/powerpc/include/asm/epapr_hcalls.h | 2 +
arch/powerpc/kernel/Makefile | 1 +
arch/powerpc/kernel/epapr_hcalls.S | 25 +++++++++++++++
arch/powerpc/kernel/epapr_paravirt.c | 52 +++++++++++++++++++++++++++++++
arch/powerpc/kernel/kvm.c | 28 ++---------------
arch/powerpc/kernel/kvm_emul.S | 10 ------
arch/powerpc/platforms/Kconfig | 9 +++++
7 files changed, 92 insertions(+), 35 deletions(-)
create mode 100644 arch/powerpc/kernel/epapr_hcalls.S
create mode 100644 arch/powerpc/kernel/epapr_paravirt.c

diff --git a/arch/powerpc/include/asm/epapr_hcalls.h b/arch/powerpc/include/asm/epapr_hcalls.h
index 976835d..bf2c06c 100644
--- a/arch/powerpc/include/asm/epapr_hcalls.h
+++ b/arch/powerpc/include/asm/epapr_hcalls.h
@@ -153,6 +153,8 @@
#define EV_HCALL_CLOBBERS2 EV_HCALL_CLOBBERS3, "r5"
#define EV_HCALL_CLOBBERS1 EV_HCALL_CLOBBERS2, "r4"

+extern bool epapr_paravirt_enabled;
+extern u32 epapr_hypercall_start[];

/*
* We use "uintptr_t" to define a register because it's guaranteed to be a
diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index 83afacd..bb282dd 100644
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile
@@ -128,6 +128,7 @@ ifneq ($(CONFIG_XMON)$(CONFIG_KEXEC),)
obj-y += ppc_save_regs.o
endif

+obj-$(CONFIG_EPAPR_PARAVIRT) += epapr_paravirt.o epapr_hcalls.o
obj-$(CONFIG_KVM_GUEST) += kvm.o kvm_emul.o

# Disable GCOV in odd or sensitive code
diff --git a/arch/powerpc/kernel/epapr_hcalls.S b/arch/powerpc/kernel/epapr_hcalls.S
new file mode 100644
index 0000000..697b390
--- /dev/null
+++ b/arch/powerpc/kernel/epapr_hcalls.S
@@ -0,0 +1,25 @@
+/*
+ * Copyright (C) 2012 Freescale Semiconductor, Inc.
+ *
+ * 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.
+ */
+
+#include <linux/threads.h>
+#include <asm/reg.h>
+#include <asm/page.h>
+#include <asm/cputable.h>
+#include <asm/thread_info.h>
+#include <asm/ppc_asm.h>
+#include <asm/asm-offsets.h>
+
+/* Hypercall entry point. Will be patched with device tree instructions. */
+.global epapr_hypercall_start
+epapr_hypercall_start:
+ li r3, -1
+ nop
+ nop
+ nop
+ blr
diff --git a/arch/powerpc/kernel/epapr_paravirt.c b/arch/powerpc/kernel/epapr_paravirt.c
new file mode 100644
index 0000000..028aeae
--- /dev/null
+++ b/arch/powerpc/kernel/epapr_paravirt.c
@@ -0,0 +1,52 @@
+/*
+ * ePAPR para-virtualization support.
+ *
+ * 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.
+ *
+ * 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, write to the Free Software
+ * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * Copyright (C) 2012 Freescale Semiconductor, Inc.
+ */
+
+#include <linux/of.h>
+#include <asm/epapr_hcalls.h>
+#include <asm/cacheflush.h>
+#include <asm/code-patching.h>
+
+bool epapr_paravirt_enabled;
+
+static int __init epapr_paravirt_init(void)
+{
+ struct device_node *hyper_node;
+ const u32 *insts;
+ int len, i;
+
+ hyper_node = of_find_node_by_path("/hypervisor");
+ if (!hyper_node)
+ return -ENODEV;
+
+ insts = of_get_property(hyper_node, "hcall-instructions", &len);
+ if (!insts)
+ return -ENODEV;
+
+ if (len % 4 || len > (4 * 4))
+ return -ENODEV;
+
+ for (i = 0; i < (len / 4); i++)
+ patch_instruction(epapr_hypercall_start + i, insts[i]);
+
+ epapr_paravirt_enabled = true;
+
+ return 0;
+}
+
+early_initcall(epapr_paravirt_init);
diff --git a/arch/powerpc/kernel/kvm.c b/arch/powerpc/kernel/kvm.c
index 62bdf23..1c13307 100644
--- a/arch/powerpc/kernel/kvm.c
+++ b/arch/powerpc/kernel/kvm.c
@@ -31,6 +31,7 @@
#include <asm/cacheflush.h>
#include <asm/disassemble.h>
#include <asm/ppc-opcode.h>
+#include <asm/epapr_hcalls.h>

#define KVM_MAGIC_PAGE (-4096L)
#define magic_var(x) KVM_MAGIC_PAGE + offsetof(struct kvm_vcpu_arch_shared, x)
@@ -726,7 +727,7 @@ unsigned long kvm_hypercall(unsigned long *in,
unsigned long register r11 asm("r11") = nr;
unsigned long register r12 asm("r12");

- asm volatile("bl kvm_hypercall_start"
+ asm volatile("bl epapr_hypercall_start"
: "=r"(r0), "=r"(r3), "=r"(r4), "=r"(r5), "=r"(r6),
"=r"(r7), "=r"(r8), "=r"(r9), "=r"(r10), "=r"(r11),
"=r"(r12)
@@ -747,29 +748,6 @@ unsigned long kvm_hypercall(unsigned long *in,
}
EXPORT_SYMBOL_GPL(kvm_hypercall);

-static int kvm_para_setup(void)
-{
- extern u32 kvm_hypercall_start;
- struct device_node *hyper_node;
- u32 *insts;
- int len, i;
-
- hyper_node = of_find_node_by_path("/hypervisor");
- if (!hyper_node)
- return -1;
-
- insts = (u32*)of_get_property(hyper_node, "hcall-instructions", &len);
- if (len % 4)
- return -1;
- if (len > (4 * 4))
- return -1;
-
- for (i = 0; i < (len / 4); i++)
- kvm_patch_ins(&(&kvm_hypercall_start)[i], insts[i]);
-
- return 0;
-}
-
static __init void kvm_free_tmp(void)
{
unsigned long start, end;
@@ -791,7 +769,7 @@ static int __init kvm_guest_init(void)
if (!kvm_para_available())
goto free_tmp;

- if (kvm_para_setup())
+ if (!epapr_paravirt_enabled)
goto free_tmp;

if (kvm_para_has_feature(KVM_FEATURE_MAGIC_PAGE))
diff --git a/arch/powerpc/kernel/kvm_emul.S b/arch/powerpc/kernel/kvm_emul.S
index e291cf3..62ceb2a 100644
--- a/arch/powerpc/kernel/kvm_emul.S
+++ b/arch/powerpc/kernel/kvm_emul.S
@@ -24,16 +24,6 @@
#include <asm/page.h>
#include <asm/asm-offsets.h>

-/* Hypercall entry point. Will be patched with device tree instructions. */
-
-.global kvm_hypercall_start
-kvm_hypercall_start:
- li r3, -1
- nop
- nop
- nop
- blr
-
#define KVM_MAGIC_PAGE (-4096)

#ifdef CONFIG_64BIT
diff --git a/arch/powerpc/platforms/Kconfig b/arch/powerpc/platforms/Kconfig
index a35ca44..e7a896a 100644
--- a/arch/powerpc/platforms/Kconfig
+++ b/arch/powerpc/platforms/Kconfig
@@ -25,6 +25,7 @@ source "arch/powerpc/platforms/wsp/Kconfig"
config KVM_GUEST
bool "KVM Guest support"
default n
+ select EPAPR_PARAVIRT
---help---
This option enables various optimizations for running under the KVM
hypervisor. Overhead for the kernel when not running inside KVM should
@@ -32,6 +33,14 @@ config KVM_GUEST

In case of doubt, say Y

+config EPAPR_PARAVIRT
+ bool "ePAPR para-virtualization support"
+ default n
+ help
+ Enables ePAPR para-virtualization support for guests.
+
+ In case of doubt, say Y
+
config PPC_NATIVE
bool
depends on 6xx || PPC64
--
1.6.0.2