Re: [PATCH v5 1/4] KVM: PPC: epapr: Factor out the epapr init

from the kvm guest paravirt init code.

Signed-off-by: Liu Yu <redacted>
---
v5:
1. fix the if test
2. use patch_instruction()
3. code cleanup
4. rename the files
5. make epapr paravirt user-selectable

 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    |   54 +++++++++++++++++++++++++++++++
 arch/powerpc/kernel/kvm.c               |   28 ++--------------
 arch/powerpc/kernel/kvm_emul.S          |   10 ------
 arch/powerpc/platforms/Kconfig          |    7 ++++
 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 f3b0c2c..0ff3f24 100644
--- a/arch/powerpc/include/asm/epapr_hcalls.h
+++ b/arch/powerpc/include/asm/epapr_hcalls.h

@@ -148,6 +148,8 @@
 #define EV_HCALL_CLOBBERS2 EV_HCALL_CLOBBERS3, "r5"
 #define EV_HCALL_CLOBBERS1 EV_HCALL_CLOBBERS2, "r4"
 
+extern bool epapr_para_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 ee728e4..ba8fa43 100644
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile

@@ -136,6 +136,7 @@ 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..e601da7
--- /dev/null
+++ b/arch/powerpc/kernel/epapr_paravirt.c

@@ -0,0 +1,54 @@
+/*
+ * 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_para_enabled = false;

+static int __init epapr_para_init(void)
+{
+	struct device_node *hyper_node;
+	const u32 *insts;
+	int len, i;
+
+	hyper_node = of_find_node_by_path("/hypervisor");
+	if (!hyper_node) {
+		printk(KERN_WARNING
+		       "ePAPR paravirt disabled: No hypervisor node found\n");
+		return -ENODEV;
+	}
+
+	insts = of_get_property(hyper_node, "hcall-instructions", &len);
+	if (insts && !(len % 4) && len <= (4 * 4)) {
+		for (i = 0; i < (len / 4); i++)
+			patch_instruction(epapr_hypercall_start + i, insts[i]);
+
+		epapr_para_enabled = true;
+	} else {
+		printk(KERN_WARNING
+		       "ePAPR paravirt disabled: No hypervisor inst found\n");
+	}