[PATCH v7 03/12] ARM: KVM: Initial skeleton to compile KVM support

[Christoffer Dall <c.dall@virtualopensystems.com>]

From: Christoffer Dall <cdall@cs.columbia.edu>

Targets KVM support for Cortex A-15 processors.

Contains no real functionality but all the framework components,
make files, header files and some tracing functionality.

“Nothing to see here. Move along, move along..."

Most functionality is in arch/arm/kvm/* or arch/arm/include/asm/kvm_*.h.

Signed-off-by: Christoffer Dall <c.dall@virtualopensystems.com>
---
 arch/arm/Kconfig                   |    2 
 arch/arm/Makefile                  |    1 
 arch/arm/include/asm/kvm.h         |   78 ++++++++++
 arch/arm/include/asm/kvm_asm.h     |   28 ++++
 arch/arm/include/asm/kvm_emulate.h |   97 +++++++++++++
 arch/arm/include/asm/kvm_host.h    |  116 +++++++++++++++
 arch/arm/include/asm/kvm_para.h    |    9 +
 arch/arm/include/asm/unified.h     |   12 ++
 arch/arm/kvm/Kconfig               |   44 ++++++
 arch/arm/kvm/Makefile              |   17 ++
 arch/arm/kvm/arm.c                 |  279 ++++++++++++++++++++++++++++++++++++
 arch/arm/kvm/emulate.c             |  125 ++++++++++++++++
 arch/arm/kvm/exports.c             |   16 ++
 arch/arm/kvm/guest.c               |  148 +++++++++++++++++++
 arch/arm/kvm/init.S                |   17 ++
 arch/arm/kvm/interrupts.S          |   17 ++
 arch/arm/kvm/mmu.c                 |   15 ++
 arch/arm/kvm/trace.h               |   52 +++++++
 arch/arm/mm/Kconfig                |   10 +
 19 files changed, 1083 insertions(+), 0 deletions(-)
 create mode 100644 arch/arm/include/asm/kvm.h
 create mode 100644 arch/arm/include/asm/kvm_asm.h
 create mode 100644 arch/arm/include/asm/kvm_emulate.h
 create mode 100644 arch/arm/include/asm/kvm_host.h
 create mode 100644 arch/arm/include/asm/kvm_para.h
 create mode 100644 arch/arm/kvm/Kconfig
 create mode 100644 arch/arm/kvm/Makefile
 create mode 100644 arch/arm/kvm/arm.c
 create mode 100644 arch/arm/kvm/emulate.c
 create mode 100644 arch/arm/kvm/exports.c
 create mode 100644 arch/arm/kvm/guest.c
 create mode 100644 arch/arm/kvm/init.S
 create mode 100644 arch/arm/kvm/interrupts.S
 create mode 100644 arch/arm/kvm/mmu.c
 create mode 100644 arch/arm/kvm/trace.h

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 3c3c054..7299c03 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -2263,3 +2263,5 @@ source "security/Kconfig"
 source "crypto/Kconfig"
 
 source "lib/Kconfig"
+
+source "arch/arm/kvm/Kconfig"
diff --git a/arch/arm/Makefile b/arch/arm/Makefile
index 1683bfb..4f99c5f 100644
--- a/arch/arm/Makefile
+++ b/arch/arm/Makefile
@@ -252,6 +252,7 @@ core-$(CONFIG_VFP)		+= arch/arm/vfp/
 
 # If we have a machine-specific directory, then include it in the build.
 core-y				+= arch/arm/kernel/ arch/arm/mm/ arch/arm/common/
+core-y 				+= arch/arm/kvm/
 core-y				+= $(machdirs) $(platdirs)
 
 drivers-$(CONFIG_OPROFILE)      += arch/arm/oprofile/
diff --git a/arch/arm/include/asm/kvm.h b/arch/arm/include/asm/kvm.h
new file mode 100644
index 0000000..c8466b7
--- /dev/null
+++ b/arch/arm/include/asm/kvm.h
@@ -0,0 +1,78 @@
+/*
+ * 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.
+ *
+ */
+
+#ifndef __ARM_KVM_H__
+#define __ARM_KVM_H__
+
+#include <asm/types.h>
+
+#define __KVM_HAVE_GUEST_DEBUG
+
+/*
+ * Modes used for short-hand mode determinition in the world-switch code and
+ * in emulation code.
+ *
+ * Note: These indices do NOT correspond to the value of the CPSR mode bits!
+ */
+enum vcpu_mode {
+	MODE_FIQ = 0,
+	MODE_IRQ,
+	MODE_SVC,
+	MODE_ABT,
+	MODE_UND,
+	MODE_USR,
+	MODE_SYS
+};
+
+struct kvm_regs {
+	__u32 regs0_7[8];	/* Unbanked regs. (r0 - r7)	   */
+	__u32 fiq_regs8_12[5];	/* Banked fiq regs. (r8 - r12)	   */
+	__u32 usr_regs8_12[5];	/* Banked usr registers (r8 - r12) */
+	__u32 reg13[6];		/* Banked r13, indexed by MODE_	   */
+	__u32 reg14[6];		/* Banked r13, indexed by MODE_	   */
+	__u32 reg15;
+	__u32 cpsr;
+	__u32 spsr[5];		/* Banked SPSR,  indexed by MODE_  */
+	struct {
+		__u32 c0_midr;
+		__u32 c1_sys;
+		__u32 c2_base0;
+		__u32 c2_base1;
+		__u32 c2_control;
+		__u32 c3_dacr;
+	} cp15;
+
+};
+
+struct kvm_sregs {
+};
+
+struct kvm_fpu {
+};
+
+struct kvm_guest_debug_arch {
+};
+
+struct kvm_debug_exit_arch {
+};
+
+struct kvm_sync_regs {
+};
+
+struct kvm_arch_memory_slot {
+};
+
+#endif /* __ARM_KVM_H__ */
diff --git a/arch/arm/include/asm/kvm_asm.h b/arch/arm/include/asm/kvm_asm.h
new file mode 100644
index 0000000..c3d4458
--- /dev/null
+++ b/arch/arm/include/asm/kvm_asm.h
@@ -0,0 +1,28 @@
+/*
+ * 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.
+ *
+ */
+
+#ifndef __ARM_KVM_ASM_H__
+#define __ARM_KVM_ASM_H__
+
+#define ARM_EXCEPTION_RESET	  0
+#define ARM_EXCEPTION_UNDEFINED   1
+#define ARM_EXCEPTION_SOFTWARE    2
+#define ARM_EXCEPTION_PREF_ABORT  3
+#define ARM_EXCEPTION_DATA_ABORT  4
+#define ARM_EXCEPTION_IRQ	  5
+#define ARM_EXCEPTION_FIQ	  6
+
+#endif /* __ARM_KVM_ASM_H__ */
diff --git a/arch/arm/include/asm/kvm_emulate.h b/arch/arm/include/asm/kvm_emulate.h
new file mode 100644
index 0000000..7ab696d
--- /dev/null
+++ b/arch/arm/include/asm/kvm_emulate.h
@@ -0,0 +1,97 @@
+/*
+ * 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.
+ *
+ */
+
+#ifndef __ARM_KVM_EMULATE_H__
+#define __ARM_KVM_EMULATE_H__
+
+#include <linux/kvm_host.h>
+#include <asm/kvm_asm.h>
+
+u32 *vcpu_reg_mode(struct kvm_vcpu *vcpu, u8 reg_num, enum vcpu_mode mode);
+
+static inline enum vcpu_mode vcpu_mode(struct kvm_vcpu *vcpu)
+{
+	u8 modes_table[16] = {
+		MODE_USR,	/* 0x0 */
+		MODE_FIQ,	/* 0x1 */
+		MODE_IRQ,	/* 0x2 */
+		MODE_SVC,	/* 0x3 */
+		0xf, 0xf, 0xf,
+		MODE_ABT,	/* 0x7 */
+		0xf, 0xf, 0xf,
+		MODE_UND,	/* 0xb */
+		0xf, 0xf, 0xf,
+		MODE_SYS};	/* 0xf */
+
+	BUG_ON(modes_table[vcpu->arch.regs.cpsr & 0xf] == 0xf);
+	return modes_table[vcpu->arch.regs.cpsr & 0xf];
+}
+
+/*
+ * Return the SPSR for the specified mode of the virtual CPU.
+ */
+static inline u32 *vcpu_spsr_mode(struct kvm_vcpu *vcpu, enum vcpu_mode mode)
+{
+	switch (mode) {
+	case MODE_SVC:
+		return &vcpu->arch.regs.svc_regs[2];
+	case MODE_ABT:
+		return &vcpu->arch.regs.abt_regs[2];
+	case MODE_UND:
+		return &vcpu->arch.regs.und_regs[2];
+	case MODE_IRQ:
+		return &vcpu->arch.regs.irq_regs[2];
+	case MODE_FIQ:
+		return &vcpu->arch.regs.fiq_regs[7];
+	default:
+		BUG();
+	}
+}
+
+/* Get vcpu register for current mode */
+static inline u32 *vcpu_reg(struct kvm_vcpu *vcpu, unsigned long reg_num)
+{
+	return vcpu_reg_mode(vcpu, reg_num, vcpu_mode(vcpu));
+}
+
+static inline u32 *vcpu_pc(struct kvm_vcpu *vcpu)
+{
+	return vcpu_reg(vcpu, 15);
+}
+
+static inline u32 *vcpu_cpsr(struct kvm_vcpu *vcpu)
+{
+	return &vcpu->arch.regs.cpsr;
+}
+
+/* Get vcpu SPSR for current mode */
+static inline u32 *vcpu_spsr(struct kvm_vcpu *vcpu)
+{
+	return vcpu_spsr_mode(vcpu, vcpu_mode(vcpu));
+}
+
+static inline bool mode_has_spsr(struct kvm_vcpu *vcpu)
+{
+	return (vcpu_mode(vcpu) < MODE_USR);
+}
+
+static inline bool vcpu_mode_priv(struct kvm_vcpu *vcpu)
+{
+	BUG_ON(vcpu_mode(vcpu) > MODE_SYS);
+	return vcpu_mode(vcpu) != MODE_USR;
+}
+
+#endif /* __ARM_KVM_EMULATE_H__ */
diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
new file mode 100644
index 0000000..2d611df
--- /dev/null
+++ b/arch/arm/include/asm/kvm_host.h
@@ -0,0 +1,116 @@
+/*
+ * 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.
+ *
+ */
+
+#ifndef __ARM_KVM_HOST_H__
+#define __ARM_KVM_HOST_H__
+
+#define KVM_MAX_VCPUS 1
+#define KVM_MEMORY_SLOTS 32
+#define KVM_PRIVATE_MEM_SLOTS 4
+#define KVM_COALESCED_MMIO_PAGE_OFFSET 1
+
+/* We don't currently support large pages. */
+#define KVM_HPAGE_GFN_SHIFT(x)	0
+#define KVM_NR_PAGE_SIZES	1
+#define KVM_PAGES_PER_HPAGE(x)	(1UL<<31)
+
+struct kvm_vcpu;
+u32 *kvm_vcpu_reg(struct kvm_vcpu *vcpu, u8 reg_num, u32 mode);
+
+struct kvm_arch {
+	/* The VMID used for the virt. memory system */
+	u64    vmid;
+
+	/* 1-level 2nd stage table and lock */
+	struct mutex pgd_mutex;
+	pgd_t *pgd;
+
+	/* VTTBR value associated with above pgd and vmid */
+	u64    vttbr;
+};
+
+#define EXCEPTION_NONE      0
+#define EXCEPTION_RESET     0x80
+#define EXCEPTION_UNDEFINED 0x40
+#define EXCEPTION_SOFTWARE  0x20
+#define EXCEPTION_PREFETCH  0x10
+#define EXCEPTION_DATA      0x08
+#define EXCEPTION_IMPRECISE 0x04
+#define EXCEPTION_IRQ       0x02
+#define EXCEPTION_FIQ       0x01
+
+struct kvm_vcpu_regs {
+	u32 usr_regs[15];	/* R0_usr - R14_usr */
+	u32 svc_regs[3];	/* SP_svc, LR_svc, SPSR_svc */
+	u32 abt_regs[3];	/* SP_abt, LR_abt, SPSR_abt */
+	u32 und_regs[3];	/* SP_und, LR_und, SPSR_und */
+	u32 irq_regs[3];	/* SP_irq, LR_irq, SPSR_irq */
+	u32 fiq_regs[8];	/* R8_fiq - R14_fiq, SPSR_fiq */
+	u32 pc;			/* The program counter (r15) */
+	u32 cpsr;		/* The guest CPSR */
+} __packed;
+
+enum cp15_regs {
+	c0_MIDR,		/* Main ID Register */
+	c0_MPIDR,		/* MultiProcessor ID Register */
+	c1_SCTLR,		/* System Control Register */
+	c1_ACTLR,		/* Auxilliary Control Register */
+	c1_CPACR,		/* Coprocessor Access Control */
+	c2_TTBR0,		/* Translation Table Base Register 0 */
+	c2_TTBR0_high,		/* TTBR0 top 32 bits */
+	c2_TTBR1,		/* Translation Table Base Register 1 */
+	c2_TTBR1_high,		/* TTBR1 top 32 bits */
+	c2_TTBCR,		/* Translation Table Base Control R. */
+	c3_DACR,		/* Domain Access Control Register */
+	c10_PRRR,		/* Primary Region Remap Register */
+	c10_NMRR,		/* Normal Memory Remap Register */
+	c13_CID,		/* Context ID Register */
+	c13_TID_URW,		/* Thread ID, User R/W */
+	c13_TID_URO,		/* Thread ID, User R/O */
+	c13_TID_PRIV,		/* Thread ID, Priveleged */
+
+	nr_cp15_regs
+};
+
+struct kvm_vcpu_arch {
+	struct kvm_vcpu_regs regs;
+
+	/* System control coprocessor (cp15) */
+	u32 cp15[nr_cp15_regs];
+
+	/* Exception Information */
+	u32 hsr;		/* Hyp Syndrom Register */
+	u32 hdfar;		/* Hyp Data Fault Address Register */
+	u32 hifar;		/* Hyp Inst. Fault Address Register */
+	u32 hpfar;		/* Hyp IPA Fault Address Register */
+
+	/* IO related fields */
+	u32 mmio_rd;
+
+	/* Interrupt related fields */
+	u32 irq_lines;		/* IRQ and FIQ levels */
+	u32 wait_for_interrupts;
+};
+
+struct kvm_vm_stat {
+	u32 remote_tlb_flush;
+};
+
+struct kvm_vcpu_stat {
+	u32 halt_wakeup;
+};
+
+#endif /* __ARM_KVM_HOST_H__ */
diff --git a/arch/arm/include/asm/kvm_para.h b/arch/arm/include/asm/kvm_para.h
new file mode 100644
index 0000000..ea686f6
--- /dev/null
+++ b/arch/arm/include/asm/kvm_para.h
@@ -0,0 +1,9 @@
+#ifndef _ASM_ARM_KVM_PARA_H
+#define _ASM_ARM_KVM_PARA_H
+
+static inline unsigned int kvm_arch_para_features(void)
+{
+	return 0;
+}
+
+#endif /* _ASM_ARM_KVM_PARA_H */
diff --git a/arch/arm/include/asm/unified.h b/arch/arm/include/asm/unified.h
index f5989f4..e5dc5f6 100644
--- a/arch/arm/include/asm/unified.h
+++ b/arch/arm/include/asm/unified.h
@@ -54,6 +54,18 @@
 
 #endif	/* CONFIG_THUMB2_KERNEL */
 
+#ifdef CONFIG_KVM_ARM_HOST
+#ifdef __ASSEMBLY__
+.arch_extension sec
+.arch_extension virt
+#else
+__asm__(
+"	.arch_extension sec\n"
+"	.arch_extension virt\n"
+);
+#endif
+#endif
+
 #ifndef CONFIG_ARM_ASM_UNIFIED
 
 /*
diff --git a/arch/arm/kvm/Kconfig b/arch/arm/kvm/Kconfig
new file mode 100644
index 0000000..83abbe0
--- /dev/null
+++ b/arch/arm/kvm/Kconfig
@@ -0,0 +1,44 @@
+#
+# KVM configuration
+#
+
+source "virt/kvm/Kconfig"
+
+menuconfig VIRTUALIZATION
+	bool "Virtualization"
+	---help---
+	  Say Y here to get to see options for using your Linux host to run
+	  other operating systems inside virtual machines (guests).
+	  This option alone does not add any kernel code.
+
+	  If you say N, all options in this submenu will be skipped and
+	  disabled.
+
+if VIRTUALIZATION
+
+config KVM
+	tristate "Kernel-based Virtual Machine (KVM) support"
+	select PREEMPT_NOTIFIERS
+	select ANON_INODES
+	select KVM_MMIO
+	depends on CPU_V7 && ARM_VIRT_EXT
+	---help---
+	  Support hosting virtualized guest machines. You will also
+	  need to select one or more of the processor modules below.
+
+	  This module provides access to the hardware capabilities through
+	  a character device node named /dev/kvm.
+
+	  If unsure, say N.
+
+config KVM_ARM_HOST
+	bool "KVM host support for ARM cpus."
+	depends on KVM
+	depends on MMU
+	depends on CPU_V7 && ARM_VIRT_EXT
+	---help---
+	  Provides host support for ARM processors.
+
+source drivers/virtio/Kconfig
+
+endif # VIRTUALIZATION
diff --git a/arch/arm/kvm/Makefile b/arch/arm/kvm/Makefile
new file mode 100644
index 0000000..e69a8e1
--- /dev/null
+++ b/arch/arm/kvm/Makefile
@@ -0,0 +1,17 @@
+#
+# Makefile for Kernel-based Virtual Machine module
+#
+
+ccflags-y += -Ivirt/kvm -Iarch/arm/kvm
+CFLAGS_arm.o     := -I.
+CFLAGS_mmu.o := -I.
+
+AFLAGS_interrupts.o := -I$(obj)
+
+obj-$(CONFIG_KVM_ARM_HOST) += init.o interrupts.o exports.o
+
+kvm-arm-y += $(addprefix ../../../virt/kvm/, kvm_main.o coalesced_mmio.o)
+
+kvm-arm-y += arm.o guest.o mmu.o emulate.o
+
+obj-$(CONFIG_KVM) += kvm-arm.o
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
new file mode 100644
index 0000000..5992d90
--- /dev/null
+++ b/arch/arm/kvm/arm.c
@@ -0,0 +1,279 @@
+/*
+ * 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.
+ *
+ */
+
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/kvm_host.h>
+#include <linux/module.h>
+#include <linux/vmalloc.h>
+#include <linux/fs.h>
+#include <linux/mman.h>
+#include <linux/sched.h>
+#include <trace/events/kvm.h>
+
+#define CREATE_TRACE_POINTS
+#include "trace.h"
+
+#include <asm/unified.h>
+#include <asm/uaccess.h>
+#include <asm/ptrace.h>
+#include <asm/mman.h>
+
+int kvm_arch_hardware_enable(void *garbage)
+{
+	return 0;
+}
+
+int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu)
+{
+	return 1;
+}
+
+void kvm_arch_hardware_disable(void *garbage)
+{
+}
+
+int kvm_arch_hardware_setup(void)
+{
+	return 0;
+}
+
+void kvm_arch_hardware_unsetup(void)
+{
+}
+
+void kvm_arch_check_processor_compat(void *rtn)
+{
+	*(int *)rtn = 0;
+}
+
+void kvm_arch_sync_events(struct kvm *kvm)
+{
+}
+
+int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
+{
+	if (type)
+		return -EINVAL;
+
+	return 0;
+}
+
+int kvm_arch_vcpu_fault(struct kvm_vcpu *vcpu, struct vm_fault *vmf)
+{
+	return VM_FAULT_SIGBUS;
+}
+
+void kvm_arch_free_memslot(struct kvm_memory_slot *free,
+			   struct kvm_memory_slot *dont)
+{
+}
+
+int kvm_arch_create_memslot(struct kvm_memory_slot *slot, unsigned long npages)
+{
+	return 0;
+}
+
+void kvm_arch_destroy_vm(struct kvm *kvm)
+{
+	int i;
+
+	for (i = 0; i < KVM_MAX_VCPUS; ++i) {
+		if (kvm->vcpus[i]) {
+			kvm_arch_vcpu_free(kvm->vcpus[i]);
+			kvm->vcpus[i] = NULL;
+		}
+	}
+}
+
+int kvm_dev_ioctl_check_extension(long ext)
+{
+	int r;
+	switch (ext) {
+	case KVM_CAP_USER_MEMORY:
+	case KVM_CAP_DESTROY_MEMORY_REGION_WORKS:
+		r = 1;
+		break;
+	case KVM_CAP_COALESCED_MMIO:
+		r = KVM_COALESCED_MMIO_PAGE_OFFSET;
+		break;
+	default:
+		r = 0;
+		break;
+	}
+	return r;
+}
+
+long kvm_arch_dev_ioctl(struct file *filp,
+			unsigned int ioctl, unsigned long arg)
+{
+	return -EINVAL;
+}
+
+int kvm_arch_set_memory_region(struct kvm *kvm,
+			       struct kvm_userspace_memory_region *mem,
+			       struct kvm_memory_slot old,
+			       int user_alloc)
+{
+	return 0;
+}
+
+int kvm_arch_prepare_memory_region(struct kvm *kvm,
+				   struct kvm_memory_slot *memslot,
+				   struct kvm_memory_slot old,
+				   struct kvm_userspace_memory_region *mem,
+				   int user_alloc)
+{
+	return 0;
+}
+
+void kvm_arch_commit_memory_region(struct kvm *kvm,
+				   struct kvm_userspace_memory_region *mem,
+				   struct kvm_memory_slot old,
+				   int user_alloc)
+{
+}
+
+void kvm_arch_flush_shadow(struct kvm *kvm)
+{
+}
+
+struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, unsigned int id)
+{
+	int err;
+	struct kvm_vcpu *vcpu;
+
+	vcpu = kmem_cache_zalloc(kvm_vcpu_cache, GFP_KERNEL);
+	if (!vcpu) {
+		err = -ENOMEM;
+		goto out;
+	}
+
+	err = kvm_vcpu_init(vcpu, kvm, id);
+	if (err)
+		goto free_vcpu;
+
+	return vcpu;
+free_vcpu:
+	kmem_cache_free(kvm_vcpu_cache, vcpu);
+out:
+	return ERR_PTR(err);
+}
+
+void kvm_arch_vcpu_free(struct kvm_vcpu *vcpu)
+{
+}
+
+void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
+{
+	kvm_arch_vcpu_free(vcpu);
+}
+
+int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu)
+{
+	return 0;
+}
+
+int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
+{
+	return 0;
+}
+
+void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu)
+{
+}
+
+void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
+{
+}
+
+void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
+{
+}
+
+int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
+					struct kvm_guest_debug *dbg)
+{
+	return -EINVAL;
+}
+
+
+int kvm_arch_vcpu_ioctl_get_mpstate(struct kvm_vcpu *vcpu,
+				    struct kvm_mp_state *mp_state)
+{
+	return -EINVAL;
+}
+
+int kvm_arch_vcpu_ioctl_set_mpstate(struct kvm_vcpu *vcpu,
+				    struct kvm_mp_state *mp_state)
+{
+	return -EINVAL;
+}
+
+int kvm_arch_vcpu_runnable(struct kvm_vcpu *v)
+{
+	return 0;
+}
+
+int kvm_arch_vcpu_in_guest_mode(struct kvm_vcpu *v)
+{
+	return 0;
+}
+
+int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
+{
+	return -EINVAL;
+}
+
+long kvm_arch_vcpu_ioctl(struct file *filp,
+			 unsigned int ioctl, unsigned long arg)
+{
+	return -EINVAL;
+}
+
+int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log)
+{
+	return -EINVAL;
+}
+
+long kvm_arch_vm_ioctl(struct file *filp,
+		       unsigned int ioctl, unsigned long arg)
+{
+	return -EINVAL;
+}
+
+int kvm_arch_init(void *opaque)
+{
+	return 0;
+}
+
+void kvm_arch_exit(void)
+{
+}
+
+static int arm_init(void)
+{
+	int rc = kvm_init(NULL, sizeof(struct kvm_vcpu), 0, THIS_MODULE);
+	return rc;
+}
+
+static void __exit arm_exit(void)
+{
+	kvm_exit();
+}
+
+module_init(arm_init);
+module_exit(arm_exit)
diff --git a/arch/arm/kvm/emulate.c b/arch/arm/kvm/emulate.c
new file mode 100644
index 0000000..0e5bd90
--- /dev/null
+++ b/arch/arm/kvm/emulate.c
@@ -0,0 +1,125 @@
+/*
+ * 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.
+ *
+ */
+
+#include <asm/kvm_emulate.h>
+
+#define REG_OFFSET(_reg) \
+	(offsetof(struct kvm_vcpu_regs, _reg) / sizeof(u32))
+
+#define USR_REG_OFFSET(_num) REG_OFFSET(usr_regs[_num])
+
+static const unsigned long vcpu_reg_offsets[MODE_SYS + 1][16] = {
+	/* FIQ Registers */
+	{
+		USR_REG_OFFSET(0), USR_REG_OFFSET(1), USR_REG_OFFSET(2),
+		USR_REG_OFFSET(3), USR_REG_OFFSET(4), USR_REG_OFFSET(5),
+		USR_REG_OFFSET(6), USR_REG_OFFSET(7),
+		REG_OFFSET(fiq_regs[1]), /* r8 */
+		REG_OFFSET(fiq_regs[1]), /* r9 */
+		REG_OFFSET(fiq_regs[2]), /* r10 */
+		REG_OFFSET(fiq_regs[3]), /* r11 */
+		REG_OFFSET(fiq_regs[4]), /* r12 */
+		REG_OFFSET(fiq_regs[5]), /* r13 */
+		REG_OFFSET(fiq_regs[6]), /* r14 */
+		REG_OFFSET(pc)		 /* r15 */
+	},
+
+	/* IRQ Registers */
+	{
+		USR_REG_OFFSET(0), USR_REG_OFFSET(1), USR_REG_OFFSET(2),
+		USR_REG_OFFSET(3), USR_REG_OFFSET(4), USR_REG_OFFSET(5),
+		USR_REG_OFFSET(6), USR_REG_OFFSET(7), USR_REG_OFFSET(8),
+		USR_REG_OFFSET(9), USR_REG_OFFSET(10), USR_REG_OFFSET(11),
+		USR_REG_OFFSET(12),
+		REG_OFFSET(irq_regs[0]), /* r13 */
+		REG_OFFSET(irq_regs[1]), /* r14 */
+		REG_OFFSET(pc)	         /* r15 */
+	},
+
+	/* SVC Registers */
+	{
+		USR_REG_OFFSET(0), USR_REG_OFFSET(1), USR_REG_OFFSET(2),
+		USR_REG_OFFSET(3), USR_REG_OFFSET(4), USR_REG_OFFSET(5),
+		USR_REG_OFFSET(6), USR_REG_OFFSET(7), USR_REG_OFFSET(8),
+		USR_REG_OFFSET(9), USR_REG_OFFSET(10), USR_REG_OFFSET(11),
+		USR_REG_OFFSET(12),
+		REG_OFFSET(svc_regs[0]), /* r13 */
+		REG_OFFSET(svc_regs[1]), /* r14 */
+		REG_OFFSET(pc)		 /* r15 */
+	},
+
+	/* ABT Registers */
+	{
+		USR_REG_OFFSET(0), USR_REG_OFFSET(1), USR_REG_OFFSET(2),
+		USR_REG_OFFSET(3), USR_REG_OFFSET(4), USR_REG_OFFSET(5),
+		USR_REG_OFFSET(6), USR_REG_OFFSET(7), USR_REG_OFFSET(8),
+		USR_REG_OFFSET(9), USR_REG_OFFSET(10), USR_REG_OFFSET(11),
+		USR_REG_OFFSET(12),
+		REG_OFFSET(abt_regs[0]), /* r13 */
+		REG_OFFSET(abt_regs[1]), /* r14 */
+		REG_OFFSET(pc)	         /* r15 */
+	},
+
+	/* UND Registers */
+	{
+		USR_REG_OFFSET(0), USR_REG_OFFSET(1), USR_REG_OFFSET(2),
+		USR_REG_OFFSET(3), USR_REG_OFFSET(4), USR_REG_OFFSET(5),
+		USR_REG_OFFSET(6), USR_REG_OFFSET(7), USR_REG_OFFSET(8),
+		USR_REG_OFFSET(9), USR_REG_OFFSET(10), USR_REG_OFFSET(11),
+		USR_REG_OFFSET(12),
+		REG_OFFSET(und_regs[0]), /* r13 */
+		REG_OFFSET(und_regs[1]), /* r14 */
+		REG_OFFSET(pc)	         /* r15 */
+	},
+
+	/* USR Registers */
+	{
+		USR_REG_OFFSET(0), USR_REG_OFFSET(1), USR_REG_OFFSET(2),
+		USR_REG_OFFSET(3), USR_REG_OFFSET(4), USR_REG_OFFSET(5),
+		USR_REG_OFFSET(6), USR_REG_OFFSET(7), USR_REG_OFFSET(8),
+		USR_REG_OFFSET(9), USR_REG_OFFSET(10), USR_REG_OFFSET(11),
+		USR_REG_OFFSET(12),
+		REG_OFFSET(usr_regs[13]), /* r13 */
+		REG_OFFSET(usr_regs[14]), /* r14 */
+		REG_OFFSET(pc)	          /* r15 */
+	},
+
+	/* SYS Registers */
+	{
+		USR_REG_OFFSET(0), USR_REG_OFFSET(1), USR_REG_OFFSET(2),
+		USR_REG_OFFSET(3), USR_REG_OFFSET(4), USR_REG_OFFSET(5),
+		USR_REG_OFFSET(6), USR_REG_OFFSET(7), USR_REG_OFFSET(8),
+		USR_REG_OFFSET(9), USR_REG_OFFSET(10), USR_REG_OFFSET(11),
+		USR_REG_OFFSET(12),
+		REG_OFFSET(usr_regs[13]), /* r13 */
+		REG_OFFSET(usr_regs[14]), /* r14 */
+		REG_OFFSET(pc)	          /* r15 */
+	},
+};
+
+/*
+ * Return a pointer to the register number valid in the specified mode of
+ * the virtual CPU.
+ */
+u32 *vcpu_reg_mode(struct kvm_vcpu *vcpu, u8 reg_num, u32 mode)
+{
+	u32 *reg_array = (u32 *)&vcpu->arch.regs;
+
+	BUG_ON(reg_num > 15);
+	BUG_ON(mode > MODE_SYS);
+
+	return reg_array + vcpu_reg_offsets[mode][reg_num];
+}
diff --git a/arch/arm/kvm/exports.c b/arch/arm/kvm/exports.c
new file mode 100644
index 0000000..d8a7fd5
--- /dev/null
+++ b/arch/arm/kvm/exports.c
@@ -0,0 +1,16 @@
+/*
+ * 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.
+ */
+
+#include <linux/module.h>
diff --git a/arch/arm/kvm/guest.c b/arch/arm/kvm/guest.c
new file mode 100644
index 0000000..9c75ec4
--- /dev/null
+++ b/arch/arm/kvm/guest.c
@@ -0,0 +1,148 @@
+/*
+ * 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.
+ *
+ */
+
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/kvm_host.h>
+#include <linux/module.h>
+#include <linux/vmalloc.h>
+#include <linux/fs.h>
+#include <asm/uaccess.h>
+#include <asm/kvm_asm.h>
+#include <asm/kvm_emulate.h>
+
+
+struct kvm_stats_debugfs_item debugfs_entries[] = {
+	{ NULL }
+};
+
+int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu)
+{
+	return 0;
+}
+
+int kvm_arch_vcpu_ioctl_get_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs)
+{
+	struct kvm_vcpu_regs *vcpu_regs = &vcpu->arch.regs;
+
+	/*
+	 * GPRs and PSRs
+	 */
+	memcpy(regs->regs0_7, &(vcpu_regs->usr_regs[0]), sizeof(u32) * 8);
+	memcpy(regs->usr_regs8_12, &(vcpu_regs->usr_regs[8]), sizeof(u32) * 5);
+	memcpy(regs->fiq_regs8_12, &(vcpu_regs->fiq_regs[0]), sizeof(u32) * 5);
+	regs->reg13[MODE_FIQ] = vcpu_regs->fiq_regs[5];
+	regs->reg14[MODE_FIQ] = vcpu_regs->fiq_regs[6];
+	regs->reg13[MODE_IRQ] = vcpu_regs->irq_regs[0];
+	regs->reg14[MODE_IRQ] = vcpu_regs->irq_regs[1];
+	regs->reg13[MODE_SVC] = vcpu_regs->svc_regs[0];
+	regs->reg14[MODE_SVC] = vcpu_regs->svc_regs[1];
+	regs->reg13[MODE_ABT] = vcpu_regs->abt_regs[0];
+	regs->reg14[MODE_ABT] = vcpu_regs->abt_regs[1];
+	regs->reg13[MODE_UND] = vcpu_regs->und_regs[0];
+	regs->reg14[MODE_UND] = vcpu_regs->und_regs[1];
+	regs->reg13[MODE_USR] = vcpu_regs->usr_regs[0];
+	regs->reg14[MODE_USR] = vcpu_regs->usr_regs[1];
+
+	regs->spsr[MODE_FIQ]  = vcpu_regs->fiq_regs[7];
+	regs->spsr[MODE_IRQ]  = vcpu_regs->irq_regs[2];
+	regs->spsr[MODE_SVC]  = vcpu_regs->svc_regs[2];
+	regs->spsr[MODE_ABT]  = vcpu_regs->abt_regs[2];
+	regs->spsr[MODE_UND]  = vcpu_regs->und_regs[2];
+
+	regs->reg15 = vcpu_regs->pc;
+	regs->cpsr = vcpu_regs->cpsr;
+
+
+	/*
+	 * Co-processor registers.
+	 */
+	regs->cp15.c0_midr = vcpu->arch.cp15[c0_MIDR];
+	regs->cp15.c1_sys = vcpu->arch.cp15[c1_SCTLR];
+	regs->cp15.c2_base0 = vcpu->arch.cp15[c2_TTBR0];
+	regs->cp15.c2_base1 = vcpu->arch.cp15[c2_TTBR1];
+	regs->cp15.c2_control = vcpu->arch.cp15[c2_TTBCR];
+	regs->cp15.c3_dacr = vcpu->arch.cp15[c3_DACR];
+
+	return 0;
+}
+
+int kvm_arch_vcpu_ioctl_set_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs)
+{
+	struct kvm_vcpu_regs *vcpu_regs = &vcpu->arch.regs;
+
+	memcpy(&(vcpu_regs->usr_regs[0]), regs->regs0_7, sizeof(u32) * 8);
+	memcpy(&(vcpu_regs->usr_regs[8]), regs->usr_regs8_12, sizeof(u32) * 5);
+	memcpy(&(vcpu_regs->fiq_regs[0]), regs->fiq_regs8_12, sizeof(u32) * 5);
+
+	vcpu_regs->fiq_regs[5] = regs->reg13[MODE_FIQ];
+	vcpu_regs->fiq_regs[6] = regs->reg14[MODE_FIQ];
+	vcpu_regs->irq_regs[0] = regs->reg13[MODE_IRQ];
+	vcpu_regs->irq_regs[1] = regs->reg14[MODE_IRQ];
+	vcpu_regs->svc_regs[0] = regs->reg13[MODE_SVC];
+	vcpu_regs->svc_regs[1] = regs->reg14[MODE_SVC];
+	vcpu_regs->abt_regs[0] = regs->reg13[MODE_ABT];
+	vcpu_regs->abt_regs[1] = regs->reg14[MODE_ABT];
+	vcpu_regs->und_regs[0] = regs->reg13[MODE_UND];
+	vcpu_regs->und_regs[1] = regs->reg14[MODE_UND];
+	vcpu_regs->usr_regs[0] = regs->reg13[MODE_USR];
+	vcpu_regs->usr_regs[1] = regs->reg14[MODE_USR];
+
+	vcpu_regs->fiq_regs[7] = regs->spsr[MODE_FIQ];
+	vcpu_regs->irq_regs[2] = regs->spsr[MODE_IRQ];
+	vcpu_regs->svc_regs[2] = regs->spsr[MODE_SVC];
+	vcpu_regs->abt_regs[2] = regs->spsr[MODE_ABT];
+	vcpu_regs->und_regs[2] = regs->spsr[MODE_UND];
+
+	/*
+	 * Co-processor registers.
+	 */
+	vcpu->arch.cp15[c0_MIDR] = regs->cp15.c0_midr;
+	vcpu->arch.cp15[c1_SCTLR] = regs->cp15.c1_sys;
+
+	vcpu_regs->pc = regs->reg15;
+	vcpu_regs->cpsr = regs->cpsr;
+
+	return 0;
+}
+
+int kvm_arch_vcpu_ioctl_get_sregs(struct kvm_vcpu *vcpu,
+				  struct kvm_sregs *sregs)
+{
+	return -EINVAL;
+}
+
+int kvm_arch_vcpu_ioctl_set_sregs(struct kvm_vcpu *vcpu,
+				  struct kvm_sregs *sregs)
+{
+	return -EINVAL;
+}
+
+int kvm_arch_vcpu_ioctl_get_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu)
+{
+	return -EINVAL;
+}
+
+int kvm_arch_vcpu_ioctl_set_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu)
+{
+	return -EINVAL;
+}
+
+int kvm_arch_vcpu_ioctl_translate(struct kvm_vcpu *vcpu,
+				  struct kvm_translation *tr)
+{
+	return -EINVAL;
+}
diff --git a/arch/arm/kvm/init.S b/arch/arm/kvm/init.S
new file mode 100644
index 0000000..073a494
--- /dev/null
+++ b/arch/arm/kvm/init.S
@@ -0,0 +1,17 @@
+/*
+ * 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.
+ *
+ */
+#include <asm/asm-offsets.h>
+#include <asm/kvm_asm.h>
diff --git a/arch/arm/kvm/interrupts.S b/arch/arm/kvm/interrupts.S
new file mode 100644
index 0000000..073a494
--- /dev/null
+++ b/arch/arm/kvm/interrupts.S
@@ -0,0 +1,17 @@
+/*
+ * 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.
+ *
+ */
+#include <asm/asm-offsets.h>
+#include <asm/kvm_asm.h>
diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
new file mode 100644
index 0000000..2cccd48
--- /dev/null
+++ b/arch/arm/kvm/mmu.c
@@ -0,0 +1,15 @@
+/*
+ * 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.
+ *
+ */
diff --git a/arch/arm/kvm/trace.h b/arch/arm/kvm/trace.h
new file mode 100644
index 0000000..f8869c1
--- /dev/null
+++ b/arch/arm/kvm/trace.h
@@ -0,0 +1,52 @@
+#if !defined(_TRACE_KVM_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_KVM_H
+
+#include <linux/tracepoint.h>
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM kvm
+
+/*
+ * Tracepoints for entry/exit to guest
+ */
+TRACE_EVENT(kvm_entry,
+	TP_PROTO(unsigned long vcpu_pc),
+	TP_ARGS(vcpu_pc),
+
+	TP_STRUCT__entry(
+		__field(	unsigned long,	vcpu_pc		)
+	),
+
+	TP_fast_assign(
+		__entry->vcpu_pc		= vcpu_pc;
+	),
+
+	TP_printk("PC: 0x%08lx", __entry->vcpu_pc)
+);
+
+TRACE_EVENT(kvm_exit,
+	TP_PROTO(unsigned long vcpu_pc),
+	TP_ARGS(vcpu_pc),
+
+	TP_STRUCT__entry(
+		__field(	unsigned long,	vcpu_pc		)
+	),
+
+	TP_fast_assign(
+		__entry->vcpu_pc		= vcpu_pc;
+	),
+
+	TP_printk("PC: 0x%08lx", __entry->vcpu_pc)
+);
+
+
+
+#endif /* _TRACE_KVM_H */
+
+#undef TRACE_INCLUDE_PATH
+#define TRACE_INCLUDE_PATH arch/arm/kvm
+#undef TRACE_INCLUDE_FILE
+#define TRACE_INCLUDE_FILE trace
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
diff --git a/arch/arm/mm/Kconfig b/arch/arm/mm/Kconfig
index 7edef91..7aba5df 100644
--- a/arch/arm/mm/Kconfig
+++ b/arch/arm/mm/Kconfig
@@ -641,6 +641,16 @@ config ARM_LPAE
 
 	  If unsure, say N.
 
+config ARM_VIRT_EXT
+	bool "Support for ARM Virtualization Extensions"
+	depends on ARM_LPAE
+	help
+	  Say Y if you have an ARMv7 processor supporting the ARM hardware
+	  Virtualization extensions. KVM depends on this feature and will
+	  not run without it being selected. If you say Y here, the kernel
+	  will not boot on a machine without virtualization extensions and
+	  will not boot as a KVM guest.
+
 config ARCH_PHYS_ADDR_T_64BIT
 	def_bool ARM_LPAE