[v4,04/14] KVM: ARM: Initial skeleton to compile KVM support

Commit Message

Christoffer Dall Nov. 29, 2012, 10:36 p.m. UTC

On Mon, Nov 19, 2012 at 9:41 AM, Will Deacon <[e-mail]> wrote:
> On Sat, Nov 10, 2012 at 03:42:38PM +0000, Christoffer Dall wrote:
>> Targets KVM support for Cortex A-15 processors.
>>
>> Contains all the framework components, make files, header files, some
>> tracing functionality, and basic user space API.
>>
>> Only supported core is Cortex-A15 for now.
>>
>> Most functionality is in arch/arm/kvm/* or arch/arm/include/asm/kvm_*.h.
>>
>> Reviewed-by: Marcelo Tosatti <[e-mail]>
>> Signed-off-by: Rusty Russell <[e-mail]>
>> Signed-off-by: Marc Zyngier <[e-mail]>
>> Signed-off-by: Christoffer Dall <[e-mail]>
>
> [...]
>
>>  4.69 KVM_GET_ONE_REG
>>
>>  Capability: KVM_CAP_ONE_REG
>> @@ -1791,6 +1800,7 @@ The list of registers accessible using this interface is identical to the
>>  list in 4.68.
>>
>>
>> +
>
> Whitespace.
>
>>  4.70 KVM_KVMCLOCK_CTRL
>>
>>  Capability: KVM_CAP_KVMCLOCK_CTRL
>> @@ -2072,6 +2082,46 @@ KVM_S390_INT_EXTERNAL_CALL (vcpu) - sigp external call; source cpu in parm
>>  Note that the vcpu ioctl is asynchronous to vcpu execution.
>>
>>
>> +4.77 KVM_ARM_VCPU_INIT
>> +
>> +Capability: basic
>> +Architectures: arm
>> +Type: vcpu ioctl
>> +Parameters: struct struct kvm_vcpu_init (in)
>> +Returns: 0 on success; -1 on error
>> +Errors:
>> +  EINVAL:    the target is unknown, or the combination of features is invalid.
>> +  ENOENT:    a features bit specified is unknown.
>> +
>> +This tells KVM what type of CPU to present to the guest, and what
>> +optional features it should have.  This will cause a reset of the cpu
>> +registers to their initial values.  If this is not called, KVM_RUN will
>> +return ENOEXEC for that vcpu.
>> +
>> +Note that because some registers reflect machine topology, all vcpus
>> +should be created before this ioctl is invoked.
>> +
>> +
>> +4.78 KVM_GET_REG_LIST
>> +
>> +Capability: basic
>> +Architectures: arm
>> +Type: vcpu ioctl
>> +Parameters: struct kvm_reg_list (in/out)
>> +Returns: 0 on success; -1 on error
>> +Errors:
>> +  E2BIG:     the reg index list is too big to fit in the array specified by
>> +             the user (the number required will be written into n).
>> +
>> +struct kvm_reg_list {
>> +       __u64 n; /* number of registers in reg[] */
>> +       __u64 reg[0];
>> +};
>> +
>> +This ioctl returns the guest registers that are supported for the
>> +KVM_GET_ONE_REG/KVM_SET_ONE_REG calls.
>> +
>> +
>>  5. The kvm_run structure
>>  ------------------------
>>
>> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
>> index ade7e92..43a997a 100644
>> --- a/arch/arm/Kconfig
>> +++ b/arch/arm/Kconfig
>> @@ -2311,3 +2311,5 @@ 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 5f914fc..433becd 100644
>> --- a/arch/arm/Makefile
>> +++ b/arch/arm/Makefile
>> @@ -257,6 +257,7 @@ core-$(CONFIG_XEN)          += arch/arm/xen/
>>  core-y                         += arch/arm/kernel/ arch/arm/mm/ arch/arm/common/
>>  core-y                         += arch/arm/net/
>>  core-y                         += arch/arm/crypto/
>> +core-y                                 += arch/arm/kvm/
>
> Predicate this on CONFIG_KVM_ARM_HOST, then add some obj-y to the
> kvm/Makefile.
>
>>  core-y                         += $(machdirs) $(platdirs)
>>
>>  drivers-$(CONFIG_OPROFILE)      += arch/arm/oprofile/
>> diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
>> new file mode 100644
>> index 0000000..67826b2
>> --- /dev/null
>> +++ b/arch/arm/include/asm/kvm_host.h
>> @@ -0,0 +1,114 @@
>> +/*
>> + * Copyright (C) 2012 - Virtual Open Systems and Columbia University
>> + * Author: Christoffer Dall <[e-mail]>
>> + *
>> + * 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__
>> +
>> +#include <asm/kvm.h>
>> +#include <asm/kvm_asm.h>
>> +
>> +#define KVM_MAX_VCPUS CONFIG_KVM_ARM_MAX_VCPUS
>
> One thing I noticed when hacking kvmtool is that we don't support the
> KVM_CAP_{MAX,NR}_VCPUS capabilities. Why is this? Since we have a
> maximum of 8 due to limitations of the GIC, it might be nice to put that
> somewhere visible to userspace.
>

indeed

>> +#define KVM_MEMORY_SLOTS 32
>> +#define KVM_PRIVATE_MEM_SLOTS 4
>> +#define KVM_COALESCED_MMIO_PAGE_OFFSET 1
>> +
>> +#define KVM_VCPU_MAX_FEATURES 0
>> +
>> +/* 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);
>> +int kvm_target_cpu(void);
>> +int kvm_reset_vcpu(struct kvm_vcpu *vcpu);
>> +void kvm_reset_coprocs(struct kvm_vcpu *vcpu);
>> +
>> +struct kvm_arch {
>> +       /* VTTBR value associated with below pgd and vmid */
>> +       u64    vttbr;
>> +
>> +       /*
>> +        * Anything that is not used directly from assembly code goes
>> +        * here.
>> +        */
>> +
>> +       /* The VMID generation used for the virt. memory system */
>> +       u64    vmid_gen;
>> +       u32    vmid;
>> +
>> +       /* Stage-2 page table */
>> +       pgd_t *pgd;
>> +};
>> +
>> +#define KVM_NR_MEM_OBJS     40
>> +
>> +/*
>> + * We don't want allocation failures within the mmu code, so we preallocate
>> + * enough memory for a single page fault in a cache.
>> + */
>> +struct kvm_mmu_memory_cache {
>> +       int nobjs;
>> +       void *objects[KVM_NR_MEM_OBJS];
>> +};
>> +
>> +struct kvm_vcpu_arch {
>> +       struct kvm_regs regs;
>> +
>> +       int target; /* Processor target */
>> +       DECLARE_BITMAP(features, KVM_VCPU_MAX_FEATURES);
>> +
>> +       /* System control coprocessor (cp15) */
>> +       u32 cp15[NR_CP15_REGS];
>> +
>> +       /* The CPU type we expose to the VM */
>> +       u32 midr;
>> +
>> +       /* Exception Information */
>> +       u32 hsr;                /* Hyp Syndrom Register */
>
> pedantic: syndrome
>
>> diff --git a/arch/arm/include/uapi/asm/kvm.h b/arch/arm/include/uapi/asm/kvm.h
>> new file mode 100644
>> index 0000000..00d61a6
>> --- /dev/null
>> +++ b/arch/arm/include/uapi/asm/kvm.h
>> @@ -0,0 +1,82 @@
>> +/*
>> + * Copyright (C) 2012 - Virtual Open Systems and Columbia University
>> + * Author: Christoffer Dall <[e-mail]>
>> + *
>> + * 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>
>> +#include <asm/ptrace.h>
>> +
>> +#define __KVM_HAVE_GUEST_DEBUG
>> +
>> +#define KVM_REG_SIZE(id)                                               \
>> +       (1U << (((id) & KVM_REG_SIZE_MASK) >> KVM_REG_SIZE_SHIFT))
>> +
>> +struct kvm_regs {
>> +       struct pt_regs usr_regs;/* R0_usr - R14_usr, PC, CPSR */
>> +       __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 */
>> +};
>> +
>> +/* Supported Processor Types */
>> +#define KVM_ARM_TARGET_CORTEX_A15      0
>> +#define KVM_ARM_NUM_TARGETS            1
>
> In future, it would be nice to have a way of probing the supported
> targets, rather than trying a bunch of them and seeing which ioctl
> finally succeeds.
>
>> diff --git a/arch/arm/kvm/Kconfig b/arch/arm/kvm/Kconfig
>> new file mode 100644
>> index 0000000..c7eb178
>> --- /dev/null
>> +++ b/arch/arm/kvm/Kconfig
>> @@ -0,0 +1,55 @@
>> +#
>> +# 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
>> +       bool "Kernel-based Virtual Machine (KVM) support"
>> +       select PREEMPT_NOTIFIERS
>> +       select ANON_INODES
>> +       select KVM_MMIO
>> +       depends on ARM_VIRT_EXT && ARM_LPAE
>> +       ---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
>
> ARM_VIRT_EXT already implies CPU_V7 but, as I suggested earlier, it
> should probably imply ARM_LPAE which would make much of this simpler.
>

true, and this depends on KVM and KVM already depends on ARM_VIRT_EXT
&& ARM_LPAE, so I simply removed this line.

>> +       ---help---
>> +         Provides host support for ARM processors.
>> +
>> +config KVM_ARM_MAX_VCPUS
>> +       int "Number maximum supported virtual CPUs per VM"
>> +       depends on KVM_ARM_HOST
>> +       default 4
>> +       help
>> +         Static number of max supported virtual CPUs per VM.
>> +
>> +         If you choose a high number, the vcpu structures will be quite
>> +         large, so only choose a reasonable number that you expect to
>> +         actually use.
>> +
>> +source drivers/virtio/Kconfig
>> +
>> +endif # VIRTUALIZATION
>
> I guess the XEN config options should also be moved under here?
>

no objections

>> diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
>> new file mode 100644
>> index 0000000..ead5a4e
>> --- /dev/null
>> +++ b/arch/arm/kvm/arm.c
>
> [...]
>
>> +long kvm_arch_vcpu_ioctl(struct file *filp,
>> +                        unsigned int ioctl, unsigned long arg)
>> +{
>> +       struct kvm_vcpu *vcpu = filp->private_data;
>> +       void __user *argp = (void __user *)arg;
>> +
>> +       switch (ioctl) {
>> +       case KVM_ARM_VCPU_INIT: {
>> +               struct kvm_vcpu_init init;
>> +
>> +               if (copy_from_user(&init, argp, sizeof init))
>> +                       return -EFAULT;
>> +
>> +               return kvm_vcpu_set_target(vcpu, &init);
>> +
>> +       }
>> +       case KVM_SET_ONE_REG:
>> +       case KVM_GET_ONE_REG: {
>> +               struct kvm_one_reg reg;
>> +               if (copy_from_user(&reg, argp, sizeof(reg)))
>> +                       return -EFAULT;
>> +               if (ioctl == KVM_SET_ONE_REG)
>> +                       return kvm_arm_set_reg(vcpu, &reg);
>> +               else
>> +                       return kvm_arm_get_reg(vcpu, &reg);
>> +       }
>> +       case KVM_GET_REG_LIST: {
>> +               struct kvm_reg_list __user *user_list = argp;
>> +               struct kvm_reg_list reg_list;
>> +               unsigned n;
>> +
>> +               if (copy_from_user(&reg_list, user_list, sizeof reg_list))
>> +                       return -EFAULT;
>> +               n = reg_list.n;
>> +               reg_list.n = kvm_arm_num_regs(vcpu);
>> +               if (copy_to_user(user_list, &reg_list, sizeof reg_list))
>> +                       return -EFAULT;
>> +               if (n < reg_list.n)
>> +                       return -E2BIG;
>> +               return kvm_arm_copy_reg_indices(vcpu, user_list->reg);
>> +       }
>> +       default:
>> +               return -EINVAL;
>> +       }
>> +}
>
> Your use of brackets with sizeof is inconsistent -- just always make it
> look like a function call.
>
>> diff --git a/arch/arm/kvm/emulate.c b/arch/arm/kvm/emulate.c
>> new file mode 100644
>> index 0000000..32e1172
>> --- /dev/null
>> +++ b/arch/arm/kvm/emulate.c
>> @@ -0,0 +1,149 @@
>> +/*
>> + * Copyright (C) 2012 - Virtual Open Systems and Columbia University
>> + * Author: Christoffer Dall <[e-mail]>
>> + *
>> + * 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 VCPU_NR_MODES 6
>> +#define REG_OFFSET(_reg) \
>> +       (offsetof(struct kvm_regs, _reg) / sizeof(u32))
>> +
>> +#define USR_REG_OFFSET(_num) REG_OFFSET(usr_regs.uregs[_num])
>> +
>> +static const unsigned long vcpu_reg_offsets[VCPU_NR_MODES][15] = {
>> +       /* USR/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), USR_REG_OFFSET(13), USR_REG_OFFSET(14),
>> +       },
>> +
>> +       /* 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[0]), /* 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 */
>> +       },
>> +
>> +       /* 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 */
>> +       },
>> +
>> +       /* 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 */
>> +       },
>> +
>> +       /* 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 */
>> +       },
>> +
>> +       /* 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 */
>> +       },
>> +};
>> +
>> +/*
>> + * Return a pointer to the register number valid in the current mode of
>> + * the virtual CPU.
>> + */
>> +u32 *vcpu_reg(struct kvm_vcpu *vcpu, u8 reg_num)
>> +{
>> +       u32 *reg_array = (u32 *)&vcpu->arch.regs;
>> +       u32 mode = *vcpu_cpsr(vcpu) & MODE_MASK;
>> +
>> +       switch (mode) {
>> +       case USR_MODE...SVC_MODE:
>> +               mode &= ~MODE32_BIT; /* 0 ... 3 */
>> +               break;
>> +
>> +       case ABT_MODE:
>> +               mode = 4;
>> +               break;
>> +
>> +       case UND_MODE:
>> +               mode = 5;
>> +               break;
>> +
>> +       case SYSTEM_MODE:
>> +               mode = 0;
>> +               break;
>> +
>> +       default:
>> +               BUG();
>> +       }
>> +
>> +       return reg_array + vcpu_reg_offsets[mode][reg_num];
>> +}
> ]
> Have some file-local #defines for those magic mode numbers.
>
>> +
>> +/*
>> + * Return the SPSR for the current mode of the virtual CPU.
>> + */
>> +u32 *vcpu_spsr(struct kvm_vcpu *vcpu)
>> +{
>> +       u32 mode = *vcpu_cpsr(vcpu) & MODE_MASK;
>> +       switch (mode) {
>> +       case SVC_MODE:
>> +               return &vcpu->arch.regs.svc_regs[2];
>> +       case ABT_MODE:
>> +               return &vcpu->arch.regs.abt_regs[2];
>> +       case UND_MODE:
>> +               return &vcpu->arch.regs.und_regs[2];
>> +       case IRQ_MODE:
>> +               return &vcpu->arch.regs.irq_regs[2];
>> +       case FIQ_MODE:
>> +               return &vcpu->arch.regs.fiq_regs[7];
>> +       default:
>> +               BUG();
>> +       }
>> +}
>
> Same here: have some #defines for the reg indices. They would also be
> useful to userspace when manipulating the vcpu state (currently there is
> just a comment in the header).
>


Thanks:

From cee1c41ab2022eab5df46ae43a95e32ad01020e7 Mon Sep 17 00:00:00 2001
From: Christoffer Dall <[e-mail]>
Date: Thu, 29 Nov 2012 17:33:04 -0500
Subject: [PATCH] KVM: ARM: Fixup KVM/ARM skeleton patch nits

This patch addresses comments from Will Deacon:
 - Make the kvm Makefile inclusion conditional
 - Create register index defines for struct kvm_regs banked regs
 - Support KVM_CAP_MAX_VCPUS and KVM_CAP_NR_VCPUS
 - Use defines for vcpu reg modes offsets

Cc: Will Deacon <[e-mail]>
Signed-off-by: Christoffer Dall <[e-mail]>
---
 Documentation/virtual/kvm/api.txt |    1 -
 arch/arm/Makefile                 |    2 +-
 arch/arm/include/asm/kvm_host.h   |    2 +-
 arch/arm/include/uapi/asm/kvm.h   |   24 ++++++++++++++++++++++++
 arch/arm/kvm/Kconfig              |    1 -
 arch/arm/kvm/Makefile             |    6 +++---
 arch/arm/kvm/arm.c                |   12 +++++++++---
 arch/arm/kvm/emulate.c            |   36 +++++++++++++++++++++---------------
 8 files changed, 59 insertions(+), 25 deletions(-)

 		USR_REG_OFFSET(6), USR_REG_OFFSET(7),
@@ -56,7 +62,7 @@ static const unsigned long
vcpu_reg_offsets[VCPU_NR_MODES][15] = {
 	},

 	/* IRQ Registers */
-	{
+	[VCPU_REG_OFFSET_IRQ] = {
 		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),
@@ -67,7 +73,7 @@ static const unsigned long
vcpu_reg_offsets[VCPU_NR_MODES][15] = {
 	},

 	/* SVC Registers */
-	{
+	[VCPU_REG_OFFSET_SVC] = {
 		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),
@@ -78,7 +84,7 @@ static const unsigned long
vcpu_reg_offsets[VCPU_NR_MODES][15] = {
 	},

 	/* ABT Registers */
-	{
+	[VCPU_REG_OFFSET_ABT] = {
 		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),
@@ -89,7 +95,7 @@ static const unsigned long
vcpu_reg_offsets[VCPU_NR_MODES][15] = {
 	},

 	/* UND Registers */
-	{
+	[VCPU_REG_OFFSET_UND] = {
 		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),
@@ -115,15 +121,15 @@ u32 *vcpu_reg(struct kvm_vcpu *vcpu, u8 reg_num)
 		break;

 	case ABT_MODE:
-		mode = 4;
+		mode = VCPU_REG_OFFSET_ABT;
 		break;

 	case UND_MODE:
-		mode = 5;
+		mode = VCPU_REG_OFFSET_UND;
 		break;

 	case SYSTEM_MODE:
-		mode = 0;
+		mode = VCPU_REG_OFFSET_USR;
 		break;

 	default:
@@ -141,15 +147,15 @@ u32 *vcpu_spsr(struct kvm_vcpu *vcpu)
 	u32 mode = *vcpu_cpsr(vcpu) & MODE_MASK;
 	switch (mode) {
 	case SVC_MODE:
-		return &vcpu->arch.regs.svc_regs[2];
+		return &vcpu->arch.regs.KVM_ARM_SVC_spsr;
 	case ABT_MODE:
-		return &vcpu->arch.regs.abt_regs[2];
+		return &vcpu->arch.regs.KVM_ARM_ABT_spsr;
 	case UND_MODE:
-		return &vcpu->arch.regs.und_regs[2];
+		return &vcpu->arch.regs.KVM_ARM_UND_spsr;
 	case IRQ_MODE:
-		return &vcpu->arch.regs.irq_regs[2];
+		return &vcpu->arch.regs.KVM_ARM_IRQ_spsr;
 	case FIQ_MODE:
-		return &vcpu->arch.regs.fiq_regs[7];
+		return &vcpu->arch.regs.KVM_ARM_FIQ_spsr;
 	default:
 		BUG();
 	}

Patch

diff --git a/Documentation/virtual/kvm/api.txt
b/Documentation/virtual/kvm/api.txt
index 35f6275..58c4345 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -1830,7 +1830,6 @@  The list of registers accessible using this
interface is identical to the
 list in 4.68.


-
 4.70 KVM_KVMCLOCK_CTRL

 Capability: KVM_CAP_KVMCLOCK_CTRL
diff --git a/arch/arm/Makefile b/arch/arm/Makefile
index 433becd..c87e089 100644
--- a/arch/arm/Makefile
+++ b/arch/arm/Makefile
@@ -252,12 +252,12 @@  core-$(CONFIG_FPE_NWFPE)	+= arch/arm/nwfpe/
 core-$(CONFIG_FPE_FASTFPE)	+= $(FASTFPE_OBJ)
 core-$(CONFIG_VFP)		+= arch/arm/vfp/
 core-$(CONFIG_XEN)		+= arch/arm/xen/
+core-$(CONFIG_KVM_ARM_HOST) 	+= arch/arm/kvm/

 # 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/net/
 core-y				+= arch/arm/crypto/
-core-y 				+= arch/arm/kvm/
 core-y				+= $(machdirs) $(platdirs)

 drivers-$(CONFIG_OPROFILE)      += arch/arm/oprofile/
diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
index 0a1a52b..ad1390f 100644
--- a/arch/arm/include/asm/kvm_host.h
+++ b/arch/arm/include/asm/kvm_host.h
@@ -93,7 +93,7 @@  struct kvm_vcpu_arch {
 	u32 midr;

 	/* Exception Information */
-	u32 hsr;		/* Hyp Syndrom Register */
+	u32 hsr;		/* Hyp Syndrome Register */
 	u32 hxfar;		/* Hyp Data/Inst Fault Address Register */
 	u32 hpfar;		/* Hyp IPA Fault Address Register */

diff --git a/arch/arm/include/uapi/asm/kvm.h b/arch/arm/include/uapi/asm/kvm.h
index b1c7871..09911a7 100644
--- a/arch/arm/include/uapi/asm/kvm.h
+++ b/arch/arm/include/uapi/asm/kvm.h
@@ -28,6 +28,30 @@ 
 #define KVM_REG_SIZE(id)						\
 	(1U << (((id) & KVM_REG_SIZE_MASK) >> KVM_REG_SIZE_SHIFT))

+/* Valid for svc_regs, abt_regs, und_regs, irq_regs in struct kvm_regs */
+#define KVM_ARM_SVC_sp		svc_regs[0]
+#define KVM_ARM_SVC_lr		svc_regs[1]
+#define KVM_ARM_SVC_spsr	svc_regs[2]
+#define KVM_ARM_ABT_sp		abt_regs[0]
+#define KVM_ARM_ABT_lr		abt_regs[1]
+#define KVM_ARM_ABT_spsr	abt_regs[2]
+#define KVM_ARM_UND_sp		und_regs[0]
+#define KVM_ARM_UND_lr		und_regs[1]
+#define KVM_ARM_UND_spsr	und_regs[2]
+#define KVM_ARM_IRQ_sp		irq_regs[0]
+#define KVM_ARM_IRQ_lr		irq_regs[1]
+#define KVM_ARM_IRQ_spsr	irq_regs[2]
+
+/* Valid only for fiq_regs in struct kvm_regs */
+#define KVM_ARM_FIQ_r8		fiq_regs[0]
+#define KVM_ARM_FIQ_r9		fiq_regs[1]
+#define KVM_ARM_FIQ_r10		fiq_regs[2]
+#define KVM_ARM_FIQ_fp		fiq_regs[3]
+#define KVM_ARM_FIQ_ip		fiq_regs[4]
+#define KVM_ARM_FIQ_sp		fiq_regs[5]
+#define KVM_ARM_FIQ_lr		fiq_regs[6]
+#define KVM_ARM_FIQ_spsr	fiq_regs[7]
+
 struct kvm_regs {
 	struct pt_regs usr_regs;/* R0_usr - R14_usr, PC, CPSR */
 	__u32 svc_regs[3];	/* SP_svc, LR_svc, SPSR_svc */
diff --git a/arch/arm/kvm/Kconfig b/arch/arm/kvm/Kconfig
index eaecb9f..60d3d2a 100644
--- a/arch/arm/kvm/Kconfig
+++ b/arch/arm/kvm/Kconfig
@@ -35,7 +35,6 @@  config KVM_ARM_HOST
 	bool "KVM host support for ARM cpus."
 	depends on KVM
 	depends on MMU
-	depends on CPU_V7 && ARM_VIRT_EXT
 	select	MMU_NOTIFIER
 	---help---
 	  Provides host support for ARM processors.
diff --git a/arch/arm/kvm/Makefile b/arch/arm/kvm/Makefile
index 7de231d..49919c4 100644
--- a/arch/arm/kvm/Makefile
+++ b/arch/arm/kvm/Makefile
@@ -16,8 +16,8 @@  AFLAGS_interrupts.o := -Wa,-march=armv7-a$(plus_virt)

 kvm-arm-y = $(addprefix ../../../virt/kvm/, kvm_main.o coalesced_mmio.o)

-obj-$(CONFIG_KVM_ARM_HOST) += kvm-arm.o init.o interrupts.o
-obj-$(CONFIG_KVM_ARM_HOST) += arm.o guest.o mmu.o emulate.o reset.o
-obj-$(CONFIG_KVM_ARM_HOST) += coproc.o coproc_a15.o mmio.o decode.o
+obj-y += kvm-arm.o init.o interrupts.o
+obj-y += arm.o guest.o mmu.o emulate.o reset.o
+obj-y += coproc.o coproc_a15.o mmio.o decode.o
 obj-$(CONFIG_KVM_ARM_VGIC) += vgic.o
 obj-$(CONFIG_KVM_ARM_TIMER) += timer.o
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index 508cf07..9827a3d 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -210,6 +210,12 @@  int kvm_dev_ioctl_check_extension(long ext)
 	case KVM_CAP_SET_DEVICE_ADDR:
 		r = 1;
 		break;
+	case KVM_CAP_NR_VCPUS:
+		r = num_online_cpus();
+		break;
+	case KVM_CAP_MAX_VCPUS:
+		r = KVM_MAX_VCPUS;
+		break;
 	default:
 		r = 0;
 		break;
@@ -834,7 +840,7 @@  long kvm_arch_vcpu_ioctl(struct file *filp,
 	case KVM_ARM_VCPU_INIT: {
 		struct kvm_vcpu_init init;

-		if (copy_from_user(&init, argp, sizeof init))
+		if (copy_from_user(&init, argp, sizeof(init)))
 			return -EFAULT;

 		return kvm_vcpu_set_target(vcpu, &init);
@@ -855,11 +861,11 @@  long kvm_arch_vcpu_ioctl(struct file *filp,
 		struct kvm_reg_list reg_list;
 		unsigned n;

-		if (copy_from_user(&reg_list, user_list, sizeof reg_list))
+		if (copy_from_user(&reg_list, user_list, sizeof(reg_list)))
 			return -EFAULT;
 		n = reg_list.n;
 		reg_list.n = kvm_arm_num_regs(vcpu);
-		if (copy_to_user(user_list, &reg_list, sizeof reg_list))
+		if (copy_to_user(user_list, &reg_list, sizeof(reg_list)))
 			return -EFAULT;
 		if (n < reg_list.n)
 			return -E2BIG;
diff --git a/arch/arm/kvm/emulate.c b/arch/arm/kvm/emulate.c
index 4e8a127..60e7ec0 100644
--- a/arch/arm/kvm/emulate.c
+++ b/arch/arm/kvm/emulate.c
@@ -25,7 +25,13 @@ 

 #include "trace.h"

-#define VCPU_NR_MODES 6
+#define VCPU_NR_MODES		6
+#define VCPU_REG_OFFSET_USR	0
+#define VCPU_REG_OFFSET_FIQ	1
+#define VCPU_REG_OFFSET_IRQ	2
+#define VCPU_REG_OFFSET_SVC	3
+#define VCPU_REG_OFFSET_ABT	4
+#define VCPU_REG_OFFSET_UND	5
 #define REG_OFFSET(_reg) \
 	(offsetof(struct kvm_regs, _reg) / sizeof(u32))

@@ -33,7 +39,7 @@ 

 static const unsigned long vcpu_reg_offsets[VCPU_NR_MODES][15] = {
 	/* USR/SYS Registers */
-	{
+	[VCPU_REG_OFFSET_USR] = {
 		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),
@@ -42,7 +48,7 @@  static const unsigned long
vcpu_reg_offsets[VCPU_NR_MODES][15] = {
 	},

 	/* FIQ Registers */
-	{
+	[VCPU_REG_OFFSET_FIQ] = {
 		USR_REG_OFFSET(0), USR_REG_OFFSET(1), USR_REG_OFFSET(2),
 		USR_REG_OFFSET(3), USR_REG_OFFSET(4), USR_REG_OFFSET(5),