Thread (82 messages) 82 messages, 12 authors, 2012-10-08
STALE4984d

[PATCH 06/15] KVM: ARM: Initial skeleton to compile KVM support

From: Will Deacon <hidden>
Date: 2012-09-25 15:20:55
Also in: kvm

On Sat, Sep 15, 2012 at 04:35:08PM +0100, 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.

?Nothing to see here. Move along, move along..."
[...]
quoted hunk ↗ jump to hunk
diff --git a/arch/arm/include/asm/kvm.h b/arch/arm/include/asm/kvm.h
new file mode 100644
index 0000000..a13b582
--- /dev/null
+++ b/arch/arm/include/asm/kvm.h
@@ -0,0 +1,88 @@
+/*
+ * Copyright (C) 2012 - Virtual Open Systems and Columbia University
+ * Author: Christoffer Dall <c.dall@virtualopensystems.com>
+ *
+ * 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
+
+#define KVM_REG_SIZE(id)                                               \
+       (1U << (((id) & KVM_REG_SIZE_MASK) >> KVM_REG_SIZE_SHIFT))
+
+struct kvm_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 */
+};
+
+/* Supported Processor Types */
+#define KVM_ARM_TARGET_CORTEX_A15      (0xC0F)
So there's this define...
quoted hunk ↗ jump to hunk
diff --git a/arch/arm/include/asm/kvm_arm.h b/arch/arm/include/asm/kvm_arm.h
new file mode 100644
index 0000000..2f9d28e
--- /dev/null
+++ b/arch/arm/include/asm/kvm_arm.h
@@ -0,0 +1,28 @@
+/*
+ * Copyright (C) 2012 - Virtual Open Systems and Columbia University
+ * Author: Christoffer Dall <c.dall@virtualopensystems.com>
+ *
+ * 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_ARM_H__
+#define __ARM_KVM_ARM_H__
+
+/* Supported Processor Types */
+#define CORTEX_A15     (0xC0F)
... and then this one. Do we really need both?
+/* Multiprocessor Affinity Register */
+#define MPIDR_CPUID    (0x3 << 0)
I'm fairly sure we already have code under arch/arm/ for dealing with the
mpidr. Let's re-use that rather than reinventing it here.
quoted hunk ↗ jump to hunk
diff --git a/arch/arm/include/asm/kvm_asm.h b/arch/arm/include/asm/kvm_asm.h
new file mode 100644
index 0000000..44591f9
--- /dev/null
+++ b/arch/arm/include/asm/kvm_asm.h
@@ -0,0 +1,30 @@
+/*
+ * Copyright (C) 2012 - Virtual Open Systems and Columbia University
+ * Author: Christoffer Dall <c.dall@virtualopensystems.com>
+ *
+ * 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
Again, you have these defines (which look more suited to an enum type), but
later (in kvm_host.h) you have:
+#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
Why the noise?
quoted hunk ↗ jump to hunk
diff --git a/arch/arm/include/asm/kvm_emulate.h b/arch/arm/include/asm/kvm_emulate.h
new file mode 100644
index 0000000..9e29335
--- /dev/null
+++ b/arch/arm/include/asm/kvm_emulate.h
@@ -0,0 +1,108 @@
+/*
+ * Copyright (C) 2012 - Virtual Open Systems and Columbia University
+ * Author: Christoffer Dall <c.dall@virtualopensystems.com>
+ *
+ * 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 u8 __vcpu_mode(u32 cpsr)
+{
+       u8 modes_table[32] = {
+               0xf, 0xf, 0xf, 0xf, 0xf, 0xf, 0xf, 0xf,
+               0xf, 0xf, 0xf, 0xf, 0xf, 0xf, 0xf, 0xf,
+               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 */
+       };
These MODE_* definitions sound like our *_MODE definitions... except they're
not. It would probably be far more readable as a switch, but at least change
the name of those things!
+static inline enum vcpu_mode vcpu_mode(struct kvm_vcpu *vcpu)
+{
+       u8 mode = __vcpu_mode(vcpu->arch.regs.cpsr);
+       BUG_ON(mode == 0xf);
+       return mode;
+}
I noticed that you have a fair few BUG_ONs throughout the series. Fair
enough, but for hyp code is that really the right thing to do? Killing the
guest could make more sense, perhaps?
+static inline u32 *vcpu_pc(struct kvm_vcpu *vcpu)
+{
+       return vcpu_reg(vcpu, 15);
+}
If you stick a struct pt_regs into struct kvm_regs, you could reuse ARM_pc
here etc.
quoted hunk ↗ jump to hunk
diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
new file mode 100644
index 0000000..24959f4
--- /dev/null
+++ b/arch/arm/include/asm/kvm_host.h
@@ -0,0 +1,172 @@
+/*
+ * Copyright (C) 2012 - Virtual Open Systems and Columbia University
+ * Author: Christoffer Dall <c.dall@virtualopensystems.com>
+ *
+ * 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>
+
+#define KVM_MAX_VCPUS 4
NR_CPUS?
+#define KVM_MEMORY_SLOTS 32
+#define KVM_PRIVATE_MEM_SLOTS 4
+#define KVM_COALESCED_MMIO_PAGE_OFFSET 1
+
+#define NUM_FEATURES 0
Ha! No idea what that means, but hopefully there's less code to review
because of it :)
+
+/* 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 {
+       /* The VMID generation used for the virt. memory system */
+       u64    vmid_gen;
+       u32    vmid;
+
+       /* 1-level 2nd stage table and lock */
+       spinlock_t pgd_lock;
+       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
+
+#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];
+};
+
+/*
+ * 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
+};
So the need for this enum is for indexing the array of modes, right? But
accesses to that array are already hidden behind an accessor function from
what I can tell, so I'd rather the arithmetic from cpsr -> index was
restricted to that function and the rest of the code just passed either the
raw mode or the full cpsr around.
quoted hunk ↗ jump to hunk
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
new file mode 100644
index 0000000..fd6fa9b
--- /dev/null
+++ b/arch/arm/kvm/arm.c
@@ -0,0 +1,345 @@
+/*
+ * Copyright (C) 2012 - Virtual Open Systems and Columbia University
+ * Author: Christoffer Dall <c.dall@virtualopensystems.com>
+ *
+ * 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>
+#include <asm/cputype.h>
+
+#ifdef REQUIRES_VIRT
+__asm__(".arch_extension       virt");
+#endif
+
+int kvm_arch_hardware_enable(void *garbage)
+{
+       return 0;
+}
+
+int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu)
+{
+       return kvm_vcpu_exiting_guest_mode(vcpu) == IN_GUEST_MODE;
+}
+
+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:
+       case KVM_CAP_ONE_REG:
+               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_all(struct kvm *kvm)
+{
+}
+
+void kvm_arch_flush_shadow_memslot(struct kvm *kvm,
+                                  struct kvm_memory_slot *slot)
+{
+}
+
+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 __attribute_const__ kvm_target_cpu(void)
+{
+       unsigned int midr;
+
+       midr = read_cpuid_id();
+       switch ((midr >> 4) & 0xfff) {
+       case KVM_ARM_TARGET_CORTEX_A15:
+               return KVM_ARM_TARGET_CORTEX_A15;
I have this code already in perf_event.c. Can we move it somewhere common
and share it? You should also check that the implementor field is 0x41.
+       default:
+               return -EINVAL;
+       }
+}
+
+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)
+{
+       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);
kvm_reg_list sounds like it could be done using a regset instead.
quoted hunk ↗ jump to hunk
diff --git a/arch/arm/kvm/emulate.c b/arch/arm/kvm/emulate.c
new file mode 100644
index 0000000..690bbb3
--- /dev/null
+++ b/arch/arm/kvm/emulate.c
@@ -0,0 +1,127 @@
+/*
+ * Copyright (C) 2012 - Virtual Open Systems and Columbia University
+ * Author: Christoffer Dall <c.dall@virtualopensystems.com>
+ *
+ * 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_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);
Again, BUG_ON seems a bit OTT here. Also, this is where the mode => idx
calculation should happen.
quoted hunk ↗ jump to hunk
+       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..3e38c95
--- /dev/null
+++ b/arch/arm/kvm/exports.c
@@ -0,0 +1,21 @@
+/*
+ * Copyright (C) 2012 - Virtual Open Systems and Columbia University
+ * Author: Christoffer Dall <c.dall@virtualopensystems.com>
+ *
+ * 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>
+
+EXPORT_SYMBOL_GPL(smp_send_reschedule);
Erm...

We already have arch/arm/kernel/armksyms.c for exports -- please use that.
However, exporting such low-level operations sounds like a bad idea. How
realistic is kvm-as-a-module on ARM anyway?
quoted hunk ↗ jump to hunk
diff --git a/arch/arm/kvm/guest.c b/arch/arm/kvm/guest.c
new file mode 100644
index 0000000..19a5389
--- /dev/null
+++ b/arch/arm/kvm/guest.c
@@ -0,0 +1,211 @@
+/*
+ * Copyright (C) 2012 - Virtual Open Systems and Columbia University
+ * Author: Christoffer Dall <c.dall@virtualopensystems.com>
+ *
+ * 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.h>
+#include <asm/kvm_asm.h>
+#include <asm/kvm_emulate.h>
+
+#define VM_STAT(x) { #x, offsetof(struct kvm, stat.x), KVM_STAT_VM }
+#define VCPU_STAT(x) { #x, offsetof(struct kvm_vcpu, stat.x), KVM_STAT_VCPU }
+
+struct kvm_stats_debugfs_item debugfs_entries[] = {
+       { NULL }
+};
+
+int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu)
+{
+       return 0;
+}
+
+static u64 core_reg_offset_from_id(u64 id)
+{
+       return id & ~(KVM_REG_ARCH_MASK | KVM_REG_SIZE_MASK | KVM_REG_ARM_CORE);
+}
+
+static int get_core_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
+{
+       u32 __user *uaddr = (u32 __user *)(long)reg->addr;
+       struct kvm_regs *regs = &vcpu->arch.regs;
+       u64 off;
+
+       if (KVM_REG_SIZE(reg->id) != 4)
+               return -ENOENT;
+
+       /* Our ID is an index into the kvm_regs struct. */
+       off = core_reg_offset_from_id(reg->id);
+       if (off >= sizeof(*regs) / KVM_REG_SIZE(reg->id))
+               return -ENOENT;
+
+       return put_user(((u32 *)regs)[off], uaddr);
+}
+
+static int set_core_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
+{
+       u32 __user *uaddr = (u32 __user *)(long)reg->addr;
+       struct kvm_regs *regs = &vcpu->arch.regs;
+       u64 off, val;
+
+       if (KVM_REG_SIZE(reg->id) != 4)
+               return -ENOENT;
+
+       /* Our ID is an index into the kvm_regs struct. */
+       off = core_reg_offset_from_id(reg->id);
+       if (off >= sizeof(*regs) / KVM_REG_SIZE(reg->id))
+               return -ENOENT;
+
+       if (get_user(val, uaddr) != 0)
+               return -EFAULT;
+
+       if (off == KVM_REG_ARM_CORE_REG(cpsr)) {
+               if (__vcpu_mode(val) == 0xf)
+                       return -EINVAL;
+       }
+
+       ((u32 *)regs)[off] = val;
+       return 0;
+}
+
+int kvm_arch_vcpu_ioctl_get_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs)
+{
+       return -EINVAL;
+}
+
+int kvm_arch_vcpu_ioctl_set_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs)
+{
+       return -EINVAL;
+}
Again, all looks like this should be implemented using regsets from what I
can tell.
quoted hunk ↗ jump to hunk
diff --git a/arch/arm/kvm/reset.c b/arch/arm/kvm/reset.c
new file mode 100644
index 0000000..290a13d
--- /dev/null
+++ b/arch/arm/kvm/reset.c
@@ -0,0 +1,74 @@
+/*
+ * Copyright (C) 2012 - Virtual Open Systems and Columbia University
+ * Author: Christoffer Dall <c.dall@virtualopensystems.com>
+ *
+ * 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/compiler.h>
+#include <linux/errno.h>
+#include <linux/sched.h>
+#include <linux/kvm_host.h>
+#include <linux/kvm.h>
+
+#include <asm/unified.h>
+#include <asm/ptrace.h>
+#include <asm/cputype.h>
+#include <asm/kvm_arm.h>
+#include <asm/kvm_coproc.h>
+
+/******************************************************************************
+ * Cortex-A15 Reset Values
+ */
+
+static const int a15_max_cpu_idx = 3;
+
+static struct kvm_regs a15_regs_reset = {
+       .cpsr = SVC_MODE | PSR_A_BIT | PSR_I_BIT | PSR_F_BIT,
+};
+
+
+/*******************************************************************************
+ * Exported reset function
+ */
+
+/**
+ * kvm_reset_vcpu - sets core registers and cp15 registers to reset value
+ * @vcpu: The VCPU pointer
+ *
+ * This function finds the right table above and sets the registers on the
+ * virtual CPU struct to their architectually defined reset values.
+ */
+int kvm_reset_vcpu(struct kvm_vcpu *vcpu)
+{
+       struct kvm_regs *cpu_reset;
+
+       switch (vcpu->arch.target) {
+       case KVM_ARM_TARGET_CORTEX_A15:
+               if (vcpu->vcpu_id > a15_max_cpu_idx)
+                       return -EINVAL;
+               cpu_reset = &a15_regs_reset;
+               vcpu->arch.midr = read_cpuid_id();
+               break;
+       default:
+               return -ENODEV;
+       }
+
+       /* Reset core registers */
+       memcpy(&vcpu->arch.regs, cpu_reset, sizeof(vcpu->arch.regs));
+
+       /* Reset CP15 registers */
+       kvm_reset_coprocs(vcpu);
+
+       return 0;
+}
This is a nice way to plug in new CPUs but the way the rest of the code is
currently written, all the ARMv7 and Cortex-A15 code is merged together. I
*strongly* suggest you isolate this from the start, as it will help you see
what is architected and what is implementation-specific.

Will
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