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linux-next/arch/arm/kvm/guest.c
Will Deacon bd218bce92 KVM: ARM/arm64: return -EFAULT if copy_from_user fails in set_timer_reg
We currently return the number of bytes not copied if set_timer_reg
fails, which is almost certainly not what userspace would like.

This patch returns -EFAULT instead.

Cc: Christoffer Dall <christoffer.dall@linaro.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2014-08-27 22:49:45 +02:00

337 lines
7.8 KiB
C

/*
* 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/cputype.h>
#include <asm/uaccess.h>
#include <asm/kvm.h>
#include <asm/kvm_asm.h>
#include <asm/kvm_emulate.h>
#include <asm/kvm_coproc.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)
{
vcpu->arch.hcr = HCR_GUEST_MASK;
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(usr_regs.ARM_cpsr)) {
unsigned long mode = val & MODE_MASK;
switch (mode) {
case USR_MODE:
case FIQ_MODE:
case IRQ_MODE:
case SVC_MODE:
case ABT_MODE:
case UND_MODE:
break;
default:
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;
}
#ifndef CONFIG_KVM_ARM_TIMER
#define NUM_TIMER_REGS 0
static int copy_timer_indices(struct kvm_vcpu *vcpu, u64 __user *uindices)
{
return 0;
}
static bool is_timer_reg(u64 index)
{
return false;
}
#else
#define NUM_TIMER_REGS 3
static bool is_timer_reg(u64 index)
{
switch (index) {
case KVM_REG_ARM_TIMER_CTL:
case KVM_REG_ARM_TIMER_CNT:
case KVM_REG_ARM_TIMER_CVAL:
return true;
}
return false;
}
static int copy_timer_indices(struct kvm_vcpu *vcpu, u64 __user *uindices)
{
if (put_user(KVM_REG_ARM_TIMER_CTL, uindices))
return -EFAULT;
uindices++;
if (put_user(KVM_REG_ARM_TIMER_CNT, uindices))
return -EFAULT;
uindices++;
if (put_user(KVM_REG_ARM_TIMER_CVAL, uindices))
return -EFAULT;
return 0;
}
#endif
static int set_timer_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
{
void __user *uaddr = (void __user *)(long)reg->addr;
u64 val;
int ret;
ret = copy_from_user(&val, uaddr, KVM_REG_SIZE(reg->id));
if (ret != 0)
return -EFAULT;
return kvm_arm_timer_set_reg(vcpu, reg->id, val);
}
static int get_timer_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
{
void __user *uaddr = (void __user *)(long)reg->addr;
u64 val;
val = kvm_arm_timer_get_reg(vcpu, reg->id);
return copy_to_user(uaddr, &val, KVM_REG_SIZE(reg->id));
}
static unsigned long num_core_regs(void)
{
return sizeof(struct kvm_regs) / sizeof(u32);
}
/**
* kvm_arm_num_regs - how many registers do we present via KVM_GET_ONE_REG
*
* This is for all registers.
*/
unsigned long kvm_arm_num_regs(struct kvm_vcpu *vcpu)
{
return num_core_regs() + kvm_arm_num_coproc_regs(vcpu)
+ NUM_TIMER_REGS;
}
/**
* kvm_arm_copy_reg_indices - get indices of all registers.
*
* We do core registers right here, then we apppend coproc regs.
*/
int kvm_arm_copy_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices)
{
unsigned int i;
const u64 core_reg = KVM_REG_ARM | KVM_REG_SIZE_U32 | KVM_REG_ARM_CORE;
int ret;
for (i = 0; i < sizeof(struct kvm_regs)/sizeof(u32); i++) {
if (put_user(core_reg | i, uindices))
return -EFAULT;
uindices++;
}
ret = copy_timer_indices(vcpu, uindices);
if (ret)
return ret;
uindices += NUM_TIMER_REGS;
return kvm_arm_copy_coproc_indices(vcpu, uindices);
}
int kvm_arm_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
{
/* We currently use nothing arch-specific in upper 32 bits */
if ((reg->id & ~KVM_REG_SIZE_MASK) >> 32 != KVM_REG_ARM >> 32)
return -EINVAL;
/* Register group 16 means we want a core register. */
if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_CORE)
return get_core_reg(vcpu, reg);
if (is_timer_reg(reg->id))
return get_timer_reg(vcpu, reg);
return kvm_arm_coproc_get_reg(vcpu, reg);
}
int kvm_arm_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
{
/* We currently use nothing arch-specific in upper 32 bits */
if ((reg->id & ~KVM_REG_SIZE_MASK) >> 32 != KVM_REG_ARM >> 32)
return -EINVAL;
/* Register group 16 means we set a core register. */
if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_CORE)
return set_core_reg(vcpu, reg);
if (is_timer_reg(reg->id))
return set_timer_reg(vcpu, reg);
return kvm_arm_coproc_set_reg(vcpu, reg);
}
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 __attribute_const__ kvm_target_cpu(void)
{
switch (read_cpuid_part()) {
case ARM_CPU_PART_CORTEX_A7:
return KVM_ARM_TARGET_CORTEX_A7;
case ARM_CPU_PART_CORTEX_A15:
return KVM_ARM_TARGET_CORTEX_A15;
default:
return -EINVAL;
}
}
int kvm_vcpu_set_target(struct kvm_vcpu *vcpu,
const struct kvm_vcpu_init *init)
{
unsigned int i;
/* We can only cope with guest==host and only on A15/A7 (for now). */
if (init->target != kvm_target_cpu())
return -EINVAL;
vcpu->arch.target = init->target;
bitmap_zero(vcpu->arch.features, KVM_VCPU_MAX_FEATURES);
/* -ENOENT for unknown features, -EINVAL for invalid combinations. */
for (i = 0; i < sizeof(init->features) * 8; i++) {
if (test_bit(i, (void *)init->features)) {
if (i >= KVM_VCPU_MAX_FEATURES)
return -ENOENT;
set_bit(i, vcpu->arch.features);
}
}
/* Now we know what it is, we can reset it. */
return kvm_reset_vcpu(vcpu);
}
int kvm_vcpu_preferred_target(struct kvm_vcpu_init *init)
{
int target = kvm_target_cpu();
if (target < 0)
return -ENODEV;
memset(init, 0, sizeof(*init));
/*
* For now, we don't return any features.
* In future, we might use features to return target
* specific features available for the preferred
* target type.
*/
init->target = (__u32)target;
return 0;
}
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;
}