Fix code that handles KVM_SET_ONE_REG, KVM_GET_ONE_REG ioctls to work in BE image. Before this fix get/set_one_reg functions worked correctly only in LE case - reg_from_user was taking 'void *' kernel address that actually could be target/source memory of either 4 bytes size or 8 bytes size, and code copied from/to user memory that could hold either 4 bytes register, 8 byte register or pair of 4 bytes registers.
In order to work in endian agnostic way reg_from_user to reg_to_user functions should copy register value only to kernel variable with size that matches register size. In few place where size mismatch existed fix issue on macro caller side.
Signed-off-by: Victor Kamensky victor.kamensky@linaro.org --- arch/arm/kvm/coproc.c | 84 +++++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 75 insertions(+), 9 deletions(-)
diff --git a/arch/arm/kvm/coproc.c b/arch/arm/kvm/coproc.c index c58a351..bcc9a0f 100644 --- a/arch/arm/kvm/coproc.c +++ b/arch/arm/kvm/coproc.c @@ -44,6 +44,30 @@ static u32 cache_levels; /* CSSELR values; used to index KVM_REG_ARM_DEMUX_ID_CCSIDR */ #define CSSELR_MAX 12
+/* + * kvm_vcpu_arch.cp15 holds cp15 registers as an array of u32, but some + * of cp15 registers can be viewed either as couple of two u32 registers + * or one u64 register. Current u64 register encoding is that least + * significant u32 word is followed by most significant u32 word. + */ +static inline void vcpu_cp15_reg64_set(struct kvm_vcpu *vcpu, + const struct coproc_reg *r, + u64 val) +{ + vcpu->arch.cp15[r->reg] = val & 0xffffffff; + vcpu->arch.cp15[r->reg + 1] = val >> 32; +} + +static inline u64 vcpu_cp15_reg64_get(struct kvm_vcpu *vcpu, + const struct coproc_reg *r) +{ + u64 val; + val = vcpu->arch.cp15[r->reg + 1]; + val = val << 32; + val = val | vcpu->arch.cp15[r->reg]; + return val; +} + int kvm_handle_cp10_id(struct kvm_vcpu *vcpu, struct kvm_run *run) { kvm_inject_undefined(vcpu); @@ -682,17 +706,23 @@ static struct coproc_reg invariant_cp15[] = { { CRn( 0), CRm( 0), Op1( 1), Op2( 7), is32, NULL, get_AIDR }, };
+/* + * Reads a register value from a userspace address to a kernel + * variable. Make sure that register size matches sizeof(*__val). + */ static int reg_from_user(void *val, const void __user *uaddr, u64 id) { - /* This Just Works because we are little endian. */ if (copy_from_user(val, uaddr, KVM_REG_SIZE(id)) != 0) return -EFAULT; return 0; }
+/* + * Writes a register value to a userspace address from a kernel variable. + * Make sure that register size matches sizeof(*__val). + */ static int reg_to_user(void __user *uaddr, const void *val, u64 id) { - /* This Just Works because we are little endian. */ if (copy_to_user(uaddr, val, KVM_REG_SIZE(id)) != 0) return -EFAULT; return 0; @@ -702,6 +732,7 @@ static int get_invariant_cp15(u64 id, void __user *uaddr) { struct coproc_params params; const struct coproc_reg *r; + int ret;
if (!index_to_params(id, ¶ms)) return -ENOENT; @@ -710,7 +741,14 @@ static int get_invariant_cp15(u64 id, void __user *uaddr) if (!r) return -ENOENT;
- return reg_to_user(uaddr, &r->val, id); + ret = -ENOENT; + if (KVM_REG_SIZE(id) == 4) { + u32 val = r->val; + ret = reg_to_user(uaddr, &val, id); + } else if (KVM_REG_SIZE(id) == 8) { + ret = reg_to_user(uaddr, &r->val, id); + } + return ret; }
static int set_invariant_cp15(u64 id, void __user *uaddr) @@ -718,7 +756,7 @@ static int set_invariant_cp15(u64 id, void __user *uaddr) struct coproc_params params; const struct coproc_reg *r; int err; - u64 val = 0; /* Make sure high bits are 0 for 32-bit regs */ + u64 val;
if (!index_to_params(id, ¶ms)) return -ENOENT; @@ -726,7 +764,15 @@ static int set_invariant_cp15(u64 id, void __user *uaddr) if (!r) return -ENOENT;
- err = reg_from_user(&val, uaddr, id); + err = -ENOENT; + if (KVM_REG_SIZE(id) == 4) { + u32 val32; + err = reg_from_user(&val32, uaddr, id); + if (!err) + val = val32; + } else if (KVM_REG_SIZE(id) == 8) { + err = reg_from_user(&val, uaddr, id); + } if (err) return err;
@@ -1004,6 +1050,7 @@ int kvm_arm_coproc_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg) { const struct coproc_reg *r; void __user *uaddr = (void __user *)(long)reg->addr; + int ret;
if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_DEMUX) return demux_c15_get(reg->id, uaddr); @@ -1015,14 +1062,23 @@ int kvm_arm_coproc_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg) if (!r) return get_invariant_cp15(reg->id, uaddr);
- /* Note: copies two regs if size is 64 bit. */ - return reg_to_user(uaddr, &vcpu->arch.cp15[r->reg], reg->id); + ret = -ENOENT; + if (KVM_REG_SIZE(reg->id) == 8) { + u64 val; + val = vcpu_cp15_reg64_get(vcpu, r); + ret = reg_to_user(uaddr, &val, reg->id); + } else if (KVM_REG_SIZE(reg->id) == 4) { + ret = reg_to_user(uaddr, &vcpu->arch.cp15[r->reg], reg->id); + } + + return ret; }
int kvm_arm_coproc_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg) { const struct coproc_reg *r; void __user *uaddr = (void __user *)(long)reg->addr; + int ret;
if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_DEMUX) return demux_c15_set(reg->id, uaddr); @@ -1034,8 +1090,18 @@ int kvm_arm_coproc_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg) if (!r) return set_invariant_cp15(reg->id, uaddr);
- /* Note: copies two regs if size is 64 bit */ - return reg_from_user(&vcpu->arch.cp15[r->reg], uaddr, reg->id); + ret = -ENOENT; + if (KVM_REG_SIZE(reg->id) == 8) { + u64 val; + ret = reg_from_user(&val, uaddr, reg->id); + if (!ret) { + vcpu_cp15_reg64_set(vcpu, r, val); + } + } else if (KVM_REG_SIZE(reg->id) == 4) { + ret = reg_from_user(&vcpu->arch.cp15[r->reg], uaddr, reg->id); + } + + return ret; }
static unsigned int num_demux_regs(void)