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Commit 73891f72 authored by Victor Kamensky's avatar Victor Kamensky Committed by Christoffer Dall
Browse files

ARM: KVM: one_reg coproc set and get BE fixes 



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: default avatarVictor Kamensky <victor.kamensky@linaro.org>
Reviewed-by: default avatarChristoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
parent 27f194fd

arch/arm/kvm/coproc.c

+79 −9
Original line number Diff line number Diff line
@@ -44,6 +44,31 @@ 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 +707,23 @@ 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 +733,7 @@ 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, &params))

		return -ENOENT;
@@ -710,7 +742,15 @@ 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 +758,7 @@ 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, &params))

		return -ENOENT;
@@ -726,7 +766,16 @@ static int set_invariant_cp15(u64 id, void __user *uaddr) 
	if (!r)

		return -ENOENT;



	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 +1053,7 @@ 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 +1065,24 @@ 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 +1094,18 @@ 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)