Christoffer Dall <christoffer.d...@linaro.org> writes:
> On Wed, Jul 01, 2015 at 07:29:00PM +0100, Alex Bennée wrote:
>> This introduces a level of indirection for the debug registers. Instead
>> of using the sys_regs[] directly we store registers in a structure in
>> the vcpu. The new kvm_arm_reset_debug_ptr() sets the debug ptr to the
>> guest context.
>>
>> This also entails updating the sys_regs code to access this new
>> structure. New access function have been added for each set of debug
>> registers. The generic functions are still used for the few registers
>> stored in the main context.
>>
>> New access function pointers have been added to the sys_reg_desc
>> structure to support the GET/SET_ONE_REG ioctl operations.
>
> Why is this needed?
Previously I had a hacky:
if (r->access == trap_debug64)
return debug_get64(vcpu, r, reg, uaddr);
Which used the same offset information. Now we have a cleaner:
if (r->set)
return (r->set)(vcpu, r, reg, uaddr);
Which accesses the structure directly, as the trap functions do:
__u64 *r = &vcpu->arch.vcpu_debug_state.dbg_bvr[rd->reg];
if (copy_from_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
return -EFAULT;
return 0;
<snip>
>> +#if 0
>> +static int debug_set64(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
>> + const struct kvm_one_reg *reg, void __user *uaddr)
>> +{
>> + __u64 *r = (__u64 *) ((void * )&vcpu->arch.vcpu_debug_state + rd->reg);
>> + if (copy_from_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
>> + return -EFAULT;
>> + return 0;
>> +}
>> +
>> +static int debug_get64(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
>> + const struct kvm_one_reg *reg, void __user *uaddr)
>> +{
>> + __u64 *r = (__u64 *) ((void * )&vcpu->arch.vcpu_debug_state + rd->reg);
>> + if (copy_to_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
>> + return -EFAULT;
>> + return 0;
>> +}
>> +#endif
>> +
>
> what is this ifdef'ed block of code doing here?
Oops. Yeah looks like I missed removing that after I finished the
re-factor. These where the old get/set functions I used.
>
>> int kvm_arm_sys_reg_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg
>> *reg)
>> {
>> const struct sys_reg_desc *r;
>> @@ -1303,6 +1530,9 @@ int kvm_arm_sys_reg_get_reg(struct kvm_vcpu *vcpu,
>> const struct kvm_one_reg *reg
>> if (!r)
>> return get_invariant_sys_reg(reg->id, uaddr);
>>
>> + if (r->get)
>> + return (r->get)(vcpu, r, reg, uaddr);
>> +
>> return reg_to_user(uaddr, &vcpu_sys_reg(vcpu, r->reg), reg->id);
>> }
>>
>> @@ -1321,6 +1551,9 @@ int kvm_arm_sys_reg_set_reg(struct kvm_vcpu *vcpu,
>> const struct kvm_one_reg *reg
>> if (!r)
>> return set_invariant_sys_reg(reg->id, uaddr);
>>
>> + if (r->set)
>> + return (r->set)(vcpu, r, reg, uaddr);
>> +
>> return reg_from_user(&vcpu_sys_reg(vcpu, r->reg), uaddr, reg->id);
>> }
>>
>> diff --git a/arch/arm64/kvm/sys_regs.h b/arch/arm64/kvm/sys_regs.h
>> index d411e25..9265e7d 100644
>> --- a/arch/arm64/kvm/sys_regs.h
>> +++ b/arch/arm64/kvm/sys_regs.h
>> @@ -55,6 +55,12 @@ struct sys_reg_desc {
>>
>> /* Value (usually reset value) */
>> u64 val;
>> +
>> + /* Get/Set functions, fallback if NULL */
>
> Is this only meant for usersapce access or when should one use these?
Yes for GET/SET
>
>> + int (*get)(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
>> + const struct kvm_one_reg *reg, void __user *uaddr);
>> + int (*set)(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
>> + const struct kvm_one_reg *reg, void __user *uaddr);
>> };
>>
>> static inline void print_sys_reg_instr(const struct sys_reg_params *p)
>> --
>> 2.4.5
>>
--
Alex Bennée
--
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