Re: [PATCH v17] x86/split_lock: Enable split lock detection by kernel

[Thomas Gleixner]

Sean Christopherson <sean.j.christopherson@xxxxxxxxx> writes:

> On Sun, Jan 26, 2020 at 12:05:35PM -0800, Luck, Tony wrote:
>
> ...
>
>> +bool handle_user_split_lock(struct pt_regs *regs, long error_code)
>
> No reason to take the error code unless there's a plan to use it.
>
>> +{
>> +	if ((regs->flags & X86_EFLAGS_AC) || sld_state == sld_fatal)
>> +		return false;
>
> Any objection to moving the EFLAGS.AC up to do_alignment_check()?  And
> take "unsigned long rip" instead of @regs?
>
> That would allow KVM to reuse handle_user_split_lock() for guest faults
> without any changes (other than exporting).
>
> E.g. do_alignment_check() becomes:
>
> 	if (!(regs->flags & X86_EFLAGS_AC) && handle_user_split_lock(regs->ip))
> 		return;

No objections.

Thanks,

        tglx