On Wed, May 11 2022 at 09:02, Peter Zijlstra wrote:
> On Wed, May 11, 2022 at 05:27:45AM +0300, Kirill A. Shutemov wrote:
>
>> +#define LAM_NONE 0
>> +#define LAM_U57 1
>> +#define LAM_U48 2
>
>> +#define X86_THREAD_LAM_U48 0x1
>> +#define X86_THREAD_LAM_U57 0x2
>
> Seriously pick an order and stick with it. I would suggest keeping the
> hardware order and then you can do:
>
>> +static inline unsigned long lam_to_cr3(u8 lam)
>> +{
>
> return (lam & 0x3) << X86_CR3_LAM_U57;
This "works" because the hardware ignores LAM_U48 if LAM_U57 is set, but
I'd rather make that exclusive in the prctl() as setting both does not
make any sense.
> I'm still not liking LAM(e), I'm thikning it's going to create more
> problems than it solves.
Isn't that true for most new hardware features?
Thanks,
tglx
