Re: [RFC][PATCH 05/10] x86/mm: do not auto-massage page protections

2018-02-22 Thread Dave Hansen 
On 02/22/2018 01:46 PM, Nadav Amit wrote:
>>
>> +static inline pgprotval_t check_pgprot(pgprot_t pgprot)
>> +{
>> +pgprotval_t massaged_val = massage_pgprot(pgprot);
>> +
>> +WARN_ONCE(pgprot_val(pgprot) != massaged_val,
>> +  "attempted to set unsupported pgprot: %016lx "
>> +  "bits: %016lx supported: %016lx\n",
>> +  pgprot_val(pgprot),
>> +  pgprot_val(pgprot) ^ massaged_val,
>> +  __supported_pte_mask);
> Perhaps use VM_WARN_ONCE instead to avoid any overhead on production
> systems?

Sounds sane enough.  I'll change it.

Re: [RFC][PATCH 05/10] x86/mm: do not auto-massage page protections

2018-02-22 Thread Nadav Amit 
Dave Hansen  wrote:

> 
> From: Dave Hansen 
> 
> 
> +static inline pgprotval_t check_pgprot(pgprot_t pgprot)
> +{
> + pgprotval_t massaged_val = massage_pgprot(pgprot);
> +
> + WARN_ONCE(pgprot_val(pgprot) != massaged_val,
> +   "attempted to set unsupported pgprot: %016lx "
> +   "bits: %016lx supported: %016lx\n",
> +   pgprot_val(pgprot),
> +   pgprot_val(pgprot) ^ massaged_val,
> +   __supported_pte_mask);

Perhaps use VM_WARN_ONCE instead to avoid any overhead on production
systems?