Re: [PATCH 08/30] x86, kaiser: unmap kernel from userspace page tables (core patch)

[Dave Hansen]

On 11/20/2017 09:21 AM, Thomas Gleixner wrote:
>> +}
>> +
>>  static inline void native_set_p4d(p4d_t *p4dp, p4d_t p4d)
>>  {
>> +#if defined(CONFIG_KAISER) && !defined(CONFIG_X86_5LEVEL)
>> +	/*
>> +	 * set_pgd() does not get called when we are running
>> +	 * CONFIG_X86_5LEVEL=y.  So, just hack around it.  We
>> +	 * know here that we have a p4d but that it is really at
>> +	 * the top level of the page tables; it is really just a
>> +	 * pgd.
>> +	 */
>> +	/* Do we need to also populate the shadow p4d? */
>> +	if (is_userspace_pgd(p4dp))
>> +		native_get_shadow_p4d(p4dp)->pgd = p4d.pgd;
> native_get_shadow_p4d() is kinda confusing, as it suggest that we get the
> entry not the pointer to it. native_get_shadow_p4d_ptr() is what it
> actually wants to be, but a setter e.g. native_set_shadow...(), we also
> have set_pgd() would be more obvious I think.

How about "kernel_to_shadow_pgdp()"? ... and friends