On 28.02.2022 11:20, Julien Grall wrote: > On 28/02/2022 10:10, Jan Beulich wrote: >> On 28.02.2022 10:55, Julien Grall wrote: >>> On 22/02/2022 15:22, Jan Beulich wrote: >>>> On 21.02.2022 11:22, Julien Grall wrote: >>>>> + /* >>>>> + * We cannot use set_fixmap() here. We use PMAP when there is no >>>>> direct map, >>>>> + * so map_pages_to_xen() called by set_fixmap() needs to map pages on >>>>> + * demand, which then calls pmap() again, resulting in a loop. >>>>> Modify the >>>>> + * PTEs directly instead. The same is true for pmap_unmap(). >>>>> + */ >>>>> + arch_pmap_map(slot, mfn); >>>> >>>> I'm less certain here, but like above I'm under the impression >>>> that this comment may no longer be accurate. >>> >>> This comment is still accurate for Arm. I also expect it to be accurate >>> for all architectures because set_fixmap() is likely going to be >>> implemented with generic PT helpers. >>> >>> So I think it makes sense to keep it in common code. This explains why >>> we are calling arch_pmap_map() rather than set_fixmap() directly. >> >> I guess I was rather after "when there is no direct map" alluding to the >> planned removal of it on x86. > It is one way to interpret it. The other way is that pmap will be used > when the directmap is not yet in place. > > But I guess I could be less specific and refers to the fact the domain > page infrastructure is not yet setup. Would that be better for you?
That or simply add "(yet)" to what is there. Jan
