Hi Ayan, > On 2 Jul 2025, at 14:11, Ayan Kumar Halder <ayank...@amd.com> wrote: > > > On 01/07/2025 15:56, Hari Limaye wrote: >> >> Hi Ayan, >> > Hi Hari, >> >> Thank you for the review. I have just a couple of clarifications before I >> >> re-spin the series to address all the comments: >> >> > > - if ( flags & _PAGE_PRESENT ) >> >> > > + if ( (flags & _PAGE_PRESENT) && (MPUMAP_REGION_NOTFOUND == rc) ) >> >> > >> >> > Same question in this patch , why do we need to check for _PAGE_PRESENT. >> >> > Can't we just rely on MPUMAP_REGION_XXX ? >> >> The _PAGE_PRESENTflag indicates intent - whether the caller intends to create >> >> or remove a region. >> > If so, then I misunderstood the code. However, looking at > xen_pt_check_entry(), it seems _PAGE_PRESENTindicates if the page table entry > exists. If so, using _PAGE_PRESENTis not making sense to me atleast. May be > others can chime in.
But it seems to me that _PAGE_PRESENT is used in the MPU code in the same way as the MMU code, to check if the caller has intention to add/modify a region if it’s set, otherwise to delete it. I’m not sure why you say it’s different, can you point out which line in case, because I’ve had a look on xen_pt_check_entry but I didn’t get your point. Cheers, Luca
