Hi Michal, > On 14 Apr 2025, at 16:01, Orzel, Michal <michal.or...@amd.com> wrote: > > > > On 14/04/2025 16:50, Luca Fancellu wrote: >> Hi Michal, >> >>> On 14 Apr 2025, at 11:17, Orzel, Michal <michal.or...@amd.com> wrote: >>> >>> >>> >>> On 11/04/2025 16:56, Luca Fancellu wrote: >>>> From: Penny Zheng <penny.zh...@arm.com> >>>> >>>> Introduce pr_t typedef which is a structure having the prbar >>>> and prlar members, each being structured as the registers of >>>> the aarch64 armv8-r architecture. >>>> >>>> Introduce the array 'xen_mpumap' that will store a view of >>>> the content of the MPU regions. >>>> >>>> Introduce MAX_MPU_REGIONS macro that uses the value of >>>> NUM_MPU_REGIONS_MASK just for clarity, because using the >>>> latter as number of elements of the xen_mpumap array might >>>> be misleading. >>> What should be the size of this array? I thought NUM_MPU_REGIONS indicates >>> how >>> many regions there can be (i.e. 256) and this should be the size. Yet you >>> use >>> MASK for size which is odd. >> >> So the maximum number of regions for aarch64 armv8-r are 255, >> MPUIR_EL2.REGION is an >> 8 bit field advertising the number of region supported. > So there can be max 255 regions. Ok. > >> >> Is it better if I use just the below? >> >> #define MAX_MPU_REGIONS 255 > If there are 255 regions, what NUM_MPU_REGIONS macro is for which stores 256? > These two macros confuse me. Or is it that by your macro you want to denote > the > max region number? In that case, the macro should be named MAX_MPU_REGION_NR > or > alike.
I know, NUM_MPU_REGIONS should have a different name as it’s a bit misleading, ok I’ll name the macro I use here as MAX_MPU_REGION_NR. Cheers, Luca
