On 28.10.2024 18:38, Ayan Kumar Halder wrote: > On 28/10/2024 15:01, Jan Beulich wrote: >> On 28.10.2024 15:39, Ayan Kumar Halder wrote: >>> On 28/10/2024 12:55, Jan Beulich wrote: >>>> On 28.10.2024 13:45, Ayan Kumar Halder wrote: >>>>> --- a/xen/arch/Kconfig >>>>> +++ b/xen/arch/Kconfig >>>>> @@ -6,11 +6,13 @@ config PHYS_ADDR_T_32 >>>>> >>>>> config NR_CPUS >>>>> int "Maximum number of CPUs" >>>>> + range 1 1 if ARM && MPU >>>>> range 1 16383 >>>>> default "256" if X86 >>>>> default "8" if ARM && RCAR3 >>>>> default "4" if ARM && QEMU >>>>> default "4" if ARM && MPSOC >>>>> + default "1" if ARM && MPU >>>>> default "128" if ARM >>>>> help >>>>> Controls the build-time size of various arrays and bitmaps >>>> I'm afraid I can't easily tell whether MPU can be used together with any of >>>> RCAR3, QEMU, or MPSOC. If it can, the new default line would need to move >>>> up, as it's the first one that has a match on its condition which is being >>>> used. >>> MPU cannot be used with any of the existing platforms. >> That is - qemu can't emulate such an environment, i.e. even QEMU and MPU >> don't go together? > > Qemu has support for Aarch32 MPU at EL2 and EL1 (ie R52). As far as I am > aware, there is no support for Aarch64 MPU in Qemu (ie R82). > > Even for R52, I could not get the upstream Qemu working (emulating some > Arm reference platform). > > I could get the Xilinx fork of Qemu (https://github.com/Xilinx/qemu) > working which emulates AMD's SoC using R52. > > However, this should not impact the current patch. There is no Qemu in > xen/arch/arm/platforms/*.
Aiui that's not relevant. There is a QEMU item in xen/arch/arm/platforms/Kconfig. I continue to fail to see why that couldn't be selected together with MPU. Yet if it can be, you'd end up with a default of 4, not 1, if it actually _is_ selected. Alternatively QEMU (and maybe also RCAR3 and MPSOC) need to be mutually exclusive with MPU. Hmm, looks like that's already the case, by patch 2 suppressing the "Platform Support" prompt. While that looks fragile to me, I'm sorry for the noise then. Jan
