On 29 November 2012 18:12, Marc Zyngier <marc.zyngier@xxxxxxx> wrote: > On 29/11/12 17:36, Peter Maydell wrote: >> On 29 November 2012 17:16, Marc Zyngier <marc.zyngier@xxxxxxx> wrote: >>> Userspace needs to know how big the CPU and distrbutor interfaces >>> are in order to map them at non overlapping addresses. >> >> As it happens, QEMU doesn't -- we assume that if we asked for >> an A15 with a GIC then you give us a GIC compliant with the A15 TRM >> and the GIC v2 spec, which lays down how big the CPU and distributor >> memory regions must be. I'm not convinced the kernel needs to >> include in its userspace-facing headers definitions which are >> purely properties of the hardware. > > It may not be strictly required, but it definitely helps. Also, if I > follow your logic, we shouldn't have two different ranges for the > distributor and the CPU interface: the A15 TRM already specifies their > relative positions. Arguably so, yes -- this is how the hardware does it (there is one set of config signals setting PERIPHBASE, not separate config for cpu and dist i/f addresses. However it turns out to be convenient for userspace to do it this way round, so I'm not in favour of reworking that at this point :-) -- PMM _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/cucslists/listinfo/kvmarm
