On Fri, Apr 26, 2013 at 12:21 AM, Christoffer Dall <cdall@xxxxxxxxxxxxxxx> wrote: > On Apr 25, 2013, at 11:20 AM, Peter Maydell <peter.maydell@xxxxxxxxxx> wrote: > >> On 25 April 2013 19:04, Christoffer Dall <cdall@xxxxxxxxxxxxxxx> wrote: >>> I prefer not hard-coding this stuff in the kernel, but let user space >>> decide this. If we have good technical arguments not to do that (such >>> as knowing that this is always defined per-core and not for an SoC >>> (ARM guys?) then at least the patch should lookup the target processor >>> and set the irq number accordingly. >> >> Well, this is all implementation-defined. The ARM ARM mandates >> that the generic timers deliver a PPI, and that it must be the >> same PPI for all processors in an MP implementation, but not which >> PPI. The A15 and A7 happen to both be hardwired to ID27. You could >> in theory design a core which let the SoC configure the virtual >> timer ID (or let the guest arbitrarily program it, for that >> matter, I suppose), though I'm not sure why you'd want to. >> >> I think I'd take the simple approach of saying "the timer PPI >> is a fixed property of the guest CPU" unless somebody actually >> builds something where it isn't fixed... (for that CPU we >> could then define it as a feature argument to KVM_ARM_VCPU_INIT). >> > > Ok, let's not bother with user space injection then, but instead of > hard defaulting to two specific cores, please make a switch statement > on the target CPU and log an error on init if it's an unknown core. I agree about determing guest ppi from KVM_TARGET_xxxx in kvm_timer_vcpu_init() but kvm_timer_vcpu_init() is called much before kvm_vcpu_set_target() so in kvm_timer_vcpu_init() we have vcpu->arch.target = -1 (unknown). To handle this issue, we need to determine vcpu timer irq number when we inject the timer irq first timer for that vcpu. > _______________________________________________ > kvmarm mailing list > kvmarm@xxxxxxxxxxxxxxxxxxxxx > https://lists.cs.columbia.edu/cucslists/listinfo/kvmarm -Anup _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/cucslists/listinfo/kvmarm
