On 2015/12/17 16:33, Marc Zyngier wrote: > On Thu, 17 Dec 2015 15:22:50 +0800 > Shannon Zhao <zhaoshenglong@xxxxxxxxxx> wrote: > >> > >> > >> > On 2015/12/17 4:33, Christoffer Dall wrote: >>> > > On Wed, Dec 16, 2015 at 04:06:49PM +0800, Shannon Zhao wrote: >>>> > >> Hi, >>>> > >> >>>> > >> On 2015/12/16 15:31, Shannon Zhao wrote: >>>>>>>>>>> > >>>>>>>>> But in this case, you're returning an error if it is *not* initialized. >>>>>>>>>>> > >>>>>>>>> I understand that in that case you cannot return an interrupt number (-1 >>>>>>>>>>> > >>>>>>>>> would be weird), but returning -EBUSY feels even more weird. >>>>>>>>>>> > >>>>>>>>> >>>>>>>>>>> > >>>>>>>>> I'd settle for -ENOXIO, or something similar. Anyone having a better idea? >>>>>>>>>>> > >>>>>>>>> >>>>>>> > >>>>> ENXIO or ENODEV would be my choice too, and add that to the >>>>>>> > >>>>> Documentation clearly describing when this error code is used. >>>>>>> > >>>>> >>>>>>> > >>>>> By the way, why do you loop over all VCPUS to set the same value when >>>>>>> > >>>>> you can't do anything per VCPU anyway? It seems to me it's either a >>>>>>> > >>>>> per-VM property (that you can store on the VM data structure) or it's a >>>>>>> > >>>>> true per-VCPU property? >>>>> > >>> This is a per-VCPU property. PMU interrupt could be PPI or SPI. For PPI >>>>> > >>> the interrupt numbers are same for each vcpu, while for SPI they are >>>>> > >>> different, so it needs to set them separately. I planned to support both >>>>> > >>> PPI and SPI. I think I should add support for SPI at this moment and let >>>>> > >>> users (QEMU) to set these interrupts for each one. >>>> > >> >>>> > >> How about below vPMU Documentation? >>>> > >> >>>> > >> ARM Virtual Performance Monitor Unit (vPMU) >>>> > >> =========================================== >>>> > >> >>>> > >> Device types supported: >>>> > >> KVM_DEV_TYPE_ARM_PMU_V3 ARM Performance Monitor Unit v3 >>>> > >> >>>> > >> Instantiate one PMU instance for per VCPU through this API. >>>> > >> >>>> > >> Groups: >>>> > >> KVM_DEV_ARM_PMU_GRP_IRQ >>>> > >> Attributes: >>>> > >> The attr field of kvm_device_attr encodes two values: >>>> > >> bits: | 63 .... 32 | 31 .... 0 | >>>> > >> values: | vcpu_index | irq_num | >> > BTW, I change this Attribute to below format and pass vcpu_index through >> > this Attribute while pass irq_num through kvm_device_attr.addr. >> > Is it fine? >> > >> > bits: | 63 .... 32 | 31 .... 0 | >> > values: | reserved | vcpu_index | > Using the .addr field for something that is clearly not an address is > rather odd. Is there any prior usage of that field for something that > is not an address? I see this usage in vgic_attr_regs_access(). But if you prefer previous one, I'll use that. -- Shannon -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
