On Thu, Dec 17, 2015 at 03:22:50PM +0800, Shannon Zhao 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 | > > >> The irq_num describes the PMU overflow interrupt number for the > >> specified > >> vcpu_index vcpu. This interrupt could be a PPI or SPI, but for one > >> VM the > >> interrupt type must be same for each vcpu. > > > > some formatting snafus that I expect come from pasting the text in an > > e-mail client. > > > >> > >> Errors: > >> -ENXIO: Getting or setting this attribute is not yet supported > > > > 'not yet supported' as in something we'll implement later, or as in you > > need to call this other function before you can access this state? > > > Since only when the group is not KVM_DEV_ARM_PMU_GRP_IRQ, it will return > -ENXIO. So what about this? > > "-ENXIO: Unsupported attribute group" > better,
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