On 06/07/2015 12:37, Christoffer Dall wrote: > I don't view it as 'the kernel requires this' but as 'the kernel will > not complain with arbitrary error code if you set the devid flag' > capability, and it's up to userspace (as usual) to provide the correct > arguments for things to work, and up to the kernel to ensure we don't > crash the system etc. > > Thus, if you want to advertise it as a capability, I would rather call > it KVM_CAP_MSI_DEVID. I agree. Does userspace know that ITS guests always require devid? I guess it's okay to return -EINVAL if the userspace doesn't set the flag but the virtual hardware requires it. Paolo > The question is if userspace code that sets the devid flag will anyway > depend on some discovery mechanism of whether or not the kernel supports > arm64 irqfd etc. and if so, can we be sure to add the required support > at once in the kernel so that EINVAL never means 'you set the flags > field on the ioctl on an old kernel'? > > This smells an awful lot like a capability to me. _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
