On 2016/1/7 22:56, Peter Maydell wrote: >>>> + Errors: >>>> >>> + -ENXIO: Unsupported attribute group >>>> >>> + -EBUSY: The PMU overflow interrupt is already set >>>> >>> + -ENODEV: Getting the PMU overflow interrupt number while it's not set >>>> >>> + -EINVAL: Invalid vcpu_index or PMU overflow interrupt number supplied >>> >> >>> >> What happens if you create a PMU but then never set the IRQ number? >>> >> Is there a default or does the VM refuse to run or something? >>> >> >> > If userspace doesn't specify the irq number, the guest will not receive >> > the PMU interrupt because we check if the irq is initialized when we >> > inject the interrupt. But guest could still use the vPMU if QEMU >> > generates a proper DTB or ACPI. > So is it a valid use case to create a PMU with the interrupt not wired > up to anything? (If it's never valid it would be nice to diagnose it > rather than just silently letting the guest run but not work right.) So how about adding a helper to check if the PMU is completely initialized and if not, return trap_raz_wi when guest access PMU registers? Thanks, -- 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
