> Am 28.08.2019 um 20:41 schrieb Suthikulpanit, Suravee <Suravee.Suthikulpanit@xxxxxxx>: > > Alex, > >> On 8/27/19 3:20 AM, Alexander Graf wrote: >> >> >>> On 26.08.19 21:41, Suthikulpanit, Suravee wrote: >>> Alex, >>> >>>> On 8/19/2019 4:57 AM, Alexander Graf wrote: >>>> >>>> >>>>> On 15.08.19 18:25, Suthikulpanit, Suravee wrote: >>>>> Currently, there is no way to tell whether APICv is active >>>>> on a particular VM. This often cause confusion since APICv >>>>> can be deactivated at runtime. >>>>> >>>>> Introduce a debugfs entry to report APICv state of a VM. >>>>> This creates a read-only file: >>>>> >>>>> /sys/kernel/debug/kvm/70860-14/apicv-state >>>>> >>>>> Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx> >>>> >>>> Shouldn't this first and foremost be a VM ioctl so that user space >>>> can inquire its own state? >>>> >>>> >>>> Alex >>> >>> I introduce this mainly for debugging similar to how KVM is currently >>> provides >>> some per-VCPU information: >>> >>> /sys/kernel/debug/kvm/15957-14/vcpu0/ >>> lapic_timer_advance_ns >>> tsc-offset >>> tsc-scaling-ratio >>> tsc-scaling-ratio-frac-bits >>> >>> I'm not sure if this needs to be VM ioctl at this point. If this >>> information is >>> useful for user-space tool to inquire via ioctl, we can also provide it. >> >> I'm mostly thinking of something like "info apic" in QEMU which to me >> seems like the natural place for APIC information exposure to a user. > > I could not find QEMU "info apic". I assume you meant "info lapic", > which provides information specific to each local APIC (i.e. per-vcpu). Or maybe even "info kvm" :). I think you get the point. > >> The problem with debugfs is that it's not accessible to the user that >> created the VM, but only root, right? > > Hm, you are right. I'll also look into also adding ioctl interface then. Thanks! Alex Amazon Development Center Germany GmbH Krausenstr. 38 10117 Berlin Geschaeftsfuehrung: Christian Schlaeger, Ralf Herbrich Eingetragen am Amtsgericht Charlottenburg unter HRB 149173 B Sitz: Berlin Ust-ID: DE 289 237 879
