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.
The problem with debugfs is that it's not accessible to the user that
created the VM, but only root, right?
That said, I don't feel very strongly here.
Alex
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