On Tue, Feb 04, 2025, Naveen N Rao wrote: > On Mon, Feb 03, 2025 at 09:00:05PM -0500, Maxim Levitsky wrote: > > On Mon, 2025-02-03 at 22:33 +0530, Naveen N Rao (AMD) wrote: > > > apicv_update_lock is not required when querying the state of guest > > > debug in all the vcpus. Remove usage of the same, and switch to > > > kvm_set_or_clear_apicv_inhibit() helper to simplify the code. > > > > It might be worth to mention that the reason why the lock is not needed, > > is because kvm_vcpu_ioctl from which this function is called takes 'vcpu->mutex' > > and thus concurrent execution of this function is not really possible. > > Looking at this again, that looks to be a vcpu-specific lock, so I guess > it is possible for multiple vcpus to run this concurrently? Correct. > In reality, this looks to be coming in from a vcpu ioctl from userspace, > so this is probably not being invoked concurrently today. > > Regardless, I wonder if moving this to a per-vcpu inhibit might be a > better way to address this. No, this is a slow path.
