Messages in this thread | | | Subject | Re: [PATCH v2 5/5] KVM: x86: hyper-v: Deactivate APICv only when AutoEOI feature is in use | From | Paolo Bonzini <> | Date | Tue, 25 May 2021 09:11:10 +0200 |
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On 25/05/21 08:23, Vitaly Kuznetsov wrote: >> Should it also disable APICv unconditionally if >> HV_DEPRECATING_AEOI_RECOMMENDED is not in the guest CPUID? That should >> avoid ping-pong between enabled and disabled APICv even in pathological >> cases that we cannot think about. > When you run Hyper-V on KVM it doesn't use SynIC (let alone AutoEOI) but > we still inhibit APICv unconditionally. The patch as-is improves this > without any userspace changes required and I see it as a benefit. Going > forward, we will definitely add something like 'hv-synic-noaeoi' to QEMU > to make non-nesting setups benefit too but it'll take a while for this > option to propagate to real world configurations (sigh).
Ok, if enable<->disable APICv becomes an issue we can also consider disabling APICv forever if AutoEOI is ever used.
Paolo
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