On Mon, Apr 11, 2022, Zeng Guang wrote: > From: Maxim Levitsky <mlevitsk@xxxxxxxxxx> > > No normal guest has any reason to change physical APIC IDs, and > allowing this introduces bugs into APIC acceleration code. > > And Intel recent hardware just ignores writes to APIC_ID in > xAPIC mode. More background can be found at: > https://lore.kernel.org/lkml/Yfw5ddGNOnDqxMLs@xxxxxxxxxx/ > > Looks there is no much value to support writable xAPIC ID in > guest except supporting some old and crazy use cases which > probably would fail on real hardware. So, make xAPIC ID > read-only for KVM guests. AFAIK, the plan is to add a capability to let userspace opt-in to a fully read-only APIC ID[*], but I haven't seen patches... Maxim? [*] https://lore.kernel.org/all/c903e82ed2a1e98f66910c35b5aabdcf56e08e72.camel@xxxxxxxxxx
