Re: [PATCH v5 4/7] kvm, mem-hotplug: Reload L1' apic access page on migration in vcpu_enter_guest().

[Paolo Bonzini]

Il 11/09/2014 13:30, Gleb Natapov ha scritto:
>> > +			vmcs_write64(APIC_ACCESS_ADDR, page_to_phys(page));
>> > +			/*
>> > +			 * Do not pin apic access page in memory so that memory
>> > +			 * hotplug process is able to migrate it.
>> > +			 */
>> > +			put_page(page);
>> >  		}
> This code is in prepare_vmcs02() and is executed during L1->L2 vmentry. What happens
> when apic access page is migrated while L2 is running? It needs to be update somewhere.

Before it is migrated, the MMU notifier is called and will force a
vmexit on all CPUs.  The reload code will call GUP again on the page
again and swap it in.

Paolo

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/