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

tangchen
2014-09-12T03:35:24Z

Hi Paolo,

On 09/11/2014 10:24 PM, Paolo Bonzini wrote:
> Il 11/09/2014 16:21, Gleb Natapov ha scritto:
>> As far as I can tell the if that is needed there is:
>>
>> if (!is_guest_mode() || !(vmcs12->secondary_vm_exec_control & ECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES))
>> write(PIC_ACCESS_ADDR)
>>
>> In other words if L2 shares L1 apic access page then reload, otherwise do nothing.
> What if the page being swapped out is L1's APIC access page? We don't
> run prepare_vmcs12 in that case because it's an L2->L0->L2 entry, so we
> need to "do something".

Are you talking about the case that L1 and L2 have different apic pages ?
I think I didn't deal with this situation in this patch set.

Sorry I didn't say it clearly. Here, I assume L1 and L2 share the same
apic page.
If we are in L2, and the page is migrated, we updated L2's vmcs by
making vcpu
request. And of course, we should also update L1's vmcs. This is done by
patch 5.
We make vcpu request again in nested_vmx_exit().

Thanks.