On 05/23/2011 04:02 PM, Joerg Roedel wrote:
On Mon, May 23, 2011 at 12:52:50PM +0300, Avi Kivity wrote:
> On 05/22/2011 10:32 PM, Nadav Har'El wrote:
>> What do we need to do with this idt-vectoring-information? In regular (non-
>> nested) guests, the answer is simple: On the next entry, we need to inject
>> this event again into the guest, so it can resume the delivery of the
>> same event it was trying to deliver. This is why the nested-unaware code
>> has a vmx_complete_interrupts which basically adds this idt-vectoring-info
>> into KVM's event queue, which on the next entry will be injected similarly
>> to the way virtual interrupts from userspace are injected, and so on.
>
> The other thing we may need to do, is to expose it to userspace in case
> we're live migrating at exactly this point in time.
About live-migration with nesting, we had discussed the idea of just
doing an VMEXIT(INTR) if the vcpu runs nested and we want to migrate.
The problem was that the hypervisor may not expect an INTR intercept.
How about doing an implicit VMEXIT in this case and an implicit VMRUN
after the vcpu is migrated?
What if there's something in EXIT_INT_INFO?
The nested hypervisor will not see the
vmexit and the vcpu will be in a state where it is safe to migrate. This
should work for nested-vmx too if the guest-state is written back to
guest memory on VMEXIT. Is this the case?
It is the case with the current implementation, and we can/should make
it so in future implementations, just before exit to userspace. Or at
least provide an ABI to sync memory.
But I don't see why we shouldn't just migrate all the hidden state (in
guest mode flag, svm host paging mode, svm host interrupt state, vmcb
address/vmptr, etc.). It's more state, but no thinking is involved, so
it's clearly superior.
--
error compiling committee.c: too many arguments to function
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