On Tue, Mar 12, 2019 at 06:00:38PM +0100, Cédric Le Goater wrote:

On 2/25/19 3:39 AM, David Gibson wrote:

quoted

On Fri, Feb 22, 2019 at 12:28:30PM +0100, Cédric Le Goater wrote:

quoted

These controls will be used by the H_INT_SET_QUEUE_CONFIG and
H_INT_GET_QUEUE_CONFIG hcalls from QEMU. They will also be used to
restore the configuration of the XIVE EQs in the KVM device and to
capture the internal runtime state of the EQs. Both 'get' and 'set'
rely on an OPAL call to access from the XIVE interrupt controller the
EQ toggle bit and EQ index which are updated by the HW when event
notifications are enqueued in the EQ.

The value of the guest physical address of the event queue is saved in
the XIVE internal xive_q structure for later use. That is when
migration needs to mark the EQ pages dirty to capture a consistent
memory state of the VM.

To be noted that H_INT_SET_QUEUE_CONFIG does not require the extra
OPAL call setting the EQ toggle bit and EQ index to configure the EQ,
but restoring the EQ state will.

I think we need to add some kind of flags to differentiate the hcall
H_INT_SET_QUEUE_CONFIG from the restore of the EQ. The hcall does
not need OPAL support call and this could help in the code
transition.

Hrm.  What's the actual difference in the semantics between the two
cases.  The guest shouldn't have awareness of whether or not OPAL is
involved.

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson