On Mon, Feb 04, 2019 at 04:46:00PM +0100, Cédric Le Goater wrote: > On 2/4/19 6:18 AM, David Gibson wrote: > > On Mon, Jan 07, 2019 at 07:43:26PM +0100, Cédric Le Goater wrote: > >> When the VM is stopped in a migration sequence, the sources are masked > >> and the XIVE IC is synced to stabilize the EQs. When done, the KVM > >> ioctl KVM_DEV_XIVE_SAVE_EQ_PAGES is called to mark dirty the EQ pages. > >> > >> The migration can then transfer the remaining dirty pages to the > >> destination and start collecting the state of the devices. > > > > Is there a reason to make this a separate step from the SYNC > > operation? > > Hmm, apart from letting QEMU orchestrate the migration step by step, no. > > We could merge the SYNC and the SAVE_EQ_PAGES in a single KVM operation. > I think that should be fine. I think that makes sense. SYNC is supposed to complete delivery of any in-flight interrupts, and to me writing to the queue page and marking it dirty as a result is a logical part of that. > However, it does not make sense to call this operation without the VM > being stopped. I wonder how this can checked from KVM. May be we > can't. I don't think it matters. qemu is allowed to shoot itself in the foot. -- 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
Attachment:
signature.asc
Description: PGP signature
