Re: [libvirt RFCv11 00/33] multifd save restore prototype

On 10/11/23 17:29, Daniel P. Berrangé wrote: > On Wed, Oct 11, 2023 at 04:56:12PM +0200, Claudio Fontana wrote: >> >> On 10/11/23 16:05, Daniel P. Berrangé wrote: >>> >>> Instead of using 'getfd' though we have to use 'add-fd'. >>> >>> Anyway, this lets us do FD passing as normal, whle also >>> letting us specify the offset. >>> >>> {"execute": "add-fd", "arguments": {"fdset-id":"migrate"}} >>> {"execute": "migrate", "arguments": {"detach":true,"blk":false,"inc":false,"uri":"file:/dev/fdset/migrate,offset=124456"}}' Hi Daniel, the "add-fd" is the part that I don't understand at all, should we actually pass an fd there like with fd-get, already open with the savevm file? Something in pseudocode like: virsh qemu-monitor-command --pass-fds 10 --cmd='{"execute": "add-fd", "arguments": {"fdset-id":10}} ? should we use "opaque" instead of "fdset-id" if you want to actually set it to "migrate"? And how to reference it later? virsh qemu-monitor-command --cmd='{"execute": "migrate", "arguments": {"detach":true,"blk":false,"inc":false,"uri":"file:/dev/fdset/migrate,offset=124456"}} ? "opaque" does not seem to get me a reachable /dev/fdset/migrate though. I can currently trigger the migration to the URI file:/mnt/nvme/savevm so that seems to work fine, it's the file:/dev/fdset part that I am still unable to glue together.