[ovirt-devel] Re: device compatibility interface for live migration with assigned devices

On Thu, 16 Jul 2020 16:32:30 +0800 Yan Zhao <yan.y.zhao(a)intel.com&gt; wrote: > On Thu, Jul 16, 2020 at 12:16:26PM +0800, Jason Wang wrote: >> On 2020/7/14 上午7:29, Yan Zhao wrote: >>> hi folks, >>> we are defining a device migration compatibility interface that helps upper >>> layer stack like openstack/ovirt/libvirt to check if two devices are >>> live migration compatible. >>> The "devices" here could be MDEVs, physical devices, or hybrid of the two. >>> e.g. we could use it to check whether >>> - a src MDEV can migrate to a target MDEV, >>> - a src VF in SRIOV can migrate to a target VF in SRIOV, >>> - a src MDEV can migration to a target VF in SRIOV. >>> (e.g. SIOV/SRIOV backward compatibility case) >>> >>> The upper layer stack could use this interface as the last step to check >>> if one device is able to migrate to another device before triggering a real >>> live migration procedure. >>> we are not sure if this interface is of value or help to you. please don't >>> hesitate to drop your valuable comments. >>> >>> >>> (1) interface definition >>> The interface is defined in below way: >>> >>> __ userspace >>> /\ \ >>> / \write >>> / read \ >>> ________/__________ ___\|/_____________ >>> | migration_version | | migration_version |-->check migration >>> --------------------- --------------------- compatibility >>> device A device B >>> >>> >>> a device attribute named migration_version is defined under each device's >>> sysfs node. e.g. (/sys/bus/pci/devices/0000\:00\:02.0/$mdev_UUID/migration_version). >> >> Are you aware of the devlink based device management interface that is >> proposed upstream? I think it has many advantages over sysfs, do you >> consider to switch to that? Advantages, such as?