Re: [libvirt PATCH v2 05/16] nodedev: add ability to list and parse defined mdevs

Jonathon Jongsma <jjongsma(a)redhat.com&gt; [2020-08-18, 09:47AM -0500]: I find this XML design for the an AP mdev rather unfortunate. First of all, it is really noisy and requires a lot of boiler-plate for the end user. Secondly, which I think it more important, it introduces a completely new and different nomenclature compared to what we currently already have for AP-related devices, i.e. cards virsh # nodedev-dumpxml ap_card05 <device> <name>ap_card05</name> <path>/sys/devices/ap/card05</path> <parent>computer</parent> <driver> <name>cex4card</name> </driver> <capability type='ap_card'> <ap-adapter>0x05</ap-adapter> </capability> </device> and queues virsh # nodedev-dumpxml ap_05_002a <device> <name>ap_05_002a</name> <path>/sys/devices/ap/card05/05.002a</path> <parent>ap_card05</parent> <driver> <name>cex4queue</name> </driver> <capability type='ap_queue'> <ap-adapter>0x05</ap-adapter> <ap-domain>0x002a</ap-domain> </capability> </device> This is really inconsistent and can be confusing for the end user. Can we instead propose something along the lines <device> <name>mdev_783e6dbb_ea0e_411f_94e2_717eaad438bf</name> <parent>matrix</parent> <capability type='mdev'> <type id='vfio_ap-passthrough'/> <iommuGroup number='0'/> <ap-adapter>0x05</ap-adapter> <ap-adapter>0x06</ap-adapter> <ap-domain>0x002a</ap-domain> <ap-domain>0x0004</ap-domain> <ap-domain>0x00ab</ap-domain> <ap-control>0x04</ap-control> </capability> </device> plus any number of enclosing elements that we like for better readability? Best, Bjoern PS: I haven't read the whole patch series, we just have an internal discussion about AP support and the XML design came up. I know that we'd like to generically treat all mdevs as the same but we also should allow for vendor-specific attributes to be represented individually to what makes sense. -- IBM Systems Linux on Z & Virtualization Development -------------------------------------------------- IBM Deutschland Research & Development GmbH Schönaicher Str. 220, 71032 Böblingen Phone: +49 7031 16 1819 -------------------------------------------------- Vorsitzende des Aufsichtsrats: Gregor Pillen Geschäftsführung: Dirk Wittkopp Sitz der Gesellschaft: Böblingen Registergericht: Amtsgericht Stuttgart, HRB 243294