2021-10-14 Project Stratos Sync Meeting notes
Participants
@Mike Holmes
@Joakim Bech
@Alex Bennée
@Randy Linnell
@Mathieu Poirier
@Bill Fletcher
@Vincent Guittot
@Arnd Bergmann
@Peter Griffin
@Jean-Philippe Brucker
Arnaud Pouliquan
Agenda
FYI Stefanos talk ELC21: VM-to-VM Communication Mechanisms for Embedded
Alex RPi booting Xen
Alex: Argo
Arnd fatvirtqueue
Action follow up
Discussion topics
Alex RPi booting Xen - RPi4 is booting GDOM0 with Xen, opensrc boot chain. Uboot crashing hard for a small mistake. This will be a suitable reference for Xen. Needs SSD vs SD Card which is unstable for rootfs. Propose we adopt this.
Mathieu: order now due to supply issues: Alex I have 8 gig, but it is now out of stock.
Alex ordered ArgonOne case, has not arrived yet.
Arnd have USB adapter
Mathieu : Xen appear to working with Yocto,
enabled for X86, Took 4 hours to build
Link to Alex’s artefacts https://fileserver.linaro.org/s/jC3Xq2q297j5bQ8
Alex: Should we look more at Argo, Argo does something we did not cover. Argo has hypervisor mediated copy, only one copy. HV checks. How does this work in high bandwidth situation - block device?
Alex what is the minimum number of copies: Arnd there are normally 2-3 more than you think, is this a competing solution to virtio ? Alex: written for Xens parvirt it is not the default. They are keen to open it out to be portable. Arnd, imagine that virtio not built on virt-queue, believe Xen is based on page flipping. Alex changing permission to page? Arnd yes.
Alex: does address space disappear Arnd there are multiple ways
Alex: Do we need to learn a little more about Argo? Can’t take on work, but just gathering info.
Arnd https://wiki.xenproject.org/wiki/Argo:_Hypervisor-Mediated_Exchange_(HMX)_for_Xen
Arnd Fatvirt queue: Adminvirt queues are not a replacement for fatVirtqueue. They are a way to add metadata communications to an existing queue. Adds 4th way to have out-of-band communication rather than doing it in config space. Config blobs. Posted for block devices such as TRIM etc. Spec allows this for any virtio device