On Jun 3, 2022, at 11:34 AM, Yu Zhang <[email protected]<mailto:[email protected]>> wrote:
Hello Dongli, Elena, John, and Jagannathan, I'm interested in the "multi-process QEMU" feature and got the kind reply by Mr. Vivier that I may contact you for this. On one of the QEMU docs [1] I saw the command line: + /usr/bin/qemu-system-x86_64 \ + -machine x-remote \ + -device lsi53c895a,id=lsi0 \ + -drive id=drive_image2,file=/build/ol7-nvme-test-1.qcow2 \ + -device scsi-hd,id=drive2,drive=drive_image2,bus=lsi0.0,scsi-id=0 \ + -object x-remote-object,id=robj1,devid=lsi1,fd=4, It seems that the man page of qemu contains no parameter and option yet for this feature. The qemu docs, such as [2][3][4] are either not up-to-date or "doesn't reflect the current status of the implementation". So may I know whether is it still in experimental stage or mature enough for use? And even a few further questions: Hello Yu, We are working on vfio-user for QEMU which would supersede multi-process QEMU. The vfio-user feature is currently under review for merging with QEMU. We would drop multi-process QEMU support after the vfio-user changes are merged. We use the following repo for testing vfio-user before sending the patches for review. You may be interested in checking it out: https://github.com/oracle/qemu/tree/master - When creating the orchestrator, can we specify a machine type such as pc-i440fx-7.0 for -machine? For vfio-user, the machine type on the remote QEMU process (server) is always “x-remote”. The client QEMU could be of any machine type. - Can each device has a dedicated emulation process or shares one process for emulating multiple devices? Each device could be running in a dedicated process, or multiple devices could share one process. - Can we find more command line examples showing the combination of orchestrator, remote emulation process, memory-backend-memfd and x-pci-proxy-dev? For vfio-user, we could give you a heads up once they are merged into QEMU. We are using the following for testing our changes, which you could checkout in the meanwhile: scripts/vfiouser-launcher.py Could you please give us more details about what you’re trying to do? Which devices are you trying to emulate in the remote process? Thank you! -- Jag Thank you very much and all the best Yu Zhang 03.06.2022 [1] https://www.qemu.org/docs/master/system/multi-process.html [2] https://wiki.qemu.org/Features/MultiProcessQEMU [3] https://lxr.missinglinkelectronics.com/qemu+v7.0.0/docs/devel/multi-process.rst [4] https://qemu.readthedocs.io/en/latest/devel/multi-process.html ---------- Forwarded message --------- From: Laurent Vivier <[email protected]<mailto:[email protected]>> Date: Fri, Jun 3, 2022 at 4:14 PM Subject: Re: about the current status of Multi-process QEMU / out-of-process emulation To: Yu Zhang <[email protected]<mailto:[email protected]>> Hi Yu, I'm not the author of this documentation, only the person that has merged the last change in the repo. According to the logs you should contact Dongli Zhang <[email protected]<mailto:[email protected]>>, Elena Ufimtseva <[email protected]<mailto:[email protected]>>, John G Johnson <[email protected]<mailto:[email protected]>> or Jagannathan Raman <[email protected]<mailto:[email protected]>> . Thanks, Laurent Le 03/06/2022 à 12:17, Yu Zhang a écrit : > Dear Mr. Vivier, > > I saw that you authored the QEMU page for "Multi-process QEMU". > (https://www.qemu.org/docs/master/system/multi-process.html > <https://www.qemu.org/docs/master/system/multi-process.html>) > > I'm interested in this feature, but feel a little confused with the command > line: > > + /usr/bin/qemu-system-x86_64 \ > + -machine x-remote \ > + -device lsi53c895a,id=lsi0 \ > + -drive id=drive_image2,file=/build/ol7-nvme-test-1.qcow2 \ > + -device scsi-hd,id=drive2,drive=drive_image2,bus=lsi0.0,scsi-id=0 \ > + -object x-remote-object,id=robj1,devid=lsi1,fd=4, > > It seems that the man page of qemu command contains no parameter and option > yet for this feature. > May I know whether is it still in experimental stage? And even a few more > questions: > > - Is "x-remote" a standalone machine type for creating the orchestrator? > - Can each device has a dedicated emulation process or shares one process for > emulating multiple > devices? > - Can I find more command line examples illustrating the combination of > orchestrator, remote > emulation process, memory-backend-memfd and x-pci-proxy-dev? > > Thank you very much > Kind regard > > Yu Zhang > 03.06.2022
