[Virtio-fs] virtio-fs on zLinux (s390x)

[Igor Mammedov]

On Thu, 12 Dec 2019 14:10:32 -0500
"Gong Su" <gongsu at us.ibm.com> wrote:

> 
> Thanks Dave. That was quick!
> 
> Igor, any idea when this will happen? :-)
If you need early sneak peek, I can post common + s390 patches.

 
> From:	"Dr. David Alan Gilbert" <dgilbert at redhat.com>
> To:	Gong Su <gongsu at us.ibm.com>
> Cc:	virtio-fs at redhat.com, Cornelia Huck <cohuck at redhat.com>
> Date:	12/12/2019 01:59 PM
> Subject:	[EXTERNAL] Re: [Virtio-fs] virtio-fs on zLinux (s390x)
> 
> 
> 
> * Gong Su (gongsu at us.ibm.com) wrote:
> >
> >
> > Hi Stefan, I'm resending my questions to the list per your request.
> >
> > Basically, I'm trying to see if I can get virtio-fs to work on zLinux.
> > Following the instructions on
> https://urldefense.proofpoint.com/v2/url?u=https-3A__virtio-2Dfs.gitlab.io_howto-2Dqemu.html&d=DwIFAg&c=jf_iaSHvJObTbx-siA1ZOg&r=tf-1fDxgEPUcSzS0GcREznaRLLY6eGivTqJEnr2bEmQ&m=bKfrjedGnP-cXu2BPH6ynhTbdi5nm0VW1nx6Qb5Q_7M&s=pkvbWd3P-tWRpKPww5iwoPHLE_HnkenEEJhywABpRuc&e=
>   I
> > was able to compile all the pieces but when I tried to run qemu I
> realized
> > that it needs -numa option which isn't supported on s390x yet.
> >
> > I have talked to Christian Borntraeger (whom I worked with on other
> > projects before) and he indicated that he had a plan to add -numa support
> > for s390x but currently is busy on other things.
> >
> > So I'm trying to see if there are other ways for me to go forward without
> > having to wait for Christian. I see two options:
> >
> > 1. Merge virtiofsd into qemu itself. In the "Interchangeability" section
> of
> > the virtio-fs design page (
> https://urldefense.proofpoint.com/v2/url?u=https-3A__virtio-2Dfs.gitlab.io_design.html&d=DwIFAg&c=jf_iaSHvJObTbx-siA1ZOg&r=tf-1fDxgEPUcSzS0GcREznaRLLY6eGivTqJEnr2bEmQ&m=bKfrjedGnP-cXu2BPH6ynhTbdi5nm0VW1nx6Qb5Q_7M&s=2VrG3dsgZcdW8uO6ZBiGtRgNp4X1z3d8TMXnUdHhfCc&e=
>  ), it
> > mentioned that "It is also possible to forego vhost-user and emulate the
> > virtio-fs device directly inside the hypervisor, although this may result
> > in poor isolation and security." Since each guest typically gets its own
> > qemu process, maybe this is acceptable for some use cases. In exchange,
> you
> > get the benefit of not having to carve out a chunk of memory
> from /dev/shm
> > (and maybe simpler communication between virtiofsd and qemu).
> > 2. Use something other than -numa to share memory between virtiofsd and
> > qemu that's supported on zLinux. I'm not entirely familiar with qemu so I
> > have no idea whether this is possible or not.
> 
> Hi,
>   My understanding is that Igor Mammedov (imammedo at redhat.com) has plans
> to allow 'shared' to be set on main memory, so we wouldn't need the numa
> code.
> 
> Dave
> 
> > Thanks.
> 
> > _______________________________________________
> > Virtio-fs mailing list
> > Virtio-fs at redhat.com
> >
> https://urldefense.proofpoint.com/v2/url?u=https-3A__www.redhat.com_mailman_listinfo_virtio-2Dfs&d=DwIFAg&c=jf_iaSHvJObTbx-siA1ZOg&r=tf-1fDxgEPUcSzS0GcREznaRLLY6eGivTqJEnr2bEmQ&m=bKfrjedGnP-cXu2BPH6ynhTbdi5nm0VW1nx6Qb5Q_7M&s=O41fLQGJCOR0-Aj2Y4nziy3aTYTOCzaH8Lahe7xhBK8&e=
> 
> 
> --
> Dr. David Alan Gilbert / dgilbert at redhat.com / Manchester, UK
> 
> 
> 
>