From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 17 Mar 2020 12:11:47 +0000 From: "Dr. David Alan Gilbert" Message-ID: <20200317121147.GA3369@work-vm> References: <20200317104151.414e2a0b@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200317104151.414e2a0b@redhat.com> Subject: Re: [Virtio-fs] virtio-fs on zLinux (s390x) List-Id: Development discussions about virtio-fs List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Igor Mammedov Cc: virtio-fs@redhat.com, Cornelia Huck * Igor Mammedov (imammedo@redhat.com) wrote: > On Tue, 17 Mar 2020 02:05:06 -0500 > "Gong Su" wrote: > > > > > > > Hi Igor, just wondering if there is any updates on getting the patches that > > will allow shared memory without -numa (not supported on s390 yet)? Thanks. > > it's already upstream. > > there is a new upstream option -machine memory-backend=... > that allows to set custom backend for main RAM SOmething like: -object memory-backend-memfd,size=2G,id=mem,share=on -machine pc,memory-backend=mem seems to be the syntax then. Good, that does make life simpler. Dave > > __________________ > > > > Hi Igor, that would be great. Thanks. > > > > > > > > From: Igor Mammedov > > To: "Gong Su" > > Cc: "Dr. David Alan Gilbert" , Cornelia Huck > > , virtio-fs@redhat.com > > Date: 12/13/2019 08:17 AM > > Subject: [EXTERNAL] Re: [Virtio-fs] virtio-fs on zLinux (s390x) > > > > > > > > On Thu, 12 Dec 2019 14:10:32 -0500 > > "Gong Su" 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" > > > To: Gong Su > > > Cc: virtio-fs@redhat.com, Cornelia Huck > > > Date: 12/12/2019 01:59 PM > > > Subject: [EXTERNAL] Re: [Virtio-fs] virtio-fs on zLinux (s390x) > > > > > > > > > > > > * Gong Su (gongsu@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@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@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@redhat.com / Manchester, UK > > > > > > > > > > > > > > > > > > > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK