From: Konrad Rzeszutek Wilk <firstname.lastname@example.org> To: David Vrabel <email@example.com> Cc: firstname.lastname@example.org, Ian Jackson <Ian.Jackson@eu.citrix.com>, email@example.com, firstname.lastname@example.org, Paul.Durrant@citrix.com, email@example.com Subject: Re: [RFC PATCH] blkif.h: document scsi/0x12/0x83 node Date: Tue, 22 Mar 2016 10:10:06 -0400 [thread overview] Message-ID: <20160322141006.GA26390@char.us.oracle.com> (raw) In-Reply-To: <56F14B97.firstname.lastname@example.org> On Tue, Mar 22, 2016 at 01:41:43PM +0000, David Vrabel wrote: > On 22/03/16 12:55, Bob Liu wrote: > > > > On 03/17/2016 07:12 PM, Ian Jackson wrote: > >> David Vrabel writes ("Re: [Xen-devel] [RFC PATCH] blkif.h: document scsi/0x12/0x83 node"): > >>> On 16/03/16 13:59, Bob Liu wrote: > >>>> But we'd like to get the VPD information(of underlying storage device) also in Linux blkfront, even blkfront is not a SCSI device. > >>> > >>> Why does blkback/blkfront need to involved here? This is just some > >>> xenstore keys that can be written by the toolstack and directly read by > >>> the relevant application in the guest. > >> > > > > They want a more generic way because the application may run on all kinds of environment including baremetal. > > So they prefers to just call ioctl(SG_IO) against a storage device. > > > >> I'm getting rather a different picture here than at first. Previously > >> I thought you had some 3rd-party application, not under your control, > >> which expected to see this VPD data. > >> > >> But now I think that you're saying the application is under your own > >> control. I don't understand why synthetic VPD data is the best way to > >> give your application the information it needs. > >> > >> What is the application doing with this VPD data ? I mean, > >> which specific application functions, and how do they depend on the > >> VPD data ? > >> > > > > From the feedbacks I just got, they do *not* want the details to be in public. > > It is difficult to suggest how it should be done correctly without this > information. Just think of it as a black box. > > I also find it difficult to see a use case where running the storage > software in the guest (instead of in the backend) is sensible or desirable. Are you suggesting that doing backend drivers is not sensible? > > > Anyway, I think this is not a block of this patch. > > In Windows PV block driver, we already use the same way to get the raw INQUIRY data. > > * The Windows PV block driver accepts ioctl(SG_IO). > > * Then it reads this /scsi/0x12/0x83 node. > > * Then return the raw INQURIY data back to ioctl. > > > > Since Linux guest also wants to do the same thing, let's making this mechanism to be a generic interface! > > I'll post a patch adding ioctl(SG_IO) support to xen-blkfront together with a updated version of this patch soon. > > I do not think this feature is generally useful outside of this > unspecified use case. I do not think that supplying details about > underlying storage device (beyond generic properties) to guests is > sensible (e.g., what if the guest snapshot is restored on different > storage?). The restore process (xl) can update the XenStore key with the new storage. > > And thus I do not not think we should either: a) make this part of the > blkif ABI; or b) add support to xen-blkfront or xen-blkback. It is already coded in Windows PV drivers so I am not following why codyfing this in the blkif.h is harmful? > > David > > _______________________________________________ > Xen-devel mailing list > Xenemail@example.com > http://lists.xen.org/xen-devel _______________________________________________ Xen-devel mailing list Xenfirstname.lastname@example.org http://lists.xen.org/xen-devel
next prev parent reply other threads:[~2016-03-22 14:10 UTC|newest] Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top 2016-03-16 3:09 Bob Liu 2016-03-16 7:16 ` Konrad Rzeszutek Wilk 2016-03-16 12:36 ` Ian Jackson 2016-03-16 13:59 ` Bob Liu 2016-03-16 14:07 ` Paul Durrant 2016-03-17 5:04 ` Bob Liu 2016-03-16 14:32 ` David Vrabel 2016-03-17 5:07 ` Bob Liu 2016-03-17 11:12 ` Ian Jackson 2016-03-17 11:18 ` David Vrabel 2016-03-17 11:20 ` Ian Jackson 2016-03-22 12:55 ` Bob Liu 2016-03-22 13:41 ` David Vrabel 2016-03-22 14:10 ` Konrad Rzeszutek Wilk [this message] 2016-03-22 14:38 ` David Vrabel 2016-03-22 14:43 ` Paul Durrant 2016-03-22 15:09 ` Ian Jackson 2016-03-22 15:25 ` Paul Durrant 2016-03-22 16:14 ` Ian Jackson 2016-03-22 16:50 ` Konrad Rzeszutek Wilk 2016-03-22 17:39 ` Paul Durrant 2016-03-22 15:12 ` Ian Jackson 2016-03-22 15:27 ` Konrad Rzeszutek Wilk 2016-03-22 16:11 ` Ian Jackson 2016-03-22 16:38 ` Konrad Rzeszutek Wilk 2016-03-22 16:25 ` Jan Beulich 2016-03-16 14:33 ` Ian Jackson
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20160322141006.GA26390@char.us.oracle.com \ --email@example.com \ --cc=Ian.Jackson@eu.citrix.com \ --cc=Paul.Durrant@citrix.com \ --firstname.lastname@example.org \ --email@example.com \ --firstname.lastname@example.org \ --email@example.com \ --firstname.lastname@example.org \ --subject='Re: [RFC PATCH] blkif.h: document scsi/0x12/0x83 node' \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: link
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for NNTP newsgroup(s).