From: Kevin Wolf <kwolf@redhat.com>
To: Igor Mammedov <imammedo@redhat.com>
Cc: "David Woodhouse" <dwmw2@infradead.org>,
qemu-devel@nongnu.org, "Hanna Reitz" <hreitz@redhat.com>,
"Stefano Stabellini" <sstabellini@kernel.org>,
"Anthony Perard" <anthony.perard@citrix.com>,
"Paul Durrant" <paul@xen.org>,
"Marc-André Lureau" <marcandre.lureau@redhat.com>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Michael S. Tsirkin" <mst@redhat.com>,
"Marcel Apfelbaum" <marcel.apfelbaum@gmail.com>,
"Richard Henderson" <richard.henderson@linaro.org>,
"Eduardo Habkost" <eduardo@habkost.net>,
"Marcelo Tosatti" <mtosatti@redhat.com>,
qemu-block@nongnu.org, xen-devel@lists.xenproject.org,
kvm@vger.kernel.org, "Daniel P. Berrangé" <berrange@redhat.com>
Subject: Re: [PATCH 11/12] hw/xen: automatically assign device index to block devices
Date: Mon, 23 Oct 2023 15:45:51 +0200 [thread overview]
Message-ID: <ZTZ5D2wZXkDQanbQ@redhat.com> (raw)
In-Reply-To: <20231023113002.0e83c209@imammedo.users.ipa.redhat.com>
Am 23.10.2023 um 11:30 hat Igor Mammedov geschrieben:
> On Wed, 18 Oct 2023 09:32:47 +0100
> David Woodhouse <dwmw2@infradead.org> wrote:
>
> > On Wed, 2023-10-18 at 09:32 +0200, Igor Mammedov wrote:
> > > On Mon, 16 Oct 2023 16:19:08 +0100
> > > David Woodhouse <dwmw2@infradead.org> wrote:
> > >
> > > > From: David Woodhouse <dwmw@amazon.co.uk>
> > > >
> > >
> > > is this index a user (guest) visible?
> >
> > Yes. It defines what block device (e.g. /dev/xvda) the disk appears as
> > in the guest. In the common case, it literally encodes the Linux
> > major/minor numbers. So xvda (major 202) is 0xca00, xvdb is 0xca10 etc.
>
> that makes 'index' an implicit ABI and a subject to versioning
> when the way it's assigned changes (i.e. one has to use versioned
> machine types to keep older versions working the they used to).
>
> From what I remember it's discouraged to make QEMU invent
> various IDs that are part of ABI (guest or mgmt side).
> Instead it's preferred for mgmt side/user to provide that explicitly.
>
> Basically you are trading off manageability/simplicity at QEMU
> level with CLI usability for human user.
> I don't care much as long as it is hidden within xen code base,
> but maybe libvirt does.
-drive is mostly a convenience option for human users anyway. Management
tools should use a combination of -blockdev and -device.
Kevin
next prev parent reply other threads:[~2023-10-23 13:46 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-16 15:18 [PATCH 0/12] Get Xen PV shim running in qemu David Woodhouse
2023-10-16 15:18 ` [PATCH 01/12] i386/xen: fix per-vCPU upcall vector for Xen emulation David Woodhouse
2023-10-24 12:16 ` Paul Durrant
2023-10-24 12:58 ` David Woodhouse
2023-10-16 15:18 ` [PATCH 02/12] hw/xen: select kernel mode for per-vCPU event channel upcall vector David Woodhouse
2023-10-24 12:29 ` Paul Durrant
2023-10-24 13:20 ` David Woodhouse
2023-10-16 15:19 ` [PATCH 03/12] include: update Xen public headers to Xen 4.17.2 release David Woodhouse
2023-10-24 12:30 ` Paul Durrant
2023-10-16 15:19 ` [PATCH 04/12] i386/xen: advertise XEN_HVM_CPUID_UPCALL_VECTOR in CPUID David Woodhouse
2023-10-24 12:32 ` Paul Durrant
2023-10-16 15:19 ` [PATCH 05/12] hw/xen: populate store frontend nodes with XenStore PFN/port David Woodhouse
2023-10-24 12:35 ` Paul Durrant
2023-10-24 12:53 ` David Woodhouse
2023-10-16 15:19 ` [PATCH 06/12] hw/xen: add get_frontend_path() method to XenDeviceClass David Woodhouse
2023-10-24 12:42 ` Paul Durrant
2023-10-24 12:56 ` David Woodhouse
2023-10-24 12:59 ` Paul Durrant
2023-10-24 13:29 ` David Woodhouse
2023-10-24 13:37 ` Paul Durrant
2023-10-25 8:30 ` David Woodhouse
2023-11-21 12:25 ` David Woodhouse
2023-10-16 15:19 ` [PATCH 07/12] hw/xen: update Xen console to XenDevice model David Woodhouse
2023-10-24 13:07 ` Paul Durrant
2023-10-16 15:19 ` [PATCH 08/12] hw/xen: do not repeatedly try to create a failing backend device David Woodhouse
2023-10-24 13:19 ` Paul Durrant
2023-10-16 15:19 ` [PATCH 09/12] hw/xen: prevent duplicate device registrations David Woodhouse
2023-10-24 14:10 ` Paul Durrant
2023-10-24 14:38 ` David Woodhouse
2023-10-16 15:19 ` [PATCH 10/12] hw/xen: automatically assign device index to console devices David Woodhouse
2023-10-16 15:19 ` [PATCH 11/12] hw/xen: automatically assign device index to block devices David Woodhouse
2023-10-17 10:21 ` Kevin Wolf
2023-10-17 18:02 ` David Woodhouse
2023-10-18 7:32 ` Igor Mammedov
2023-10-18 8:32 ` David Woodhouse
2023-10-23 9:30 ` Igor Mammedov
2023-10-23 9:42 ` David Woodhouse
2023-10-23 9:42 ` David Woodhouse
2023-10-23 13:45 ` Kevin Wolf [this message]
2023-10-18 8:52 ` Kevin Wolf
2023-10-18 10:52 ` David Woodhouse
2023-10-19 11:21 ` Kevin Wolf
2023-10-20 17:47 ` David Woodhouse
2023-10-18 23:13 ` David Woodhouse
2023-10-16 15:19 ` [PATCH 12/12] hw/xen: add support for Xen primary console in emulated mode David Woodhouse
2023-10-24 14:20 ` Paul Durrant
2023-10-24 15:37 ` David Woodhouse
2023-10-24 15:39 ` Paul Durrant
2023-10-24 15:49 ` David Woodhouse
2023-10-24 16:25 ` Paul Durrant
2023-10-24 16:34 ` David Woodhouse
2023-10-25 8:31 ` Paul Durrant
2023-10-25 9:00 ` David Woodhouse
2023-10-25 10:44 ` Paul Durrant
2023-10-24 15:24 ` [PATCH 0/12] Get Xen PV shim running in qemu Alex Bennée
2023-10-24 16:11 ` David Woodhouse
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