Am 23.10.2023 um 11:30 hat Igor Mammedov geschrieben: > On Wed, 18 Oct 2023 09:32:47 +0100 > David Woodhouse <dwmw2@xxxxxxxxxxxxx> 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@xxxxxxxxxxxxx> wrote: > > > > > > > From: David Woodhouse <dwmw@xxxxxxxxxxxx> > > > > > > > > > > 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
