On 12.12.2013 18:41, Andrey Borzenkov wrote: > В Thu, 12 Dec 2013 17:36:43 +0000 > Colin Watson пишет: > >> On Thu, Dec 12, 2013 at 05:45:30PM +0100, Vladimir 'phcoder' Serbinenko wrote: >>> No I meant full access to just obe of guest partitions. E.g. FTP may be >>> using separate partition and non-admins may have control over it. If system >>> has some kind of automatic user creation and /home is separate someone may >>> register as boot or grub and put grub.xen in his directory. If /tmp is on >>> separate partition and not in RAM then everybody can put grub.xen to >>> /tmp/grub/grub.xen >> >> Oh, right. Perhaps we could just look in a limited set of devices, e.g. >> (xen/xvda) or (xen/xvda1)? > > Is passing it as argument acceptable? That's what pvgrub1 does. AFAIU it first tries configfile passed as initrd, then configfile name passed on command line, failing both it tries netboot. Perhaps we need a parameter to make it sure that we won't try to interpret old menu.lst or to load it. E.g. grub.xenfile=(xen/xvda,1)/boot/grub/grubx64.xen or grub.config=(xen/xvda,1)/boot/grub/grub.cfg > I'm afraid that no automagic is > going to work for all cases. > What we do here is essentially define "firmware" interface that would be followed by installer. Ideally virtual nvram would be a solution but xen has none. A lazy possibility is to force creating of EFI system partition (in GPT or MBR) and load /xen/boot/boot[x64|pae].xen but probably this is far from ideal >> I'm not very familiar with how >> multi-partition Xen guests are typically set up. How is the root >> partition generally designated at the moment? >> > > As I understand it is passed as argument to kernel (i.e. in VM > definition) or embedded in initrd as usual. > There are also scenarios when guest admin has no right to modify machine description but wants to install another OS. Idk if we'll need special support for this as guest admin can always arrange for grub.xen to land in right place by using tiny partition for this.