> -----Original Message----- > From: Jan Beulich [mailto:jbeul...@suse.com] > Sent: 27 March 2019 14:27 > To: Paul Durrant <paul.durr...@citrix.com> > Cc: xen-devel <xen-devel@lists.xenproject.org> > Subject: Re: [Xen-devel] xen disk spec and emulation > > >>> On 27.03.19 at 14:54, <paul.durr...@citrix.com> wrote: > > Currently, when specifying a virtual disk, the only way to determine the > > emulation model used is by selecting a particular 'vdev' numbering scheme as > > detailed in xl-disk-configuration in the docs. That document refers the > > reader to xen-vbd-interface which says: > > > > xvd* -> xen virtual disk (from which one infers PV-only) > > hd* -> IDE emulation > > sd* -> SCSI emulation > > d*p* -> unknown emulation > > > > The first choice actually results in IDE emulation, which is not stated > > anywhere AFAIK, and the fourth choice actually results in no emulation, > > although that's not stated either. These two things can, of course, be fixed > > in the documentation but I also think that the behaviour of vdev=xvd* is > > surprising and wrong. > > Wasn't this behavior intended to allow a guest to be installed > without PV drivers, but to have them enabled once they got > installed? >
I don't think so. AIUI that's what hd* and sd* were for. They seem to be the only vdev types that are documented to have emulated equivalents. I also appear to have been wrong about AHCI being completely undocumented. There is a line in xen-vbd-interface that specifies an extra 'hdtype=ahci' option, to add add ich9 controller emulation to the VM. Paul _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
