Il 09/03/2012 08:46, Gerhard Wiesinger ha scritto: > On Fri, 9 Mar 2012, Gerd Hoffmann wrote: > >> Hi, >> >>>>> #2 isn't an issue actually, at least for Debian users -- >>>> >>>> Well, it is, to some degree. Because vanilla upstream doesn't support >>>> booting from lsi it has alot less users and alot less regression >>>> testing >>>> (like autotest runs of lsi-scsi installs), which sums up to more bugs >>>> staying unnoticed like the one which triggered this thread. >>> >>> What's the holdup to integrate it into QEMU? >> >> Extboot is considered obsolete and thus several attempts to merge it >> into upstream qemu failed. It started its life as hack to allow >> qemu-kvm boot from virtio-blk devices, which happened to work for lsi >> too. virtio-blk is supported by seabios natively these days. >> >> Adding lsi support to seabios shouldn't be that hard. Paolo paved the >> way by restructing the existing scsi disk/cdrom bits in seabios so they >> work for both usb-storage and virtio-scsi. Adding support for yet >> another scsi hba should be easy, all the support bits for handling disks >> and booting from cdrom are there already. >> >> It just needs someone to sit down for a week or two and hack it up. > > @Paolo: Would that be easily possible?
Sure. You could expect the SeaBIOS driver to be 700-100 lines of code: $ wc lsi53c895a.c virtio-scsi.c usb-msd.c # in QEMU 2150 6959 62694 lsi53c895a.c 617 1537 18463 virtio-scsi.c 677 1847 18465 usb-msd.c $ wc virtio-scsi.c usb-msc.c # in SeaBIOS 177 517 4711 virtio-scsi.c 174 499 4935 usb-msc.c As Gerd said, the SCSI layer is entirely abstracted (the only piece missing to abstract is discovery, which is why virtio-scsi will only boot from LUN0). The driver only needs to provide a way to execute CDBs. > BTW: What do you think anout that: > Handling INT13h always directly through virtio-scsi regardless of > selected SCSI adapter, or when OS driver is loaded through SCSI adapter, > so just have 2 ways to the disks: > 1.) Through INT13h to virtio-scsi and then to the disks > 2.) Through SCSI adapter and then to the disks (OS driver loaded) Interesting idea. :) That would work, I guess. By the way, you said the lsi53c is buslogic in VMWare and hence libvirt? Paolo
