Date: Tue, 19 Jun 2012 02:40:44 -0500 (CDT) From: Bryan Venteicher <bryanv@daemoninthecloset.org> To: freebsd-scsi@freebsd.org Cc: freebsd-virtualization@freebsd.org Subject: Re: [CFT] VirtIO SCSI Driver Message-ID: <1449819169.793.1340091643925.JavaMail.root@sage.daemoninthecloset.org> In-Reply-To: <608701174.2086.1339136958852.JavaMail.root@sage.daemoninthecloset.org>
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Hi,
----- Original Message -----
> From: "Bryan Venteicher" <bryanv@daemoninthecloset.org>
> To: freebsd-scsi@freebsd.org
> Cc: freebsd-virtualization@freebsd.org
> Sent: Friday, June 8, 2012 1:29:18 AM
> Subject: [CFT] VirtIO SCSI Driver
>
> Hi,
>
> VirtIO SCSI is a virtualized HBA that offers a couple of advantages
> over the existing VirtIO block disk devices. Instead of having a
> vtbdX disk, familiar daX and cdX devices are created like from other
> SCSI drivers. A single HBA is able to support multiple devices unlike
> the VirtIO block where there is one disk per PCI device. And SCSI
> devices from the host are able to be passthrough to the guest.
>
A second patch is available at:
www.daemoninthecloset.org/~bryanv/patches/freebsd/freebsd_virtio_scsi_2.patch
Most of the changes are just cleanup; the only noteworthy fix is that
CAM_SCSI_STATUS_ERROR is now reported correctly. With a QEMU patch
provided by the VirtIO SCSI author, bus reset now works. I hope the
patch is committed soon upstream to QEMU.
As I mentioned in my previous email, you need a QEMU with VirtIO SCSI
support. You can check if your QEMU has the support by:
$ qemu -device ?
and looking for a line like:
name "virtio-scsi-pci", bus PCI
VirtIO SCSI should be supported by QEMU 1.1 or later. If your
distribution does not provide a new enough QEMU, you'll need to compile
from source.
You'll then need to have QEMU create a VirtIO SCSI disk for the guest.
The CLI sugar to do this is a bit ugly, but will look like:
-drive file=/vm_images/vtscsi-2.img,if=none,id=drive-scsi0-0-0 \
-device virtio-scsi-pci,id=scsi0,bus=pci.0,addr=0x6 \
-device scsi-disk,bus=scsi0.0,scsi-id=0,drive=drive-scsi0-0-0,id=scsi0-0-0
AFAIK, this really isn't documented anywhere (the QEMU man page isn't at
all helpful) and took a bit of guessing when I was first getting started
with it.
Bryan
>
> Should apply cleanly to any recent -current, and probably to a
> -stable
> with minimal work.
>
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