Re: [Qemu-devel] Using virtio-mmio

[Richard W.M. Jones]

On Thu, Aug 01, 2013 at 11:58:15AM +0100, Peter Maydell wrote:
> Unfortunately at this point you run into the classic
> issue of trying to get an ARM kernel running, which
> is that a huge class of config errors all have the
> failure mode "just sits there with no serial output".
> This is remarkably user-unfriendly but I don't really
> know how we could fix it since the underlying cause
> is that serial ports on ARM aren't in a single standard
> location, so if the kernel's not configured right it
> won't find the serial port. I usually end up resorting
> to running with gdb connected to qemu's debug stub
> and fishing the kernel output out of its log_buf :-(

Yeah, probably I should fix virt-dmesg to work on ARM guests ...

I don't know if there's a better list for asking these questions, but
here's another one:

~/d/qemu/arm-softmmu/qemu-system-arm -m 512 -M vexpress-a9 \
  -kernel kernel -initrd initrd \
  -drive if=none,file=root,id=foo -device virtio-blk-device,drive=foo \
  -append "root=/dev/vda console=ttyAMA0 rootwait debug" -serial stdio

This command boots the kernel, loads the initrd, and loads the virtio
modules, but the 'root' disk is never enumerated (see full messages
attached).

I wonder if I'm missing a kernel module for virtio-blk to work?

The code that is running in the guest is here if you're interested:
https://github.com/libguestfs/supermin/blob/master/helper/init.c

---

I'd _really_ prefer to use virtio-scsi, since virtio-blk has all sorts
of shortcomings.  However I could work out the command line fu to
enable virtio-scsi.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
virt-df lists disk usage of guests without needing to install any
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http://people.redhat.com/~rjones/virt-df/

qemu-boot.txt
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