Re: [V9fs-developer] [Qemu-devel] QEMU dies on any attempt to load a Linux kernel module when using a 9P rootfs

Hi Dominique,

On 08/22/2014 08:49 AM, Dominique Martinet wrote:

Hi,

Christopher Covington wrote on Fri, Aug 22, 2014 at 08:37:52AM -0400:

quoted

Thanks for the pointer to this patch. I think I started this kernel half way
through the 3.16 merge window. The last non-cherry-picked patch I have is:

commit 6d87c225f5d82d29243dc124f1ffcbb0e14ec358

So I do have the change you pointed out. Nevertheless, I'll reconfirm with the
latest torvalds/master.

Right, so you already do have it. I don't think there's been anything
else 9P related recently, so it probably will not help much -- sorry for
blindly assuming it would be this.

Actually reading the error message now, "no channels available" is
printed when virtio doesn't find any match in device name so it would
look like the mount name doesn't match maybe?

Could we get your exact qemu command line to confirm? (the name that
needs to match is /dev/root here, used for booting as root= and for qemu
as mount_tag)

I re-transposed Richard's command line to my environment and it worked. Thanks
for pointing me in that direction. For the record, I used:

$dir/bin/x86_64-linux-gnu/qemu-system-x86_64 \
  -m 1024 \
  -kernel $dir/boot/x86_64-linux-gnu/bzImage-x86_64 \
  -append 'root=/dev/root init=/sbin/x86_64-linux-gnu/init rootfstype=9p
rootflags=trans=virtio,version=9p2000.L ro console=ttyS0' \
  -serial stdio \
  -fsdev local,id=root,path=$dir,security_model=none \
  -device virtio-9p-pci,fsdev=root,mount_tag=/dev/root \
  -monitor none

$dir/bin/x86_64-linux-gnu/qemu-system-arm \
  -M virt \
  -cpu cortex-a15 \
  -m 1024 \
  -kernel $dir/boot/arm-linux-gnueabihf/Image \
  -append 'root=/dev/root init=/sbin/arm-linux-gnueabihf/init rootfstype=9p
rootflags=trans=virtio,version=9p2000.L ro console=ttyAMA0' \
  -serial stdio \
  -fsdev local,id=root,path=$dir,security_model=none \
  -device virtio-9p-device,fsdev=root,mount_tag=/dev/root \
  -monitor none

$dir/bin/x86_64-linux-gnu/qemu-system-aarch64 \
  -M virt \
  -cpu cortex-a57 \
  -m 1024 \
  -kernel $dir/boot/aarch64-linux-gnu/Image \
  -append 'root=/dev/root init=/sbin/aarch64-linux-gnu/init rootfstype=9p
rootflags=trans=virtio,version=9p2000.L ro console=ttyAMA0' \
  -serial stdio \
  -fsdev local,id=root,path=$dir,security_model=none \
  -device virtio-9p-device,fsdev=root,mount_tag=/dev/root -monitor none

Christopher

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