Re: [DistroKit] [PATCH] x86_64: run: add 9p support

["Jan Lübbe" <jlu@pengutronix.de>]

On Wed, 2023-03-01 at 20:24 +0100, Michael Grzeschik wrote:
> On Wed, Mar 01, 2023 at 04:55:34PM +0100, Robert Schwebel wrote:
> > On Tue, Jan 31, 2023 at 07:50:40AM +0100, Jan Lübbe wrote:
> > > On Mon, 2023-01-30 at 23:03 +0100, Michael Grzeschik wrote:
> > > > copy the qemu 9p rule from platform v7a and make 9p the default
> > > > 
> > > > Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
> > > > ---
> > > >  configs/platform-x86_64/run | 23 ++++++++++++++++++++++-
> > > >  1 file changed, 22 insertions(+), 1 deletion(-)
> > > > 
> > > > diff --git a/configs/platform-x86_64/run b/configs/platform-x86_64/run
> > > > index c39d5a7b..96322292 100755
> > > > --- a/configs/platform-x86_64/run
> > > > +++ b/configs/platform-x86_64/run
> > > > @@ -67,6 +67,12 @@ fi
> > > > 
> > > >  BASE_CMDLINE="console=ttyS0,115200 loglevel=5 systemd.log_level=warning systemd.show_status=auto"
> > > > 
> > > > +if [ -d "${PTXDIST_PLATFORMDIR}/root/.virtfs_metadata" ]; then
> > > > +	security_model="mapped-file"
> > > > +else
> > > > +	security_model="none"
> > > > +fi
> > > > +
> > > >  # Machine to emulate
> > > >  QEMU_ARGS=( -L ${PTXDIST_PLATFORMDIR}/sysroot-host/share/qemu/ -machine pc-q35-2.12 -smp 2 -cpu host -accel kvm -m 1G -s )
> > > >  # disable graphics output
> > > > @@ -97,7 +103,22 @@ run_qemu_hda() {
> > > >  		-append "root=/dev/vda console=ttyS0,115200 rw ${BASE_CMDLINE}"
> > > >  }
> > > > 
> > > > -target="${1:-hda}"
> > > > +#
> > > > +# This needs:
> > > > +# CONFIG_NET_9P_VIRTIO=y
> > > > +# CONFIG_9P_FS=y
> > > > +#
> > > > +run_qemu_9p() {
> > > > +	exec ${QEMU_EXEC} \
> > > > +		"${QEMU_ARGS[@]}" \
> > > > +		-fsdev local,id=rootfs,path=${PTXDIST_PLATFORMDIR}/root,security_model="${security_model}" \
> > > > +		-device virtio-9p-pci,fsdev=rootfs,mount_tag=/dev/root \
> > > > +		"${QEMU_EXTRA_ARGS[@]}" \
> > > > +		"${QEMU_LINUX_ARGS[@]}" \
> > > > +		-append "root=/dev/root rw rootfstype=9p rootflags=trans=virtio ${BASE_CMDLINE}"
> > > 
> > > You should set msize explicitly do make it less likely that some userspace tools
> > > are confused by short reads from 9pfs (nginx for example).
> > 
> > Care to re-send?
> 
> Sure! But:
> 
> @jluebbe: I found your discussion about setting explicit msize in the
> qemu virtio parameters.
> 
> https://gitlab.com/qemu-project/qemu/-/issues/409
> 
> However I did not find out which reasonable value to set from the
> thread, since the discussion is talking about different causes to
> trigger the issues. e.g. tar without O_PARTIAL in the kernel headers.
> 
> Would msize=104857600 be something to work with?

We use 16777216 in RAUC testing to fix issues with nginx, which seems to be the
maximum in the kernel. That has been working fine for two years.

Jan

> I also found some patches that are there to solve the issue probably,
> but they got not mainlined yet.
> 
> https://lore.kernel.org/netdev/cover.1640870037.git.linux_oss@crudebyte.com/
> 
> mgr
> 
> > > > +}
> > > > +
> > > > +target="${1:-9p}"
> > > > 
> > > >  #set -x
> > > >  run_qemu_${target}
> > 
> > rsc
> > -- 
> > Pengutronix e.K.                           | Dipl.-Ing. Robert Schwebel  |
> > Steuerwalder Str. 21                       | https://www.pengutronix.de/ |
> > 31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
> > Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-9    |
> > 
> 

-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
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