Daniel P. Berrangé wrote:
On Tue, Oct 06, 2020 at 06:51:52PM +0400, Roman Bogorodskiy wrote:
Hi,
Recently bhyve got virtio-9p support. Modeling it appears to be pretty straight-forward, but probably I'm missing something, so decided to discuss first before proceeding with the implementation.
On the host side it looks like this:
bhyve .... -s 25:0,virtio-9p,distfiles=/workspace/distfiles
Mounting it in a (Linux) guest looks this way:
mount -t 9p distfiles /mnt/distfiles
lspci(8) shows it like this:
00:1f.0 SCSI storage controller: Red Hat, Inc. Virtio filesystem Subsystem: Red Hat, Inc. Virtio filesystem Flags: bus master, fast devsel, latency 64, IRQ 20 I/O ports at 2200 [size=512] Memory at c2004000 (32-bit, non-prefetchable) [size=8K] Expansion ROM at c0007000 [virtual] [disabled] [size=2K] Capabilities: [40] MSI-X: Enable+ Count=2 Masked- Capabilities: [4c] MSI: Enable- Count=1/1 Maskable- 64bit+ Kernel driver in use: virtio-pci
I was thinking about presenting it like this:
<filesystem type='mount'> <driver type='virtiofs'/>
This driver type is for virtio-fuse, which is different from virtio-9p. In QEMU we support type=path and type=handle as two different QEMU bakends for 9p. Or simply omit "type" entirely and it defaults to 9p in QEMU. So I think you can just omit "type" for bhyve too.
<source dir='/workspace/distfiles'> <target dir='distfiles'/> </filesystem>
There's also an optional <readonly/> element for readonly mounts, which is also supported by bhyve.
Yep.
Also consider the "accessmode" attribute - you'll want to validate whichever value(s) of that make sense given the bhyve impl of 9p.
It looks like the bhyve implementation doesn't do any uid/gid remapping, i.e. if I chown file on the host, I see same numeric ids (but they corresponding to different users/groups on my test Linux guest compared to the FreeBSD host). The same happens when I chown files in the guest and verify results in the host. Sounds like 'passthrough' is the right choice for this behavior?
Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
Roman Bogorodskiy