Re: File sharing over virtio-9p

[Ryota Ozaki <ozaki.ryota%gmail.com@localhost>]

On Tue, May 21, 2019 at 1:39 PM Ryota Ozaki <ozaki-r%netbsd.org@localhost> wrote:
>
> Hi,
>
> The following two patches enables a NetBSD guest running
> on a Linux KVM to share files with its host over virtio-9p.
>
>   https://www.netbsd.org/~ozaki-r/vio9p.diff
>   https://www.netbsd.org/~ozaki-r/mount_9p-cdev.diff
>
> The first patch exports a 9p endpoint of virtio-9p via a character
> device (e.g., /dev/vio9p0) and the second one extends mount_9p
> (puffs) to talk with a 9p server inside qemu via the character device.
>
> [Usage]
>
> Export a directory of a host via virtio-9p.  The below XML is part of
> a libvirt domain configuration.  It exports "/var/lib/libvirt/export"
> directory with a tag "test".  If it is the first entry, it will have
> minor number 0 and /dev/vio9p0 is assigned to it typically.
>
>     <filesystem type='mount' accessmode='mapped'>
>       <source dir='/var/lib/libvirt/export'/>
>       <target dir='test'/>
>       <address type='pci' domain='0x0000' bus='0x00' slot='0x03'
> function='0x0'/>
>     </filesystem>
>
> A boot log of vio9p looks like this:
>
>     virtio0 at pci0 dev 3 function 0
>     virtio0: Virtio 9P Transport Device (rev. 0x00)
>     vio9p0 at virtio0: Features: 0x10000000<INDIRECT_DESC>
>     virtio0: allocated 12288 byte for virtqueue 0 for vio9p, size 128
>     virtio0: using 4096 byte (256 entries) indirect descriptors
>     vio9p0: tagged as test
>     virtio0: interrupting at ioapic0 pin 11
>
> A NetBSD guest can mount the exported directory with mount_9p.
>
>     mount_9p -cu /dev/vio9p0 /mnt/9p
>
> -c tells mount_9p to interpret the first argument as a character
> device file to talk with.
>
>
> Have fun,
>   ozaki-r

I've prepared complete patches ready to commit:
  https://www.netbsd.org/~ozaki-r/tweak-MAKEDEV.diff
  https://www.netbsd.org/~ozaki-r/vio9p.diff
  https://www.netbsd.org/~ozaki-r/vio9p-configs.diff
  https://www.netbsd.org/~ozaki-r/mount_9p-cdev.diff

Any comments?

I would like to commit them in several days if there is
no objection.

Regards,
  ozaki-r