Question about transferring files to ARM Linux in Gem5 full-system mode

Question

I was running Linux in an ARM-based detailed CPU model in FS mode, and I was doing the checkpoint after the first time I launched the CPU. However, I needed to frequently transfer files to the ARM Linux, so I am wondering if there is any way to do so without re-launching the CPU model again (e.g., directly transfer files to linux through sftp, or mounting the host file system)? Great thanks!

Currently, I just added the files to the Linux disk image, and relaunched the CPU model from scratch (which takes more than 1.5 hours).

Answer 1

Here are the possibilities that I'm aware of:

• use 9P. Semi outdated patch at: http://gem5.org/WA-gem5 but easy to get working again.

  9P is designed explicitly to mount host directories on guest, and is therefore the nicest solution.

  See also: https://github.com/cirosantilli2/gem5-issues/issues/24

  QEMU example.

• use a second disk image, normally squashfs which is easy to generate quickly and conveniently.

  unmount, make changes to image, remount. So a bit annoying, but doable, and possibly the easiest to get working.

  Not currently exposed on fs.py, patch mentioned at: How to attach multiple disk images in a simulation with gem5 fs.py?

• m5 readfile + zip.

  OK, this is likely going to be slow, just mentioning it ;-)

• guest to host networking: as you mentioned, if that were possible, you could mount FTPs around

  However I don't think it is supported, see: How to do port forwarding from guest to host and vice versa in gem5?

  Also it would require messing with NFS setups on host / guest, which is always a bad thing.

  With QEMU, as usual, it is possible.

The current situation is a mess. The main reason is that it is a bit hard to nicely integrate 9P / multidisk into fs.py. But I'm certain it is possible, we just need a brave soul.

Related thread about how to expand an existing disk image if space is your concern: https://www.mail-archive.com/gem5-users@gem5.org/msg16494.html

Mailing list thread: https://www.mail-archive.com/gem5-users@gem5.org/msg16477.html