Stefan Hajnoczi <stefa...@gmail.com> writes: > On Wed, Mar 29, 2017 at 07:01:38PM -0700, Ed Swierk wrote: >> Parts of qemu's block code have changed a lot in recent months but are >> not well exercised by current tests. <snip> > > 4. How to automate tests with real Linux guests? This is a complex > topic and probably what we should discuss in this email thread. > > The buildroot + busybox approach is good for a small set of sanity > tests. There was a similar attempt here: > https://github.com/stsquad/qemu-jeos > > Building from source becomes a challenge when other people want to add > software to test other areas of QEMU. The process also requires > attention to maintain the image over time (e.g. as host build > environments change). > > There are image builder tools like virt-builder and mkosi for building > bootable virtual machine images based on standard Linux distros: > http://libguestfs.org/virt-builder.1.html > https://github.com/systemd/mkosi > > This eliminates the build-from-source hassles and gives us a full Linux > guest environment. Booting is very fast with mkosi so the advantage to > custom building a minimal image is negligible.
Does it entirely? If your building a ARM guest on x86 how do you ensure the cross-compilers are correct for the kernel and userspace? > My suggestion is: > > Let's pick an image builder tool like virt-builder and keep a single > build script per guest architecture (e.g. build-test-os-x86_64.sh). > All tests for that architecture run against the same disk image. > > It's easy to add additional software to the disk image by modifying the > build script. > > A Makefile ensures that the image file gets rebuilt if the build script > has changed. I have experimented building LTP for foreign guests inside docker images. I expect the docker build image could be extended to build full kernel and file-systems in a known environment, possibly using virt-builder to do it. > >> >> I made some minor changes to the test infrastructure so the new iotest >> can deal gracefully with qemu hanging--the test script itself >> shouldn't hang. And in all failure modes the test needs to expose >> enough console output and other information to diagnose the problem. >> >> The main departure from existing iotests is running a real guest. I >> used buildroot to generate a small (~4 MB) Linux kernel with built-in >> initrd containing a busybox-based userland. After the iotest launches >> qemu, the guest loops writing to the block device, while the test >> performs snapshot operations. >> >> I ran the new iotest on 3 qemu versions: 2.7.1, stable-2.8-staging and >> 2.9.0-rc2. The latter two fail several test cases, all >> iothread-enabled. Only 2.7.1 passes all the cases. >> >> Here is the code for the new iotest (I didn't dare email patches with >> a 4 MB blob): >> https://github.com/skyportsystems/qemu-1/commits/eswierk-iotests-2.7 >> https://github.com/skyportsystems/qemu-1/commits/eswierk-iotests-2.8 >> https://github.com/skyportsystems/qemu-1/commits/eswierk-iotests-2.9 >> >> And here is the buildroot I used to generate the guest Linux kernel+initrd: >> https://github.com/skyportsystems/buildroot-1/commits/qemu-iotests >> >> Please check out the code and try the new test--particularly anyone >> who can also help figure out these failures. (Note that since half the >> test cases use an iothread, /dev/kvm must be readable and writable.) >> >> * stable-2.8-staging >> - guest, virtio-blk, iothread, single snapshot create+commit: hang on >> quit (intermittent) >> - guest, virtio-blk, iothread, repeated snapshot create+commit: hang >> after 1 iteration >> - guest, virtio-scsi, iothread, single snapshot create+commit: hang on >> quit (intermittent) >> - guest, virtio-scsi, iothread, repeated snapshot create+commit: hang >> after 1 iteration >> >> * 2.9.0-rc2 >> - guest, virtio-blk, iothread, single snapshot create+commit: >> "include/block/aio.h:457: aio_enable_external: Assertion >> `ctx->external_disable_cnt > 0' failed." after snapshot create >> - guest, virtio-blk, iothread, repeated snapshot create+commit: same as above >> - guest, virtio-scsi, iothread, single snapshot create+commit: same as above >> - guest, virtio-scsi, iothread, repeated snapshot create+commit: same as >> above >> - no guest, virtio-blk, iothread, repeated snapshot create+commit: same as >> above >> - no guest, virtio-scsi, iothread, single snapshot create+commit: same as >> above >> - no guest, virtio-scsi, iothread, repeated snapshot create+commit: >> same as above >> >> --Ed >> -- Alex Bennée
