Re: [Qemu-devel] [PATCH v2 for-2.11 0/2] Improvements for the pxe tester

[Cornelia Huck <cohuck@redhat.com>]

On Fri, 11 Aug 2017 07:57:54 +0200
Thomas Huth <thuth@redhat.com> wrote:

> The first patch improves the buffer handling in the pxe tester a
> little bit by allocating a separate buffer on the heap for each
> architecture. This also gets rid of the huge pre-initialized
> array in the tester, shrinking the size of the executable by
> half of a megabyte!
> The second patch adds s390x support to the pxe tester. Starting
> with QEMU 2.10, the guest firmware on s390x can now net-boot via
> TFTP, too, so we can automatically test this code in the pxe tester.
> 
> v2: Adressed Cornelia's review feedback from the first version, e.g.:
>  - Use g_malloc0() instead of g_malloc()
>  - Use sizeof with parentheses
> 
> Thomas Huth (2):
>   tests/boot-sector: Do not overwrite the x86 buffer on other
>     architectures
>   tests/pxe: Check virtio-net-ccw on s390x
> 
>  tests/Makefile.include |  1 +
>  tests/boot-sector.c    | 61 +++++++++++++++++++++++++++++++++++++-------------
>  tests/pxe-test.c       |  7 ++++++
>  3 files changed, 54 insertions(+), 15 deletions(-)
> 

Haven't reviewed the updates yet, but tried it out (on my laptop and on
a z/VM guest). Laptop went fine; on the z/VM guest, I forgot to turn on
vm.allocate_pgste at first:

TEST: tests/pxe-test... (pid=56084)
  /s390x/pxe/virtio-ccw:                                               ioctl(KVM_CREATE_VM) failed: 22 Invalid argument
Host kernel setup problem detected. Please verify:
- for kernels supporting the switch_amode or user_mode parameters, whether
  user space is running in primary address space
- for kernels supporting the vm.allocate_pgste sysctl, whether it is enabled
qemu-system-s390x: failed to initialize KVM: Invalid argument
qemu-system-s390x: Back to tcg accelerator
OK
PASS: tests/pxe-test

It does the correct fallback (the need for allocate_pgste will go away
with future kernels), so this is fine. However, it prompted me to test
with --disable-tcg:

TEST: tests/boot-serial-test... (pid=60499)
  /s390x/boot-serial/s390-ccw-virtio:                                  qemu-system-s390x: -machine accel=tcg: No accelerator found
socket_accept failed: Resource temporarily unavailable
**
ERROR:/root/git/qemu/tests/libqtest.c:212:qtest_init_without_qmp_handshake: assertion failed: (s->fd >= 0 && s->qmp_fd >= 0)
FAIL
GTester: last random seed: R02S83c8a1860bbd8c2658647407c7070b7e
(pid=60503)
FAIL: tests/boot-serial-test

There are probably more tests that rely on tcg always being available,
which is no longer true. (Also, the boot-serial test should probably
check if qemu even started rather than run into in a timeout.)

[Your patches are fine, but I think we really need to consider tests
and accelerators.]