On Wed, 13 Sep 2017 15:27:51 +0200
Halil Pasic <pa...@linux.vnet.ibm.com> wrote:
> Add a fake device meant for testing the correctness of our css emulation.
>
> What we currently have is writing a Fibonacci sequence of uint32_t to the
> device via ccw write. The write is going to fail if it ain't a Fibonacci
> and indicate a device exception in scsw together with the proper residual
> count.
>
> Of course lot's of invalid inputs (besides basic data processing) can be
> tested with that as well.
>
> Usage:
> 1) fire up a qemu with something like -device ccw-tester,devno=fe.0.0001
> on the command line
> 2) exercise the device from the guest
>
> Signed-off-by: Halil Pasic <pa...@linux.vnet.ibm.com>
> ---
>
> Depends on the series 'add CCW indirect data access support'
>
> ---
> hw/s390x/Makefile.objs | 1 +
> hw/s390x/ccw-tester.c | 179
> +++++++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 180 insertions(+)
> create mode 100644 hw/s390x/ccw-tester.c
>
> +static int ccw_tester_write_fib(SubchDev *sch, CCW1 ccw)
> +{
> + CcwTesterDevice *d = sch->driver_data;
> + bool is_fib = true;
> + uint32_t sum;
> + int ret = 0;
> +
> + ccw_dstream_init(&sch->cds, &ccw, &sch->orb);
> + d->fib.next = 0;
> + while (ccw_dstream_avail(&sch->cds) > 0) {
> + ret = ccw_dstream_read(&sch->cds,
> + d->fib.ring[abs_to_ring(d->fib.next)]);
> + if (ret) {
> + error(0, -ret, "fib");
> + break;
> + }
> + if (d->fib.next > 2) {
> + sum = (d->fib.ring[abs_to_ring(d->fib.next - 1)]
> + + d->fib.ring[abs_to_ring(d->fib.next - 2)]);
> + is_fib = sum == d->fib.ring[abs_to_ring(d->fib.next)];
This is not endian-safe (noticed while testing on my laptop). Trivial
to fix:
diff --git a/hw/s390x/ccw-tester.c b/hw/s390x/ccw-tester.c
index c8017818c4..a425daaa34 100644
--- a/hw/s390x/ccw-tester.c
+++ b/hw/s390x/ccw-tester.c
@@ -58,9 +58,9 @@ static int ccw_tester_write_fib(SubchDev *sch, CCW1 ccw)
break;
}
if (d->fib.next > 2) {
- sum = (d->fib.ring[abs_to_ring(d->fib.next - 1)]
- + d->fib.ring[abs_to_ring(d->fib.next - 2)]);
- is_fib = sum == d->fib.ring[abs_to_ring(d->fib.next)];
+ sum = be32_to_cpu(d->fib.ring[abs_to_ring(d->fib.next - 1)])
+ + be32_to_cpu(d->fib.ring[abs_to_ring(d->fib.next - 2)]);
+ is_fib = sum == be32_to_cpu(d->fib.ring[abs_to_ring(d->fib.next)]);
if (!is_fib) {
break;
}
> + if (!is_fib) {
> + break;
> + }
> + }
> + ++(d->fib.next);
> + }
> + if (!is_fib) {
> + sch->curr_status.scsw.ctrl &= ~SCSW_ACTL_START_PEND;
> + sch->curr_status.scsw.ctrl |= SCSW_STCTL_PRIMARY |
> + SCSW_STCTL_SECONDARY |
> + SCSW_STCTL_ALERT |
> + SCSW_STCTL_STATUS_PEND;
> + sch->curr_status.scsw.count = ccw_dstream_residual_count(&sch->cds);
> + sch->curr_status.scsw.cpa = sch->channel_prog + 8;
> + sch->curr_status.scsw.dstat = SCSW_DSTAT_UNIT_EXCEP;
> + return -EIO;
> + }
> + return ret;
> +}
> +
(...)
> +static Property ccw_tester_properties[] = {
> + DEFINE_PROP_UINT16("cu_type", CcwTesterDevice, cu_type,
> + 0x3831),
0x4711 would be nice :)
If we want to follow up on that testdev idea (and I think we should),
it might make sense to have a proper type reserve to prevent accidental
clashes.
(Or is there already something reserved for "hypervisor use" or
whatever?)
> + DEFINE_PROP_UINT8("chpid_type", CcwTesterDevice, chpid_type,
> + 0x98),
> + DEFINE_PROP_END_OF_LIST(),
> +};
IIUC, pci-testdev provides some unit tests to testers (like kvm-tests)
itself. This might be an idea to follow up on for ccw as well.
There's quite some potential in this. We may want to make this a
permanent addition.
