When determining if a device is behind a PCI bridge, the PCI device
class is checked by reading the config space. However, there are some
devices which have the wrong class on the config space, but the class is
initialized by Linux correctly as a PCI BRIDGE. This class can be read
by the sysfs file '/sys/bus/pci/devices/xxxx:xx:xx.x/class'.

One example of such bridge is IBM PCI Bridge 1014:03b9, which is
identified as a Host Bridge when reading the config space.
Signed-off-by: NThadeu Lima de Souza Cascardo <cascardo@linux.vnet.ibm.com>

'make distcheck' has been broken since commit 21685c95; basically,
it emulates the case of a read-only $(srcdir) (such as building
from a tarball exploded onto a CD-ROM), but we were creating our
fake pci device as a symlink into $(srcdir) and failing when that
requires opening the config file for writing:

 3) testVirPCIDeviceReset                                             ... libvirt:  error : Failed to open config space file '/sys/bus/pci/devices/0000:00:01.0/config': Permission denied

Fix it by copying rather than symlinking.

* tests/virpcimock.c (make_file): Add parameter to allow binary
creation; adjust all callers.
(pci_device_new_from_stub): Copy rather than symlink.
Signed-off-by: NEric Blake <eblake@redhat.com>

While trying to debug a failure of virpcitest during 'make distcheck',
I noticed that with a VPATH build, 'cd tests; ./virpcitest' fails for
an entirely different reason.  To reproduce the distcheck failure, I
had to run 'cd tests; abs_srcdir=/path/to/src ./virpcitest'.  But we
document in HACKING that all of our tests are supposed to be runnable
without requiring extra environment variables.

The solution: hardcode the location of srcdir into the just-built
binaries, rather than requiring make to prepopulate environment
variables.  With this, './virpcitest' passes even in a VPATH build
(provided that $(srcdir) is writable; a followup patch will fix the
conditions required by 'make distcheck').  [Note: the makefile must
still pass on directory variables to the test environment of shell
scripts, since those aren't compiled.  So while this solves the case
of a compiled test, it still requires environment variables to pass
a VPATH build of any shell script test case that relies on srcdir.]

* tests/Makefile.am (AM_CFLAGS): Define abs_srcdir in all compiled
tests.
* tests/testutils.h (abs_srcdir): Quit declaring.
* tests/testutils.c (virtTestMain): Rely on define rather than
environment variable.
* tests/virpcimock.c (pci_device_new_from_stub): Rely on define.
* tests/cputest.c (mymain): Adjust abs_top_srcdir default.
* tests/qemuxml2argvtest.c (mymain): Likewise.
* tests/qemuxmlnstest.c (mymain): Likewise.
Signed-off-by: NEric Blake <eblake@redhat.com>

This addition, however, requires some refactoring to be done.  First of
all, to match the best practice we should detach the device prior
resetting it. That's why testVirPCIDeviceDetach is detaching all devices
within 0000:00:01.0 and 0000:00:03.0 range. Then, the brand new test
will reset the 0000:00:02.0 device, so the last testVirPCIDeviceReattach
can reattach all the devices back.

In order to perform a PCI device reset, the dummy config file is not
sufficient anymore and must be replaced with real PCI config (binary
mess). Such config files are to be stored under tests/virpcitestdata/
and ought to have '.config' suffix.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

In the pci_driver_new function it is possible to set a list of
<vendor:device> IDs that the driver knows. These IDs are passed as
variable arguments and are processed  the usual way using va_start() and
va_arg(). However, after all arguments has been processed, we should
call va_end() what we aren't currently doing.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

This commit introduces yet another test under virpcitest:
virPCIDeviceDetach. However, in order to be able to do this, the
virpcimock needs to be extended to model the kernel behavior on PCI
device binding and unbinding (create 'driver' symlinks under the device
tree, check for device ID in driver's ID table, etc.)
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

Among with this test introduce virpcimock as we need to mock some
syscalls, e.g. redirect open() of a file under /sys/bus/pci to a
stub sysfs tree.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>