Add a new generic fuzz target for the 'pcie-pci-bridge' device. This
target uses a Q35 machine with a multi-level PCI hierarchy to exercise
the bridge's functionality.
This is made possible by the preceding change to handle unimplemented
BARs during fuzzing.

---

This new target significantly improves code coverage for the pcie-pci-bridge
implementation. The baseline coverage shown below was generated by
running all existing fuzz targets with the oss-fuzz corpus.

=== Component: hw/pci  ===
-------------------------------------------------------------------------------
File                           New Target           Baseline             Change
-------------------------------------------------------------------------------
shpc.c                         359/511 (70.3%)      0/511 (0.0%)         +359
pci_bridge.c                   255/304 (83.9%)      12/304 (3.9%)        +243
pcie.c                         390/774 (50.4%)      160/774 (20.7%)      +230
pcie_aer.c                     119/524 (22.7%)      38/524 (7.3%)        +81
pci.c                          1154/2069 (55.8%)    1084/2069 (52.4%)    +70
pcie_port.c                    58/119 (48.7%)       17/119 (14.3%)       +41
pci.h                          86/132 (65.2%)       81/132 (61.4%)       +5

=== Component: hw/pci-bridge  ===
-------------------------------------------------------------------------------
File                           New Target           Baseline             Change
-------------------------------------------------------------------------------
pcie_root_port.c               86/127 (67.7%)       13/127 (10.2%)       +73
pcie_pci_bridge.c              62/94 (66.0%)        20/94 (21.3%)        +42
gen_pcie_root_port.c           45/66 (68.2%)        19/66 (28.8%)        +26

Signed-off-by: Navid Emamdoost <navidem@google.com>
---
 tests/qtest/fuzz/generic_fuzz_configs.h | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/tests/qtest/fuzz/generic_fuzz_configs.h b/tests/qtest/fuzz/generic_fuzz_configs.h
index ef0ad95712..e025f57a3e 100644
--- a/tests/qtest/fuzz/generic_fuzz_configs.h
+++ b/tests/qtest/fuzz/generic_fuzz_configs.h
@@ -247,6 +247,14 @@ const generic_fuzz_config predefined_configs[] = {
         .args = "-machine q35 -nodefaults "
         "-parallel file:/dev/null",
         .objects = "parallel*",
+    },{
+        .name = "pcie-pci-bridge",
+        .args = "-machine q35 -nodefaults "
+        "-device pcie-root-port,port=0x10,chassis=1,id=pci.1,bus=pcie.0,multifunction=true,addr=0x2 "
+        "-device pcie-pci-bridge,id=pci.2,bus=pci.1,addr=0x0 "
+        "-netdev user,id=net0 "
+        "-device e1000,netdev=net0,id=nic0,bus=pci.2,addr=0x3",
+        .objects = "pci* shpc*"
     }
 };
 
-- 
2.52.0.158.g65b55ccf14-goog