[Qemu-devel] [PATCH v3 1/3] pcie aer: verify if AER functionality is available

[Cao jin]

For devices which support AER function, verify it can work or not in the
system:
1. AER capable device is a PCIe device, it can't be plugged into PCI bus
2. If root port doesn't support AER, then there is no need to expose the
   AER capability

Signed-off-by: Dou Liyang <address@hidden>
Signed-off-by: Cao jin <address@hidden>
---
 hw/pci/pcie_aer.c | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/hw/pci/pcie_aer.c b/hw/pci/pcie_aer.c
index daf1f65..a2e9818 100644
--- a/hw/pci/pcie_aer.c
+++ b/hw/pci/pcie_aer.c
@@ -100,6 +100,34 @@ static void aer_log_clear_all_err(PCIEAERLog *aer_log)
 int pcie_aer_init(PCIDevice *dev, uint8_t cap_ver, uint16_t offset,
                   uint16_t size, Error **errp)
 {
+    PCIDevice *parent_dev;
+    uint8_t type;
+    uint8_t parent_type;
+
+    /* Topology test: see if there is need to expose AER cap */
+    type = pcie_cap_get_type(dev);
+    parent_dev = pci_bridge_get_device(dev->bus);
+    while (parent_dev) {
+        parent_type = pcie_cap_get_type(parent_dev);
+
+        if (type == PCI_EXP_TYPE_ENDPOINT &&
+                (parent_type != PCI_EXP_TYPE_ROOT_PORT &&
+                 parent_type != PCI_EXP_TYPE_DOWNSTREAM)) {
+            error_setg(errp, "Parent device is not a PCIe component");
+            return -ENOTSUP;
+        }
+        
+        if (parent_type == PCI_EXP_TYPE_ROOT_PORT) {
+            if (!parent_dev->exp.aer_cap)
+            {
+                error_setg(errp, "Root port does not support AER");
+                return -ENOTSUP;
+            }
+        }
+
+        parent_dev = pci_bridge_get_device(parent_dev->bus);
+    }
+
     pcie_add_capability(dev, PCI_EXT_CAP_ID_ERR, cap_ver,
                         offset, size);
     dev->exp.aer_cap = offset;
-- 
1.8.3.1