[Qemu-devel] [PATCH] pci: Error on PCI capability collisions

[Jan Kiszka <jan.kiszka@siemens.com>]

From: Alex Williamson <alex.williamson@redhat.com>

Nothing good can happen when we overlap capabilities

[ Jan: rebased over qemu, minor formatting ]

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
---
 hw/pci.c |   14 ++++++++++++++
 1 files changed, 14 insertions(+), 0 deletions(-)

diff --git a/hw/pci.c b/hw/pci.c
index 6124790..ff20631 100644
--- a/hw/pci.c
+++ b/hw/pci.c
@@ -1952,11 +1952,25 @@ int pci_add_capability(PCIDevice *pdev, uint8_t cap_id,
                        uint8_t offset, uint8_t size)
 {
     uint8_t *config;
+    int i;
+
     if (!offset) {
         offset = pci_find_space(pdev, size);
         if (!offset) {
             return -ENOSPC;
         }
+    } else {
+        for (i = offset; i < offset + size; i++) {
+            if (pdev->used[i]) {
+                fprintf(stderr, "ERROR: %04x:%02x:%02x.%x "
+                        "Attempt to add PCI capability %x at offset "
+                        "%x overlaps existing capability %x at offset %x\n",
+                        pci_find_domain(pdev->bus), pci_bus_num(pdev->bus),
+                        PCI_SLOT(pdev->devfn), PCI_FUNC(pdev->devfn),
+                        cap_id, offset, pdev->config_map[i], i);
+                return -EFAULT;
+            }
+        }
     }
 
     config = pdev->config + offset;
-- 
1.7.3.4