[PATCH v3] pci: correct pci config size default for cap version 2 endpoints

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v3: remove all boundary tests. just fix the obvious bug.
  : boundary test is not necessary; get this fix in &
    post boundary test in another separate patch.
    
v2: do local boundary check with respect to legacy PCI header length,
    and don't depend on it in pci_add_capability().
  : fix compilation, and change else>2 to simple else for all other cases.

v1: first patch: boundary check in pci_add_capability().

Doing device assignement using a PCIe device with it's
PCI Cap structure at offset 0xcc showed a problem in
the default size mapped for this cap-id.

The failure caused a corruption which might have gone unnoticed
otherwise.

Fix assigned_device_pci_cap_init() to set the default
size of PCIe Cap structure (cap-id 0x10) to 0x34 instead of 0x3c.
0x34 is default, min, for endpoint device with a cap version of 2.

Signed-off-by: Donald Dutile <ddutile@xxxxxxxxxx>
cc: Alex Williamson <alex.williamson@xxxxxxxxxx>
cc: Michael S. Tsirkin <mst@xxxxxxxxxx>

tested-by: ebenes@xxxxxxxxxx

---

 hw/device-assignment.c |    8 +++++---
 1 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/hw/device-assignment.c b/hw/device-assignment.c
index 36ad6b0..34db52e 100644
--- a/hw/device-assignment.c
+++ b/hw/device-assignment.c
@@ -1419,16 +1419,18 @@ static int assigned_device_pci_cap_init(PCIDevice *pci_dev)
     }
 
     if ((pos = pci_find_cap_offset(pci_dev, PCI_CAP_ID_EXP, 0))) {
-        uint8_t version;
+        uint8_t version, size;
         uint16_t type, devctl, lnkcap, lnksta;
         uint32_t devcap;
-        int size = 0x3c; /* version 2 size */
 
         version = pci_get_byte(pci_dev->config + pos + PCI_EXP_FLAGS);
         version &= PCI_EXP_FLAGS_VERS;
         if (version == 1) {
             size = 0x14;
-        } else if (version > 2) {
+        } else if (version == 2) {
+            /* don't include slot cap/stat/ctrl 2 regs; only support endpoints */
+            size = 0x34;
+        } else {
             fprintf(stderr, "Unsupported PCI express capability version %d\n",
                     version);
             return -EINVAL;

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