[PATCH v3 03/11] vpci/header: Emulate legacy capability list for dom0

[Jiqian Chen <Jiqian.Chen@xxxxxxx>]

Current logic of emulating legacy capability list is only for domU.
So, expand it to emulate for dom0 too. Then it will be easy to hide
a capability whose initialization fails in a function.

Signed-off-by: Jiqian Chen <Jiqian.Chen@xxxxxxx>
---
cc: "Roger Pau Monné" <roger.pau@xxxxxxxxxx>
---
v2->v3 changes:
* Not to add handler of PCI_CAP_LIST_ID when domain is dom0.

v1->v2 changes:
new patch.

Best regards,
Jiqian Chen.
---
 xen/drivers/vpci/header.c | 25 ++++++++++++++-----------
 1 file changed, 14 insertions(+), 11 deletions(-)

diff --git a/xen/drivers/vpci/header.c b/xen/drivers/vpci/header.c
index 3e9b44454b43..c98cd211d9d7 100644
--- a/xen/drivers/vpci/header.c
+++ b/xen/drivers/vpci/header.c
@@ -749,9 +749,9 @@ static int vpci_init_capability_list(struct pci_dev *pdev)
 {
     int rc;
     bool mask_cap_list = false;
+    bool is_hwdom = is_hardware_domain(pdev->domain);
 
-    if ( !is_hardware_domain(pdev->domain) &&
-         pci_conf_read16(pdev->sbdf, PCI_STATUS) & PCI_STATUS_CAP_LIST )
+    if ( pci_conf_read16(pdev->sbdf, PCI_STATUS) & PCI_STATUS_CAP_LIST )
     {
         /* Only expose capabilities to the guest that vPCI can handle. */
         unsigned int next, ttl = 48;
@@ -759,10 +759,11 @@ static int vpci_init_capability_list(struct pci_dev *pdev)
             PCI_CAP_ID_MSI,
             PCI_CAP_ID_MSIX,
         };
+        const unsigned int *caps = is_hwdom ? NULL : supported_caps;
+        const unsigned int n = is_hwdom ? 0 : ARRAY_SIZE(supported_caps);
 
         next = pci_find_next_cap_ttl(pdev->sbdf, PCI_CAPABILITY_LIST,
-                                     supported_caps,
-                                     ARRAY_SIZE(supported_caps), &ttl);
+                                     caps, n, &ttl);
 
         rc = vpci_add_register(pdev->vpci, vpci_read_val, NULL,
                                PCI_CAPABILITY_LIST, 1,
@@ -772,7 +773,7 @@ static int vpci_init_capability_list(struct pci_dev *pdev)
 
         next &= ~3;
 
-        if ( !next )
+        if ( !next && !is_hwdom )
             /*
              * If we don't have any supported capabilities to expose to the
              * guest, mask the PCI_STATUS_CAP_LIST bit in the status
@@ -786,13 +787,15 @@ static int vpci_init_capability_list(struct pci_dev *pdev)
 
             next = pci_find_next_cap_ttl(pdev->sbdf,
                                          pos + PCI_CAP_LIST_NEXT,
-                                         supported_caps,
-                                         ARRAY_SIZE(supported_caps), &ttl);
+                                         caps, n, &ttl);
 
-            rc = vpci_add_register(pdev->vpci, vpci_hw_read8, NULL,
-                                   pos + PCI_CAP_LIST_ID, 1, NULL);
-            if ( rc )
-                return rc;
+            if ( !is_hwdom )
+            {
+                rc = vpci_add_register(pdev->vpci, vpci_hw_read8, NULL,
+                                       pos + PCI_CAP_LIST_ID, 1, NULL);
+                if ( rc )
+                    return rc;
+            }
 
             rc = vpci_add_register(pdev->vpci, vpci_read_val, NULL,
                                    pos + PCI_CAP_LIST_NEXT, 1,
-- 
2.34.1