[PATCH v6 8/8] vpci/msix: Free MSIX resources when init_msix() fails

[Jiqian Chen <Jiqian.Chen@xxxxxxx>]

When init_msix() fails, current logic return fail and free MSIX-related
resources in vpci_deassign_device(). But the previous new changes will
hide MSIX capability and return success, it can't reach
vpci_deassign_device() to remove resources if hiding success, so those
resources must be removed in cleanup function of MSIX.

To do that, implement cleanup function for MSIX.

Signed-off-by: Jiqian Chen <Jiqian.Chen@xxxxxxx>
---
cc: "Roger Pau Monné" <roger.pau@xxxxxxxxxx>
---
v5->v6 changes:
* Change the logic to add dummy handler when !vpci->msix in cleanup_msix().

v4->v5 changes:
* Change definition "static void cleanup_msix" to "static int cf_check 
cleanup_msix" since cleanup hook is changed to be int.
* Add a read-only register for MSIX Control Register in the end of 
cleanup_msix().

v3->v4 changes:
* Change function name from fini_msix() to cleanup_msix().
* Change to use XFREE to free vpci->msix.
* In cleanup function, change the sequence of check and remove action according 
to init_msix().

v2->v3 changes:
* Remove unnecessary clean operations in fini_msix().

v1->v2 changes:
new patch.

Best regards,
Jiqian Chen.
---
 xen/drivers/vpci/msix.c | 29 ++++++++++++++++++++++++++++-
 1 file changed, 28 insertions(+), 1 deletion(-)

diff --git a/xen/drivers/vpci/msix.c b/xen/drivers/vpci/msix.c
index 674815ead025..da293e7494fd 100644
--- a/xen/drivers/vpci/msix.c
+++ b/xen/drivers/vpci/msix.c
@@ -655,6 +655,33 @@ int vpci_make_msix_hole(const struct pci_dev *pdev)
     return 0;
 }
 
+static int cf_check cleanup_msix(struct pci_dev *pdev)
+{
+    int rc;
+    struct vpci *vpci = pdev->vpci;
+    const unsigned int msix_pos = pdev->msix_pos;
+
+    if ( !msix_pos )
+        return 0;
+
+    rc = vpci_remove_registers(vpci, msix_control_reg(msix_pos), 2);
+    if ( rc )
+        return rc;
+
+    if ( vpci->msix )
+    {
+        for ( unsigned int i = 0; i < ARRAY_SIZE(vpci->msix->table); i++ )
+            if ( vpci->msix->table[i] )
+                iounmap(vpci->msix->table[i]);
+
+        list_del(&vpci->msix->next);
+        XFREE(vpci->msix);
+    }
+
+    return vpci_add_register(pdev->vpci, vpci_hw_read16, NULL,
+                             msix_control_reg(msix_pos), 2, NULL);
+}
+
 static int cf_check init_msix(struct pci_dev *pdev)
 {
     struct domain *d = pdev->domain;
@@ -709,7 +736,7 @@ static int cf_check init_msix(struct pci_dev *pdev)
 
     return rc;
 }
-REGISTER_VPCI_CAP(PCI_CAP_ID_MSIX, init_msix, NULL);
+REGISTER_VPCI_CAP(PCI_CAP_ID_MSIX, init_msix, cleanup_msix);
 
 /*
  * Local variables:
-- 
2.34.1