[PATCH v9 8/8] vpci/msix: Free MSIX resources when init_msix() fails

[Jiqian Chen <Jiqian.Chen@xxxxxxx>]

When MSI-X initialization fails vPCI will hide the capability, but
remove of handlers and data won't be performed until the device is
deassigned.  Introduce a MSI-X cleanup hook that will be called when
initialization fails to cleanup MSI-X related hooks and free it's
associated data.

As all supported capabilities have been switched to use the cleanup
hooks call those from vpci_deassign_device() instead of open-code the
capability specific cleanup in there.

Signed-off-by: Jiqian Chen <Jiqian.Chen@xxxxxxx>
---
cc: "Roger Pau Monné" <roger.pau@xxxxxxxxxx>
---
v8->v9 changes:
* Modify commit message.
* Call cleanup_msix() in vpci_deassign_device() to remove the open-code to 
cleanup msix datas.
* In cleanup_msix(), move "list_del(&vpci->msix->next);" above for loop of 
iounmap msix tables.

v7->v8 changes:
* Given the code in vpci_remove_registers() an error in the removal of
  registers would likely imply memory corruption, at which point it's
  best to fully disable the device. So, Rollback the last two modifications of 
v7.

v6->v7 changes:
* Change the pointer parameter of cleanup_msix() to be const.
* When vpci_remove_registers() in cleanup_msix() fails, not to return
  directly, instead try to free msix and re-add ctrl handler.
* Pass pdev->vpci into vpci_add_register() instead of pdev->vpci->msix in
  init_msix() since we need that every handler realize that msix is NULL
  when msix is freed but handlers are still in there.

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 | 44 ++++++++++++++++++++++++++++++++++++++++-
 xen/drivers/vpci/vpci.c | 16 +++++++--------
 xen/include/xen/vpci.h  |  2 ++
 3 files changed, 53 insertions(+), 9 deletions(-)

diff --git a/xen/drivers/vpci/msix.c b/xen/drivers/vpci/msix.c
index 54a5070733aa..8ee315eb928c 100644
--- a/xen/drivers/vpci/msix.c
+++ b/xen/drivers/vpci/msix.c
@@ -655,6 +655,48 @@ int vpci_make_msix_hole(const struct pci_dev *pdev)
     return 0;
 }
 
+int cleanup_msix(const 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 )
+    {
+        printk(XENLOG_ERR "%pd %pp: fail to remove MSIX handlers rc=%d\n",
+               pdev->domain, &pdev->sbdf, rc);
+        ASSERT_UNREACHABLE();
+        return rc;
+    }
+
+    if ( vpci->msix )
+    {
+        list_del(&vpci->msix->next);
+        for ( unsigned int i = 0; i < ARRAY_SIZE(vpci->msix->table); i++ )
+            if ( vpci->msix->table[i] )
+                iounmap(vpci->msix->table[i]);
+
+        XFREE(vpci->msix);
+    }
+
+    /*
+     * The driver may not traverse the capability list and think device
+     * supports MSIX by default. So here let the control register of MSIX
+     * be Read-Only is to ensure MSIX disabled.
+     */
+    rc = vpci_add_register(vpci, vpci_hw_read16, NULL,
+                           msix_control_reg(msix_pos), 2, NULL);
+    if ( rc )
+        printk(XENLOG_ERR "%pd %pp: fail to add MSIX ctrl handler rc=%d\n",
+               pdev->domain, &pdev->sbdf, rc);
+
+    return rc;
+}
+
 static int cf_check init_msix(struct pci_dev *pdev)
 {
     struct domain *d = pdev->domain;
@@ -710,7 +752,7 @@ static int cf_check init_msix(struct pci_dev *pdev)
      */
     return vpci_make_msix_hole(pdev);
 }
-REGISTER_VPCI_CAP(MSIX, init_msix, NULL);
+REGISTER_VPCI_CAP(MSIX, init_msix, cleanup_msix);
 
 /*
  * Local variables:
diff --git a/xen/drivers/vpci/vpci.c b/xen/drivers/vpci/vpci.c
index 4b8e6b28bd07..258356019535 100644
--- a/xen/drivers/vpci/vpci.c
+++ b/xen/drivers/vpci/vpci.c
@@ -321,6 +321,14 @@ void vpci_deassign_device(struct pci_dev *pdev)
                     &pdev->domain->vpci_dev_assigned_map);
 #endif
 
+    if ( pdev->vpci->msix )
+    {
+        int rc = cleanup_msix(pdev);
+        if ( rc )
+            printk(XENLOG_ERR "%pd %pp: fail to cleanup MSIX datas rc=%d\n",
+                   pdev->domain, &pdev->sbdf, rc);
+    }
+
     spin_lock(&pdev->vpci->lock);
     while ( !list_empty(&pdev->vpci->handlers) )
     {
@@ -332,18 +340,10 @@ void vpci_deassign_device(struct pci_dev *pdev)
         xfree(r);
     }
     spin_unlock(&pdev->vpci->lock);
-    if ( pdev->vpci->msix )
-    {
-        list_del(&pdev->vpci->msix->next);
-        for ( i = 0; i < ARRAY_SIZE(pdev->vpci->msix->table); i++ )
-            if ( pdev->vpci->msix->table[i] )
-                iounmap(pdev->vpci->msix->table[i]);
-    }
 
     for ( i = 0; i < ARRAY_SIZE(pdev->vpci->header.bars); i++ )
         rangeset_destroy(pdev->vpci->header.bars[i].mem);
 
-    xfree(pdev->vpci->msix);
     xfree(pdev->vpci->msi);
     xfree(pdev->vpci);
     pdev->vpci = NULL;
diff --git a/xen/include/xen/vpci.h b/xen/include/xen/vpci.h
index 514a0ce39133..6f9c7b6fb38f 100644
--- a/xen/include/xen/vpci.h
+++ b/xen/include/xen/vpci.h
@@ -220,6 +220,8 @@ void vpci_dump_msi(void);
 /* Make sure there's a hole in the p2m for the MSIX mmio areas. */
 int vpci_make_msix_hole(const struct pci_dev *pdev);
 
+int __must_check cleanup_msix(const struct pci_dev *pdev);
+
 /* Arch-specific vPCI MSI helpers. */
 void vpci_msi_arch_mask(struct vpci_msi *msi, const struct pci_dev *pdev,
                         unsigned int entry, bool mask);
-- 
2.34.1