[PATCH v1 2/3] vpci/rebar: Remove registers when init_rebar() fails

[Jiqian Chen <Jiqian.Chen@xxxxxxx>]

When init_rebar() fails, the new codes will try to hide Rebar
capability, so it can't rely on vpci_deassign_device() to remove
all Rebar related registers anymore, those registers must be
cleaned up in failure path of init_rebar.

To do that, use a vpci_register array to record all Rebar registers
and call vpci_remove_register() to remove registers.

Signed-off-by: Jiqian Chen <Jiqian.Chen@xxxxxxx>
---
 xen/drivers/vpci/rebar.c | 33 ++++++++++++++++++++-------------
 xen/drivers/vpci/vpci.c  | 14 --------------
 xen/include/xen/vpci.h   | 15 +++++++++++++++
 3 files changed, 35 insertions(+), 27 deletions(-)

diff --git a/xen/drivers/vpci/rebar.c b/xen/drivers/vpci/rebar.c
index 7c53ee031887..5f2f9978feb9 100644
--- a/xen/drivers/vpci/rebar.c
+++ b/xen/drivers/vpci/rebar.c
@@ -51,8 +51,11 @@ static void cf_check rebar_ctrl_write(const struct pci_dev 
*pdev,
 
 static int cf_check init_rebar(struct pci_dev *pdev)
 {
+    int rc = 0;
     uint32_t ctrl;
     unsigned int nbars;
+    unsigned int reg_index = 0;
+    struct vpci_register registers[VPCI_CAP_MAX_REGISTER];
     unsigned int rebar_offset = pci_find_ext_capability(pdev->sbdf,
                                                         PCI_EXT_CAP_ID_REBAR);
 
@@ -70,17 +73,17 @@ static int cf_check init_rebar(struct pci_dev *pdev)
     nbars = MASK_EXTR(ctrl, PCI_REBAR_CTRL_NBAR_MASK);
     for ( unsigned int i = 0; i < nbars; i++ )
     {
-        int rc;
+        const unsigned int offset = rebar_offset + PCI_REBAR_CTRL(i);
         struct vpci_bar *bar;
         unsigned int index;
 
-        ctrl = pci_conf_read32(pdev->sbdf, rebar_offset + PCI_REBAR_CTRL(i));
+        ctrl = pci_conf_read32(pdev->sbdf, offset);
         index = ctrl & PCI_REBAR_CTRL_BAR_IDX;
         if ( index >= PCI_HEADER_NORMAL_NR_BARS )
         {
             printk(XENLOG_ERR "%pd %pp: too big BAR number %u in REBAR_CTRL\n",
                    pdev->domain, &pdev->sbdf, index);
-            continue;
+            goto fail;
         }
 
         bar = &pdev->vpci->header.bars[index];
@@ -88,24 +91,19 @@ static int cf_check init_rebar(struct pci_dev *pdev)
         {
             printk(XENLOG_ERR "%pd %pp: BAR%u is not in memory space\n",
                    pdev->domain, &pdev->sbdf, index);
-            continue;
+            goto fail;
         }
 
         rc = vpci_add_register(pdev->vpci, vpci_hw_read32, rebar_ctrl_write,
-                               rebar_offset + PCI_REBAR_CTRL(i), 4, bar);
+                               offset, 4, bar);
         if ( rc )
         {
             printk(XENLOG_ERR "%pd %pp: BAR%u fail to add reg of REBAR_CTRL 
rc=%d\n",
                    pdev->domain, &pdev->sbdf, index, rc);
-            /*
-             * Ideally we would hide the ReBar capability on error, but code
-             * for doing so still needs to be written. Use continue instead
-             * to keep any already setup register hooks, as returning an
-             * error will cause the hardware domain to get unmediated access
-             * to all device registers.
-             */
-            continue;
+            goto fail;
         }
+        registers[reg_index].offset = offset;
+        registers[reg_index++].size = 4;
 
         bar->resizable_sizes =
             MASK_EXTR(pci_conf_read32(pdev->sbdf,
@@ -117,6 +115,15 @@ static int cf_check init_rebar(struct pci_dev *pdev)
     }
 
     return 0;
+
+ fail:
+    for ( unsigned int i = 0; i < reg_index; i++ )
+        if ( vpci_remove_register(pdev->vpci,
+                                  registers[i].offset,
+                                  registers[i].size) )
+            continue;
+
+    return rc;
 }
 REGISTER_VPCI_EXTEND_CAP(PCI_EXT_CAP_ID_REBAR, init_rebar, VPCI_PRIORITY_LOW);
 
diff --git a/xen/drivers/vpci/vpci.c b/xen/drivers/vpci/vpci.c
index a8362e46e097..ea81d8cc9604 100644
--- a/xen/drivers/vpci/vpci.c
+++ b/xen/drivers/vpci/vpci.c
@@ -21,20 +21,6 @@
 #include <xen/vpci.h>
 #include <xen/vmap.h>
 
-/* Internal struct to store the emulated PCI registers. */
-struct vpci_register {
-    vpci_read_t *read;
-    vpci_write_t *write;
-    unsigned int size;
-    unsigned int offset;
-    void *private;
-    struct list_head node;
-    uint32_t ro_mask;
-    uint32_t rw1c_mask;
-    uint32_t rsvdp_mask;
-    uint32_t rsvdz_mask;
-};
-
 #ifdef __XEN__
 extern vpci_capability_t *const __start_vpci_array[];
 extern vpci_capability_t *const __end_vpci_array[];
diff --git a/xen/include/xen/vpci.h b/xen/include/xen/vpci.h
index fa13397ae409..19a036c22165 100644
--- a/xen/include/xen/vpci.h
+++ b/xen/include/xen/vpci.h
@@ -214,6 +214,21 @@ struct vpci_vcpu {
     bool rom_only : 1;
 };
 
+#define VPCI_CAP_MAX_REGISTER 10
+
+struct vpci_register {
+    vpci_read_t *read;
+    vpci_write_t *write;
+    unsigned int size;
+    unsigned int offset;
+    void *private;
+    struct list_head node;
+    uint32_t ro_mask;
+    uint32_t rw1c_mask;
+    uint32_t rsvdp_mask;
+    uint32_t rsvdz_mask;
+};
+
 #ifdef __XEN__
 void vpci_dump_msi(void);
 
-- 
2.34.1