[PATCH 2/5] x86/ucode: Fold early_update_cache() into microcode_init_cache()

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

It is not valid to retain a bootstrap_map() across returning back to
__start_xen(), but various pointers get stashed across calls.

Begin to address this by folding early_update_cache() into it's single caller,
rearranging the exit path to always invalidate the mapping.

No practical change.

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
CC: Jan Beulich <JBeulich@xxxxxxxx>
CC: Roger Pau Monné <roger.pau@xxxxxxxxxx>
CC: Wei Liu <wl@xxxxxxx>
CC: Sergey Dyasli <sergey.dyasli@xxxxxxxxxx>
---
 xen/arch/x86/cpu/microcode/core.c | 54 +++++++++++++++++--------------
 1 file changed, 29 insertions(+), 25 deletions(-)

diff --git a/xen/arch/x86/cpu/microcode/core.c 
b/xen/arch/x86/cpu/microcode/core.c
index 11c471cc3f83..3d23e3ed7ee4 100644
--- a/xen/arch/x86/cpu/microcode/core.c
+++ b/xen/arch/x86/cpu/microcode/core.c
@@ -755,47 +755,51 @@ int microcode_update_one(void)
     return microcode_update_cpu(NULL);
 }
 
-static int __init early_update_cache(const void *data, size_t len)
+int __init microcode_init_cache(unsigned long *module_map,
+                                const struct multiboot_info *mbi)
 {
     int rc = 0;
     struct microcode_patch *patch;
+    struct ucode_mod_blob blob = {};
 
-    if ( !data )
-        return -ENOMEM;
+    if ( ucode_scan )
+        /* Need to rescan the modules because they might have been relocated */
+        microcode_scan_module(module_map, mbi);
+
+    if ( ucode_mod.mod_end )
+    {
+        blob.data = bootstrap_map(&ucode_mod);
+        blob.size = ucode_mod.mod_end;
+    }
+    else if ( ucode_blob.size )
+    {
+        blob = ucode_blob;
+    }
 
-    patch = parse_blob(data, len);
+    if ( !blob.data )
+        return 0;
+
+    patch = parse_blob(blob.data, blob.size);
     if ( IS_ERR(patch) )
     {
-        printk(XENLOG_WARNING "Parsing microcode blob error %ld\n",
-               PTR_ERR(patch));
-        return PTR_ERR(patch);
+        rc = PTR_ERR(patch);
+        printk(XENLOG_WARNING "Parsing microcode blob error %d\n", rc);
+        goto out;
     }
 
     if ( !patch )
-        return -ENOENT;
+    {
+        rc = -ENOENT;
+        goto out;
+    }
 
     spin_lock(&microcode_mutex);
     rc = microcode_update_cache(patch);
     spin_unlock(&microcode_mutex);
     ASSERT(rc);
 
-    return rc;
-}
-
-int __init microcode_init_cache(unsigned long *module_map,
-                                const struct multiboot_info *mbi)
-{
-    int rc = 0;
-
-    if ( ucode_scan )
-        /* Need to rescan the modules because they might have been relocated */
-        microcode_scan_module(module_map, mbi);
-
-    if ( ucode_mod.mod_end )
-        rc = early_update_cache(bootstrap_map(&ucode_mod),
-                                ucode_mod.mod_end);
-    else if ( ucode_blob.size )
-        rc = early_update_cache(ucode_blob.data, ucode_blob.size);
+ out:
+    bootstrap_map(NULL);
 
     return rc;
 }
-- 
2.30.2