[PATCH 3/5] x86/ucode: Fold early_microcode_update_cpu() into early_microcode_init()

[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 | 70 +++++++++++++++----------------
 1 file changed, 33 insertions(+), 37 deletions(-)

diff --git a/xen/arch/x86/cpu/microcode/core.c 
b/xen/arch/x86/cpu/microcode/core.c
index 3d23e3ed7ee4..4d2a896fe78d 100644
--- a/xen/arch/x86/cpu/microcode/core.c
+++ b/xen/arch/x86/cpu/microcode/core.c
@@ -804,45 +804,12 @@ int __init microcode_init_cache(unsigned long *module_map,
     return rc;
 }
 
-/* BSP calls this function to parse ucode blob and then apply an update. */
-static int __init early_microcode_update_cpu(void)
-{
-    const void *data = NULL;
-    size_t len;
-    struct microcode_patch *patch;
-
-    if ( ucode_blob.size )
-    {
-        len = ucode_blob.size;
-        data = ucode_blob.data;
-    }
-    else if ( ucode_mod.mod_end )
-    {
-        len = ucode_mod.mod_end;
-        data = bootstrap_map(&ucode_mod);
-    }
-
-    if ( !data )
-        return -ENOMEM;
-
-    patch = ucode_ops.cpu_request_microcode(data, len, false);
-    if ( IS_ERR(patch) )
-    {
-        printk(XENLOG_WARNING "Parsing microcode blob error %ld\n",
-               PTR_ERR(patch));
-        return PTR_ERR(patch);
-    }
-
-    if ( !patch )
-        return -ENOENT;
-
-    return microcode_update_cpu(patch);
-}
-
 int __init early_microcode_init(unsigned long *module_map,
                                 const struct multiboot_info *mbi)
 {
     const struct cpuinfo_x86 *c = &boot_cpu_data;
+    struct microcode_patch *patch;
+    struct ucode_mod_blob blob = {};
     int rc = 0;
 
     switch ( c->x86_vendor )
@@ -868,8 +835,37 @@ int __init early_microcode_init(unsigned long *module_map,
 
     ucode_ops.collect_cpu_info();
 
-    if ( ucode_mod.mod_end || ucode_blob.size )
-        rc = early_microcode_update_cpu();
+    if ( ucode_blob.data )
+    {
+        blob = ucode_blob;
+    }
+    else if ( ucode_mod.mod_end )
+    {
+        blob.data = bootstrap_map(&ucode_mod);
+        blob.size = ucode_mod.mod_end;
+    }
+
+    if ( !blob.data )
+        return 0;
+
+    patch = ucode_ops.cpu_request_microcode(blob.data, blob.size, false);
+    if ( IS_ERR(patch) )
+    {
+        rc = PTR_ERR(patch);
+        printk(XENLOG_WARNING "Parsing microcode blob error %d\n", rc);
+        goto out;
+    }
+
+    if ( !patch )
+    {
+        rc = -ENOENT;
+        goto out;
+    }
+
+    rc = microcode_update_cpu(patch);
+
+ out:
+    bootstrap_map(NULL);
 
     return rc;
 }
-- 
2.30.2