[xen staging] x86/ucode: Use bootstrap_unmap() in early_microcode_load()

[patchbot@xxxxxxx]

commit 414725d0eede077f03fe60a24019c133bc6ba037
Author:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
AuthorDate: Fri Oct 25 20:02:10 2024 +0100
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Wed Nov 6 18:59:41 2024 +0000

    x86/ucode: Use bootstrap_unmap() in early_microcode_load()
    
    If bootstrap_map() has provided a mapping, we must free it when done.  
Failing
    to do so may cause a spurious failure for unrelated logic later.
    
    Inserting a bootstrap_unmap() here does not break the use of 
ucode_{blob,mod}
    any more than they already are.
    
    Add a printk noting when we didn't find a microcode patch.  It's at debug
    level, because this is the expected case on AMD Client systems, and SDPs, 
but
    for people trying to figure out why microcode loading isn't work, it might 
be
    helpful.
    
    Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Acked-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-by: Daniel P. Smith <dpsmith@xxxxxxxxxxxxxxxxxxxx>
---
 xen/arch/x86/cpu/microcode/core.c | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/xen/arch/x86/cpu/microcode/core.c 
b/xen/arch/x86/cpu/microcode/core.c
index 97ed1f1158..a2b03c52e8 100644
--- a/xen/arch/x86/cpu/microcode/core.c
+++ b/xen/arch/x86/cpu/microcode/core.c
@@ -849,6 +849,7 @@ static int __init early_microcode_load(struct boot_info *bi)
     size_t size;
     struct microcode_patch *patch;
     int idx = opt_mod_idx;
+    int rc;
 
     /*
      * Cmdline parsing ensures this invariant holds, so that we don't end up
@@ -904,15 +905,24 @@ static int __init early_microcode_load(struct boot_info 
*bi)
     patch = ucode_ops.cpu_request_microcode(data, size, false);
     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 "Microcode: Parse error %d\n", rc);
+        goto unmap;
     }
 
     if ( !patch )
-        return -ENOENT;
+    {
+        printk(XENLOG_DEBUG "Microcode: No suitable patch found\n");
+        rc = -ENOENT;
+        goto unmap;
+    }
+
+    rc = microcode_update_cpu(patch, 0);
 
-    return microcode_update_cpu(patch, 0);
+ unmap:
+    bootstrap_unmap();
+
+    return rc;
 }
 
 int __init early_microcode_init(struct boot_info *bi)
--
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