[Xen-changelog] [xen master] x86/microcode: Check whether the microcode is correct

[patchbot@xxxxxxx]

commit 4deea8515b1caba8803816399068f2a75d65f8ad
Author:     Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
AuthorDate: Fri Sep 27 10:25:08 2013 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Fri Sep 27 10:25:08 2013 +0200

    x86/microcode: Check whether the microcode is correct
    
    We do the microcode code update in two steps - the presmp:
    'microcode_presmp_init' and when CPUs are brought up: 'microcode_init'.
    The earlier performs the microcode update on the BSP - but
    unfortunately it does not check whether the update failed. Which means
    that we might try later to update a incorrect payload on the rest of
    CPUs.
    
    This patch handles this odd situation.
    
    Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
    Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Acked-by: Keir Fraser <keir@xxxxxxx>
---
 xen/arch/x86/microcode.c |   17 ++++++++++++++++-
 1 files changed, 16 insertions(+), 1 deletions(-)

diff --git a/xen/arch/x86/microcode.c b/xen/arch/x86/microcode.c
index e6344cf..091d5d1 100644
--- a/xen/arch/x86/microcode.c
+++ b/xen/arch/x86/microcode.c
@@ -418,6 +418,7 @@ static int __init microcode_presmp_init(void)
         {
             void *data;
             size_t len;
+            int rc = 0;
 
             if ( ucode_blob.size )
             {
@@ -430,10 +431,24 @@ static int __init microcode_presmp_init(void)
                 data = ucode_mod_map(&ucode_mod);
             }
             if ( data )
-                microcode_update_cpu(data, len);
+                rc = microcode_update_cpu(data, len);
+            else
+                rc = -ENOMEM;
 
             if ( !ucode_blob.size )
                 ucode_mod_map(NULL);
+
+            if ( rc )
+            {
+                if ( ucode_blob.size )
+                {
+                    xfree(ucode_blob.data);
+                    ucode_blob.size = 0;
+                    ucode_blob.data = NULL;
+                }
+                else
+                    ucode_mod.mod_end = 0;
+            }
         }
 
         register_cpu_notifier(&microcode_percpu_nfb);
--
generated by git-patchbot for /home/xen/git/xen.git#master

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