x86/ucode: Distinguish "ucode already up to date"

Right now, Xen returns -ENOENT for both "the provided blob isn't correct for
this CPU", and "the blob isn't newer than what's loaded".

This in turn causes xen-ucode to exit with an error, when "nothing to do" is
more commonly a success condition.

Handle EEXIST specially and exit cleanly.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>
master commit: 648db37a155aca6f66d4cf3bb118417a728c3579
master date: 2024-05-09 18:19:49 +0100

diff --git a/tools/misc/xen-ucode.c b/tools/misc/xen-ucode.c
index c6ae6498d6599dd188b25d71108efac4671b0887..390969db3d1cc06fb32c356c9df5e0cc27e07de3 100644 (file)
--- a/tools/misc/xen-ucode.c
+++ b/tools/misc/xen-ucode.c
@@ -125,8 +125,11 @@ int main(int argc, char *argv[])
         exit(1);
     }
 
+    errno = 0;
     ret = xc_microcode_update(xch, buf, len);
-    if ( ret )
+    if ( ret == -1 && errno == EEXIST )
+        printf("Microcode already up to date\n");
+    else if ( ret )
     {
         fprintf(stderr, "Failed to update microcode. (err: %s)\n",
                 strerror(errno));

diff --git a/xen/arch/x86/cpu/microcode/core.c b/xen/arch/x86/cpu/microcode/core.c
index 4e011cdc413f78620b08e4c55c191e1352b30afe..d5338ad345fdce4e67f95c7cc89653ee01eabaf1 100644 (file)
--- a/xen/arch/x86/cpu/microcode/core.c
+++ b/xen/arch/x86/cpu/microcode/core.c
@@ -640,7 +640,7 @@ static long cf_check microcode_update_helper(void *data)
                    "microcode: couldn't find any newer%s revision in the provided blob!\n",
                    opt_ucode_allow_same ? " (or the same)" : "");
             microcode_free_patch(patch);
-            ret = -ENOENT;
+            ret = -EEXIST;
 
             goto put;
         }