diff mbox series

[v2,4/4] x86/ucode: Fold early_update_cache() into its single caller

Message ID 20241106003938.3453243-5-andrew.cooper3@citrix.com (mailing list archive)
State New
Headers show
Series x86/ucode: Fix module-handling use-after-free's | expand

Commit Message

Andrew Cooper Nov. 6, 2024, 12:39 a.m. UTC 
The data pointer is known good, so the -ENOMEM path is unnecessary.  However,
if we find no patch, something's wrong seeing as early_microcode_init()
indicated it was happy.

We are the entity initialising the cache, so we don't need the complexity of
using microcode_update_cache().  Just assert the cache is empty, and populate
it.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Daniel P. Smith <dpsmith@apertussolutions.com>
---
CC: Jan Beulich <JBeulich@suse.com>
CC: Roger Pau Monné <roger.pau@citrix.com>
CC: Daniel P. Smith <dpsmith@apertussolutions.com>
---
 xen/arch/x86/cpu/microcode/core.c | 47 +++++++++++++------------------
 1 file changed, 19 insertions(+), 28 deletions(-)
diff mbox series

Patch

diff --git a/xen/arch/x86/cpu/microcode/core.c b/xen/arch/x86/cpu/microcode/core.c
index 74b816a98b17..54ce1b5e2ba6 100644
--- a/xen/arch/x86/cpu/microcode/core.c
+++ b/xen/arch/x86/cpu/microcode/core.c
@@ -711,33 +711,6 @@  int microcode_update_one(void)
     return microcode_update_cpu(NULL, 0);
 }
 
-static int __init early_update_cache(const void *data, size_t len)
-{
-    int rc = 0;
-    struct microcode_patch *patch;
-
-    if ( !data )
-        return -ENOMEM;
-
-    patch = parse_blob(data, len);
-    if ( IS_ERR(patch) )
-    {
-        printk(XENLOG_WARNING "Parsing microcode blob error %ld\n",
-               PTR_ERR(patch));
-        return PTR_ERR(patch);
-    }
-
-    if ( !patch )
-        return -ENOENT;
-
-    spin_lock(&microcode_mutex);
-    rc = microcode_update_cache(patch);
-    spin_unlock(&microcode_mutex);
-    ASSERT(rc);
-
-    return rc;
-}
-
 /*
  * Set by early_microcode_load() to indicate where it found microcode, so
  * microcode_init_cache() can find it again and initalise the cache.  opt_scan
@@ -748,6 +721,7 @@  static int __initdata early_mod_idx = -1;
 static int __init cf_check microcode_init_cache(void)
 {
     struct boot_info *bi = &xen_boot_info;
+    struct microcode_patch *patch;
     void *data;
     size_t size;
     int rc = 0;
@@ -778,7 +752,24 @@  static int __init cf_check microcode_init_cache(void)
         size = cd.size;
     }
 
-    rc = early_update_cache(data, size);
+    patch = parse_blob(data, size);
+    if ( IS_ERR(patch) )
+    {
+        rc = PTR_ERR(patch);
+        printk(XENLOG_WARNING "Microcode: Parse error %d\n", rc);
+        return rc;
+    }
+
+    if ( !patch )
+    {
+        printk(XENLOG_WARNING "Microcode: No suitable patch found\n");
+        return -ENOENT;
+    }
+
+    spin_lock(&microcode_mutex);
+    ASSERT(microcode_cache == NULL);
+    microcode_cache = patch;
+    spin_unlock(&microcode_mutex);
 
     return rc;
 }