@@ -263,40 +263,6 @@ static bool cf_check wait_cpu_callout(unsigned int nr)
return atomic_read(&cpu_out) >= nr;
}
-/*
- * Load a microcode update to current CPU.
- *
- * If no patch is provided, the cached patch will be loaded. Microcode update
- * during APs bringup and CPU resuming falls into this case.
- */
-static int microcode_update_cpu(const struct microcode_patch *patch,
- unsigned int flags)
-{
- int err;
-
- alternative_vcall(ucode_ops.collect_cpu_info);
-
- spin_lock(µcode_mutex);
- if ( patch )
- err = alternative_call(ucode_ops.apply_microcode, patch, flags);
- else if ( microcode_cache )
- {
- err = alternative_call(ucode_ops.apply_microcode, microcode_cache,
- flags);
- if ( err == -EIO )
- {
- microcode_free_patch(microcode_cache);
- microcode_cache = NULL;
- }
- }
- else
- /* No patch to update */
- err = -ENOENT;
- spin_unlock(µcode_mutex);
-
- return err;
-}
-
static bool wait_for_state(typeof(loading_state) state)
{
typeof(loading_state) cur_state;
@@ -702,13 +668,26 @@ int microcode_update(XEN_GUEST_HANDLE(const_void) buf,
/* Load a cached update to current cpu */
int microcode_update_one(void)
{
+ int rc;
+
+ /*
+ * This path is used for APs and S3 resume. Read the microcode revision
+ * if possible, even if we can't load microcode.
+ */
if ( ucode_ops.collect_cpu_info )
alternative_vcall(ucode_ops.collect_cpu_info);
if ( !ucode_ops.apply_microcode )
return -EOPNOTSUPP;
- return microcode_update_cpu(NULL, 0);
+ spin_lock(µcode_mutex);
+ if ( microcode_cache )
+ rc = alternative_call(ucode_ops.apply_microcode, microcode_cache, 0);
+ else
+ rc = -ENOENT;
+ spin_unlock(µcode_mutex);
+
+ return rc;
}
/*
Fold microcode_update_cpu() into its single remaining caller and simplify the logic by removing the patch != NULL path with microcode_mutex held. Explain why we bother grabbing the microcode revision even if we can't load microcode. Furthermore, delete the -EIO path. An error updating microcode on AP boot or S3 resume is certainly bad, but freeing the cache is about the worst possible action we can take in response; it prevents subsequent APs from taking an update they might have accepted. This avoids a double collect_cpu_info() call on each AP. Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> --- CC: Jan Beulich <JBeulich@suse.com> CC: Roger Pau Monné <roger.pau@citrix.com> --- xen/arch/x86/cpu/microcode/core.c | 49 +++++++++---------------------- 1 file changed, 14 insertions(+), 35 deletions(-)