[Xen-devel] [PATCH v11 2/7] microcode: unify ucode loading during system bootup and resuming

[Chao Gao <chao.gao@xxxxxxxxx>]

During system bootup and resuming, CPUs just load the cached ucode.
So one unified function microcode_update_one() is introduced. It
takes a boolean to indicate whether ->start_update should be called.
Since early_microcode_update_cpu() is only called on BSP (APs call
the unified function), start_update is always true and so remove
this parameter.

There is a functional change: ->start_update is called on BSP and
->end_update_percpu is called during system resuming. They are not
invoked by previous microcode_resume_cpu().

Signed-off-by: Chao Gao <chao.gao@xxxxxxxxx>
Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
---
Changes in v10:
 - call ->start_update for system resume from suspension

Changes in v9:
 - return -EOPNOTSUPP rather than 0 if microcode_ops is NULL in
   microcode_update_one()
 - rebase and fix conflicts.

Changes in v8:
 - split out from the previous patch
---
 xen/arch/x86/acpi/power.c       |  2 +-
 xen/arch/x86/microcode.c        | 91 +++++++++++++++++++----------------------
 xen/arch/x86/smpboot.c          |  5 +--
 xen/include/asm-x86/processor.h |  4 +-
 4 files changed, 45 insertions(+), 57 deletions(-)

diff --git a/xen/arch/x86/acpi/power.c b/xen/arch/x86/acpi/power.c
index 269b140..01e6aec 100644
--- a/xen/arch/x86/acpi/power.c
+++ b/xen/arch/x86/acpi/power.c
@@ -278,7 +278,7 @@ static int enter_state(u32 state)
 
     console_end_sync();
 
-    microcode_resume_cpu();
+    microcode_update_one(true);
 
     if ( !recheck_cpu_features(0) )
         panic("Missing previously available feature(s)\n");
diff --git a/xen/arch/x86/microcode.c b/xen/arch/x86/microcode.c
index 3ea2a6e..9c0e5c4 100644
--- a/xen/arch/x86/microcode.c
+++ b/xen/arch/x86/microcode.c
@@ -203,24 +203,6 @@ static struct microcode_patch *parse_blob(const char *buf, 
size_t len)
     return NULL;
 }
 
-int microcode_resume_cpu(void)
-{
-    int err;
-    struct cpu_signature *sig = &this_cpu(cpu_sig);
-
-    if ( !microcode_ops )
-        return 0;
-
-    spin_lock(&microcode_mutex);
-
-    err = microcode_ops->collect_cpu_info(sig);
-    if ( likely(!err) )
-        err = microcode_ops->apply_microcode(microcode_cache);
-    spin_unlock(&microcode_mutex);
-
-    return err;
-}
-
 void microcode_free_patch(struct microcode_patch *microcode_patch)
 {
     microcode_ops->free_patch(microcode_patch->mc);
@@ -391,11 +373,38 @@ static int __init microcode_init(void)
 }
 __initcall(microcode_init);
 
-int __init early_microcode_update_cpu(bool start_update)
+/* Load a cached update to current cpu */
+int microcode_update_one(bool start_update)
+{
+    int err;
+
+    if ( !microcode_ops )
+        return -EOPNOTSUPP;
+
+    microcode_ops->collect_cpu_info(&this_cpu(cpu_sig));
+
+    if ( start_update && microcode_ops->start_update )
+    {
+        err = microcode_ops->start_update();
+        if ( err )
+            return err;
+    }
+
+    err = microcode_update_cpu(NULL);
+
+    if ( microcode_ops->end_update_percpu )
+        microcode_ops->end_update_percpu();
+
+    return err;
+}
+
+/* BSP calls this function to parse ucode blob and then apply an update. */
+int __init early_microcode_update_cpu(void)
 {
     int rc = 0;
     void *data = NULL;
     size_t len;
+    struct microcode_patch *patch;
 
     if ( !microcode_ops )
         return -ENOSYS;
@@ -411,44 +420,26 @@ int __init early_microcode_update_cpu(bool start_update)
         data = bootstrap_map(&ucode_mod);
     }
 
-    microcode_ops->collect_cpu_info(&this_cpu(cpu_sig));
-
     if ( !data )
         return -ENOMEM;
 
-    if ( start_update )
+    patch = parse_blob(data, len);
+    if ( IS_ERR(patch) )
     {
-        struct microcode_patch *patch;
-
-        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);
-
-        if ( microcode_ops->start_update )
-            rc = microcode_ops->start_update();
-
-        if ( rc )
-            return rc;
+        printk(XENLOG_WARNING "Parsing microcode blob error %ld\n",
+               PTR_ERR(patch));
+        return PTR_ERR(patch);
     }
 
-    rc = microcode_update_cpu(NULL);
+    if ( !patch )
+        return -ENOENT;
 
-    if ( microcode_ops->end_update_percpu )
-        microcode_ops->end_update_percpu();
+    spin_lock(&microcode_mutex);
+    rc = microcode_update_cache(patch);
+    spin_unlock(&microcode_mutex);
+    ASSERT(rc);
 
-    return rc;
+    return microcode_update_one(true);
 }
 
 int __init early_microcode_init(void)
@@ -468,7 +459,7 @@ int __init early_microcode_init(void)
         microcode_ops->collect_cpu_info(&this_cpu(cpu_sig));
 
         if ( ucode_mod.mod_end || ucode_blob.size )
-            rc = early_microcode_update_cpu(true);
+            rc = early_microcode_update_cpu();
     }
 
     return rc;
diff --git a/xen/arch/x86/smpboot.c b/xen/arch/x86/smpboot.c
index 73a1afc..179f6b6 100644
--- a/xen/arch/x86/smpboot.c
+++ b/xen/arch/x86/smpboot.c
@@ -360,10 +360,7 @@ void start_secondary(void *unused)
 
     initialize_cpu_data(cpu);
 
-    if ( system_state <= SYS_STATE_smp_boot )
-        early_microcode_update_cpu(false);
-    else
-        microcode_resume_cpu();
+    microcode_update_one(false);
 
     /*
      * If MSR_SPEC_CTRL is available, apply Xen's default setting and discard
diff --git a/xen/include/asm-x86/processor.h b/xen/include/asm-x86/processor.h
index a673372..c92956f 100644
--- a/xen/include/asm-x86/processor.h
+++ b/xen/include/asm-x86/processor.h
@@ -569,9 +569,9 @@ int guest_wrmsr_xen(struct vcpu *v, uint32_t idx, uint64_t 
val);
 
 void microcode_set_module(unsigned int);
 int microcode_update(XEN_GUEST_HANDLE_PARAM(const_void), unsigned long len);
-int microcode_resume_cpu(void);
-int early_microcode_update_cpu(bool start_update);
+int early_microcode_update_cpu(void);
 int early_microcode_init(void);
+int microcode_update_one(bool start_update);
 int microcode_init_intel(void);
 int microcode_init_amd(void);
 
-- 
1.8.3.1


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