[Xen-devel] [PATCH v4 4/6] microcode: don't call apply_microcode() in cpu_request_microcode()

[Chao Gao <chao.gao@xxxxxxxxx>]

cpu_request_microcode() will only parse microcode file and save
suitable microcodes to microcode_cache. To update microcode,
apply_microcode() should be invoked explicitly.

On AMD side, svm_host_osvw_init() is supposed to be called after
microcode update. As apply_micrcode() won't be called by
cpu_request_microcode() now, svm_host_osvw_init() is also moved to the
end of apply_microcode().

Signed-off-by: Chao Gao <chao.gao@xxxxxxxxx>
---
 xen/arch/x86/microcode.c       | 58 ++++++++++++++++++++++++++++++------------
 xen/arch/x86/microcode_amd.c   | 15 +++++------
 xen/arch/x86/microcode_intel.c |  5 +---
 3 files changed, 50 insertions(+), 28 deletions(-)

diff --git a/xen/arch/x86/microcode.c b/xen/arch/x86/microcode.c
index 8350d22..cca7b2c 100644
--- a/xen/arch/x86/microcode.c
+++ b/xen/arch/x86/microcode.c
@@ -233,20 +233,12 @@ int microcode_resume_cpu(unsigned int cpu)
     return err;
 }
 
-static int microcode_update_cpu(const void *buf, size_t size)
+static int microcode_update_cpu(void)
 {
     int err;
-    unsigned int cpu = smp_processor_id();
-    struct ucode_cpu_info *uci = &per_cpu(ucode_cpu_info, cpu);
 
     spin_lock(&microcode_mutex);
-
-    err = microcode_ops->collect_cpu_info(cpu, &uci->cpu_sig);
-    if ( likely(!err) )
-        err = microcode_ops->cpu_request_microcode(cpu, buf, size);
-    else
-        __microcode_fini_cpu(cpu);
-
+    err = microcode_ops->apply_microcode(smp_processor_id());
     spin_unlock(&microcode_mutex);
 
     return err;
@@ -259,7 +251,7 @@ static long do_microcode_update(void *_info)
 
     BUG_ON(info->cpu != smp_processor_id());
 
-    error = microcode_update_cpu(info->buffer, info->buffer_size);
+    error = microcode_update_cpu();
     if ( error )
         info->error = error;
 
@@ -276,6 +268,8 @@ int microcode_update(XEN_GUEST_HANDLE_PARAM(const_void) 
buf, unsigned long len)
 {
     int ret;
     struct microcode_info *info;
+    unsigned int cpu = smp_processor_id();
+    struct ucode_cpu_info *uci = &per_cpu(ucode_cpu_info, cpu);
 
     if ( len != (uint32_t)len )
         return -E2BIG;
@@ -294,10 +288,6 @@ int microcode_update(XEN_GUEST_HANDLE_PARAM(const_void) 
buf, unsigned long len)
         return ret;
     }
 
-    info->buffer_size = len;
-    info->error = 0;
-    info->cpu = cpumask_first(&cpu_online_map);
-
     if ( microcode_ops->start_update )
     {
         ret = microcode_ops->start_update();
@@ -308,6 +298,26 @@ int microcode_update(XEN_GUEST_HANDLE_PARAM(const_void) 
buf, unsigned long len)
         }
     }
 
+    spin_lock(&microcode_mutex);
+
+    ret = microcode_ops->collect_cpu_info(cpu, &uci->cpu_sig);
+    if ( likely(!ret) )
+        ret = microcode_ops->cpu_request_microcode(cpu, info->buffer, len);
+    else
+        __microcode_fini_cpu(cpu);
+
+    spin_unlock(&microcode_mutex);
+
+    if ( ret <= 0 )
+    {
+        printk("No valid or newer microcode found. Update abort!\n");
+        return -EINVAL;
+    }
+
+    info->buffer_size = len;
+    info->error = 0;
+    info->cpu = cpumask_first(&cpu_online_map);
+
     return continue_hypercall_on_cpu(info->cpu, do_microcode_update, info);
 }
 
@@ -370,13 +380,29 @@ int __init early_microcode_update_cpu(bool start_update)
     }
     if ( data )
     {
+        unsigned int cpu = smp_processor_id();
+        struct ucode_cpu_info *uci = &per_cpu(ucode_cpu_info, cpu);
+
         if ( start_update && microcode_ops->start_update )
             rc = microcode_ops->start_update();
 
         if ( rc )
             return rc;
 
-        return microcode_update_cpu(data, len);
+        spin_lock(&microcode_mutex);
+
+        rc = microcode_ops->collect_cpu_info(cpu, &uci->cpu_sig);
+        if ( likely(!rc) )
+            rc = microcode_ops->cpu_request_microcode(cpu, data, len);
+        else
+            __microcode_fini_cpu(cpu);
+
+        spin_unlock(&microcode_mutex);
+
+        if ( rc <= 0 )
+            return -EINVAL;
+
+        return microcode_update_cpu();
     }
     else
         return -ENOMEM;
diff --git a/xen/arch/x86/microcode_amd.c b/xen/arch/x86/microcode_amd.c
index 6e6598a..6d860f3 100644
--- a/xen/arch/x86/microcode_amd.c
+++ b/xen/arch/x86/microcode_amd.c
@@ -299,6 +299,10 @@ static int apply_microcode(unsigned int cpu)
 
     uci->cpu_sig.rev = rev;
 
+#if CONFIG_HVM
+    svm_host_osvw_init();
+#endif
+
     return 0;
 }
 
@@ -466,6 +470,7 @@ static int cpu_request_microcode(unsigned int cpu, const 
void *buf,
     struct ucode_cpu_info *uci = &per_cpu(ucode_cpu_info, cpu);
     unsigned int current_cpu_id;
     unsigned int equiv_cpu_id;
+    unsigned int matched_cnt = 0;
 
     /* We should bind the task to the CPU */
     BUG_ON(cpu != raw_smp_processor_id());
@@ -572,9 +577,7 @@ static int cpu_request_microcode(unsigned int cpu, const 
void *buf,
 
         if ( microcode_fits(mc_amd, cpu) )
         {
-            error = apply_microcode(cpu);
-            if ( error )
-                break;
+            matched_cnt++;
             applied_offset = last_offset;
         }
 
@@ -609,17 +612,13 @@ static int cpu_request_microcode(unsigned int cpu, const 
void *buf,
     }
 
   out:
-#if CONFIG_HVM
-    svm_host_osvw_init();
-#endif
-
     /*
      * In some cases we may return an error even if processor's microcode has
      * been updated. For example, the first patch in a container file is loaded
      * successfully but subsequent container file processing encounters a
      * failure.
      */
-    return error;
+    return !error ? matched_cnt : error;
 }
 
 static int start_update(void)
diff --git a/xen/arch/x86/microcode_intel.c b/xen/arch/x86/microcode_intel.c
index 1857332..a529623 100644
--- a/xen/arch/x86/microcode_intel.c
+++ b/xen/arch/x86/microcode_intel.c
@@ -466,10 +466,7 @@ static int cpu_request_microcode(unsigned int cpu, const 
void *buf,
     if ( offset < 0 )
         error = offset;
 
-    if ( !error && matching_count )
-        error = apply_microcode(cpu);
-
-    return error;
+    return !error ? matching_count : error;
 }
 
 static const struct microcode_ops microcode_intel_ops = {
-- 
1.8.3.1


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