x86/microcode: Update the new microcode revision unconditionally

Handle the case where microcode gets loaded on the BSP's hyperthread
sibling first and the boot_cpu_data's microcode revision doesn't get
updated because of early exit due to the siblings sharing a microcode
engine.

For that, simply write the updated revision on all CPUs unconditionally.

Signed-off-by: Filippo Sironi <sironi@amazon.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: prarit@redhat.com
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1533050970-14385-1-git-send-email-sironi@amazon.de

1 files changed, 8 insertions, 5 deletions

diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c
index 256d336cbc04..16936a24795c 100644
--- a/arch/x86/kernel/cpu/microcode/intel.c
+++ b/arch/x86/kernel/cpu/microcode/intel.c
@@ -795,6 +795,7 @@ static enum ucode_state apply_microcode_intel(int cpu)
         struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
         struct cpuinfo_x86 *c = &cpu_data(cpu);
         struct microcode_intel *mc;
+        enum ucode_state ret;
         static int prev_rev;
         u32 rev;
 
@@ -817,9 +818,8 @@ static enum ucode_state apply_microcode_intel(int cpu)
          */
         rev = intel_get_microcode_revision();
         if (rev >= mc->hdr.rev) {
-                uci->cpu_sig.rev = rev;
-                c->microcode = rev;
-                return UCODE_OK;
+                ret = UCODE_OK;
+                goto out;
         }
 
         /*
@@ -848,14 +848,17 @@ static enum ucode_state apply_microcode_intel(int cpu)
                 prev_rev = rev;
         }
 
+        ret = UCODE_UPDATED;
+
+out:
         uci->cpu_sig.rev = rev;
-        c->microcode = rev;
+        c->microcode     = rev;
 
         /* Update boot_cpu_data's revision too, if we're on the BSP: */
         if (c->cpu_index == boot_cpu_data.cpu_index)
                 boot_cpu_data.microcode = rev;
 
-        return UCODE_UPDATED;
+        return ret;
 }
 
 static enum ucode_state generic_load_microcode(int cpu, void *data, size_t size,