1 files changed, 7 insertions, 1 deletions

diff --git a/arch/x86/kernel/microcode_core.c b/arch/x86/kernel/microcode_core.c
index f9242800bc84..f2d2a664e797 100644
--- a/arch/x86/kernel/microcode_core.c
+++ b/arch/x86/kernel/microcode_core.c
@@ -483,7 +483,13 @@ mc_cpu_callback(struct notifier_block *nb, unsigned long action, void *hcpu)
                 sysfs_remove_group(&sys_dev->kobj, &mc_attr_group);
                 pr_debug("CPU%d removed\n", cpu);
                 break;
-        case CPU_DEAD:
+
+        /*
+         * When a CPU goes offline, don't free up or invalidate the copy of
+         * the microcode in kernel memory, so that we can reuse it when the
+         * CPU comes back online without unnecessarily requesting the userspace
+         * for it again.
+         */
         case CPU_UP_CANCELED_FROZEN:
                 /* The CPU refused to come up during a system resume */
                 microcode_fini_cpu(cpu);