--- arch/x86/kernel/cpu/mtrr/main.c

+++ arch/x86/kernel/cpu/mtrr/main.c

@@ -262,14 +262,24 @@ set_mtrr(unsigned int reg, unsigned long

/*

* HACK!

- * We use this same function to initialize the mtrrs on boot.

- * The state of the boot cpu's mtrrs has been saved, and we want

- * to replicate across all the APs.

- * If we're doing that @reg is set to something special...

+ *

+ * We use this same function to initialize the mtrrs during boot,

+ * resume, runtime cpu online and on an explicit request to set a

+ * specific MTRR.

+ *

+ * During boot or suspend, the state of the boot cpu's mtrrs has been

+ * saved, and we want to replicate that across all the cpus that come

+ * online (either at the end of boot or resume or during a runtime cpu

+ * online). If we're doing that, @reg is set to something special and on

+ * this cpu we still do mtrr_if->set_all(). During boot/resume, this

+ * is unnecessary if at this point we are still on the cpu that started

+ * the boot/resume sequence. But there is no guarantee that we are still

+ * on the same cpu. So we do mtrr_if->set_all() on this cpu aswell to be

+ * sure that we are in sync with everyone else.

*/

if (reg != ~0U)

mtrr_if->set(reg, base, size, type);

- else if (!mtrr_aps_delayed_init)

+ else

mtrr_if->set_all();

/* Wait for the others */