[PATCH 17/22] x86: mtrr: Update MTRRs on all CPUs

Simon Glass sjg at chromium.org
Fri May 22 04:23:21 CEST 2020


When the boot CPU MTRRs are updated, perform the same update on all other
CPUs so they are kept in sync.

This avoids kernel warnings about mismatched MTRRs.

Signed-off-by: Simon Glass <sjg at chromium.org>
---

 arch/x86/cpu/mtrr.c | 57 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 57 insertions(+)

diff --git a/arch/x86/cpu/mtrr.c b/arch/x86/cpu/mtrr.c
index 11f3ef08172..a48c9d8232e 100644
--- a/arch/x86/cpu/mtrr.c
+++ b/arch/x86/cpu/mtrr.c
@@ -74,10 +74,61 @@ void mtrr_save_all(struct mtrr_info *info)
 	}
 }
 
+void mtrr_load_all(struct mtrr_info *info)
+{
+	struct mtrr_state state;
+	int i;
+
+	for (i = 0; i < MTRR_COUNT; i++) {
+		mtrr_open(&state, true);
+		wrmsrl(MTRR_PHYS_BASE_MSR(i), info->mtrr[i].base);
+		wrmsrl(MTRR_PHYS_MASK_MSR(i), info->mtrr[i].mask);
+		mtrr_close(&state, true);
+	}
+}
+
+static void save_mtrrs(void *arg)
+{
+	struct mtrr_info *info = arg;
+
+	mtrr_save_all(info);
+}
+
+static void load_mtrrs(void *arg)
+{
+	struct mtrr_info *info = arg;
+
+	mtrr_load_all(info);
+}
+
+/**
+ * mtrr_copy_to_aps() - Copy the MTRRs from the boot CPU to other CPUs
+ *
+ * @return 0 on success, -ve on failure
+ */
+static int mtrr_copy_to_aps(void)
+{
+	struct mtrr_info info;
+	int ret;
+
+	ret = mp_run_on_cpus(MP_SELECT_BSP, save_mtrrs, &info);
+	if (ret == -ENXIO)
+		return 0;
+	else if (ret)
+		return log_msg_ret("bsp", ret);
+
+	ret = mp_run_on_cpus(MP_SELECT_APS, load_mtrrs, &info);
+	if (ret)
+		return log_msg_ret("bsp", ret);
+
+	return 0;
+}
+
 int mtrr_commit(bool do_caches)
 {
 	struct mtrr_request *req = gd->arch.mtrr_req;
 	struct mtrr_state state;
+	int ret;
 	int i;
 
 	debug("%s: enabled=%d, count=%d\n", __func__, gd->arch.has_mtrr,
@@ -99,6 +150,12 @@ int mtrr_commit(bool do_caches)
 	mtrr_close(&state, do_caches);
 	debug("mtrr done\n");
 
+	if (gd->flags & GD_FLG_RELOC) {
+		ret = mtrr_copy_to_aps();
+		if (ret)
+			return log_msg_ret("copy", ret);
+	}
+
 	return 0;
 }
 
-- 
2.27.0.rc0.183.gde8f92d652-goog



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