From 596bd0589ad8ee1df78133af740f1d29b235fb66 Mon Sep 17 00:00:00 2001
From: Bin Meng <bmeng.cn@gmail.com>
Date: Sat, 31 Jul 2021 16:45:24 +0800
Subject: [PATCH] x86: mtrr: Do not clear the unused ones in mtrr_commit()
Current mtrr_commit() logic assumes that MTRR MSRs are programmed
consecutively from index 0 to its maximum number, and whenever it
detects an unused one, it clears all other MTRRs starting from that
one. However this may not always be the case.
In fact, the clear is not much helpful because these MTRRs come out
of reset as disabled already. Drop the clear codes.
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Tested on chromebook_coral, chromebook_samus, chromebook_link, minnowmax
Tested-by: Simon Glass <sjg@chromium.org>
---
arch/x86/cpu/mtrr.c | 4 ----
1 file changed, 4 deletions(-)
diff --git a/arch/x86/cpu/mtrr.c b/arch/x86/cpu/mtrr.c
index 166aff380c..73cf7bb2be 100644
--- a/arch/x86/cpu/mtrr.c
+++ b/arch/x86/cpu/mtrr.c
@@ -157,10 +157,6 @@ int mtrr_commit(bool do_caches)
for (i = 0; i < gd->arch.mtrr_req_count; i++, req++)
set_var_mtrr(i, req->type, req->start, req->size);
- /* Clear the ones that are unused */
- debug("clear\n");
- for (; i < mtrr_get_var_count(); i++)
- wrmsrl(MTRR_PHYS_MASK_MSR(i), 0);
debug("close\n");
mtrr_close(&state, do_caches);
debug("mtrr done\n");
--
2.39.5