linux-kernel - [PATCH v2 2/2] x86/microcode/AMD: Clean the cache if update did not load microcode

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Message-ID: <20250327230503.1850368-3-boris.ostrovsky@oracle.com>
Date: Thu, 27 Mar 2025 19:05:03 -0400
From: Boris Ostrovsky <boris.ostrovsky@...cle.com>
To: linux-kernel@...r.kernel.org
Cc: bp@...en8.de, tglx@...utronix.de, mingo@...hat.com,
        dave.hansen@...ux.intel.com, x86@...nel.org, hpa@...or.com,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>
Subject: [PATCH v2 2/2] x86/microcode/AMD: Clean the cache if update did not load microcode

If microcode did not get loaded there is no reason to keep it in the cache.
Moreover, if loading failed it will not be possible to load an earlier
version of microcode since failed version will always be selected from
the cache on next reload attempt.

Since failed version is not easily avaialble at this point just clean the
whole cache. It will be rebuilt later if needed.

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@...cle.com>
---
 arch/x86/kernel/cpu/microcode/amd.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/arch/x86/kernel/cpu/microcode/amd.c b/arch/x86/kernel/cpu/microcode/amd.c
index b61028cf5c8a..57bd61f9c69b 100644
--- a/arch/x86/kernel/cpu/microcode/amd.c
+++ b/arch/x86/kernel/cpu/microcode/amd.c
@@ -1171,11 +1171,18 @@ static void microcode_fini_cpu_amd(int cpu)
 	uci->mc = NULL;
 }
 
+static void finalize_late_load_amd(int result)
+{
+	if (result)
+		cleanup();
+}
+
 static struct microcode_ops microcode_amd_ops = {
 	.request_microcode_fw	= request_microcode_amd,
 	.collect_cpu_info	= collect_cpu_info_amd,
 	.apply_microcode	= apply_microcode_amd,
 	.microcode_fini_cpu	= microcode_fini_cpu_amd,
+	.finalize_late_load	= finalize_late_load_amd,
 	.nmi_safe		= true,
 };
 
-- 
2.43.5