linux-kernel - [PATCH v10 26/38] x86/CPU/AMD: Make the microcode level available earlier in the boot

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Date:   Mon, 17 Jul 2017 16:10:23 -0500
From:   Tom Lendacky <thomas.lendacky@....com>
To:     x86@...nel.org, linux-kernel@...r.kernel.org,
        linux-arch@...r.kernel.org, linux-efi@...r.kernel.org,
        linux-doc@...r.kernel.org, linux-mm@...ck.org, kvm@...r.kernel.org,
        kasan-dev@...glegroups.com
Cc:     Radim Krčmář <rkrcmar@...hat.com>,
        Arnd Bergmann <arnd@...db.de>,
        Jonathan Corbet <corbet@....net>,
        Matt Fleming <matt@...eblueprint.co.uk>,
        Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
        Andrey Ryabinin <aryabinin@...tuozzo.com>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Andy Lutomirski <luto@...nel.org>,
        "H. Peter Anvin" <hpa@...or.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Alexander Potapenko <glider@...gle.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Dmitry Vyukov <dvyukov@...gle.com>,
        Rik van Riel <riel@...hat.com>,
        Larry Woodman <lwoodman@...hat.com>,
        Dave Young <dyoung@...hat.com>,
        Toshimitsu Kani <toshi.kani@....com>,
        "Michael S. Tsirkin" <mst@...hat.com>,
        Brijesh Singh <brijesh.singh@....com>
Subject: [PATCH v10 26/38] x86/CPU/AMD: Make the microcode level available earlier in the boot

Move the setting of the cpuinfo_x86.microcode field from amd_init() to
early_amd_init() so that it is available earlier in the boot process. This
avoids having to read MSR_AMD64_PATCH_LEVEL directly during early boot.

Reviewed-by: Borislav Petkov <bp@...e.de>
Signed-off-by: Tom Lendacky <thomas.lendacky@....com>
---
 arch/x86/kernel/cpu/amd.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index e41670e..110ca5d 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -548,8 +548,12 @@ static void bsp_init_amd(struct cpuinfo_x86 *c)
 
 static void early_init_amd(struct cpuinfo_x86 *c)
 {
+	u32 dummy;
+
 	early_init_amd_mc(c);
 
+	rdmsr_safe(MSR_AMD64_PATCH_LEVEL, &c->microcode, &dummy);
+
 	/*
 	 * c->x86_power is 8000_0007 edx. Bit 8 is TSC runs at constant rate
 	 * with P/T states and does not stop in deep C-states
@@ -751,8 +755,6 @@ static void init_amd_bd(struct cpuinfo_x86 *c)
 
 static void init_amd(struct cpuinfo_x86 *c)
 {
-	u32 dummy;
-
 	early_init_amd(c);
 
 	/*
@@ -814,8 +816,6 @@ static void init_amd(struct cpuinfo_x86 *c)
 	if (c->x86 > 0x11)
 		set_cpu_cap(c, X86_FEATURE_ARAT);
 
-	rdmsr_safe(MSR_AMD64_PATCH_LEVEL, &c->microcode, &dummy);
-
 	/* 3DNow or LM implies PREFETCHW */
 	if (!cpu_has(c, X86_FEATURE_3DNOWPREFETCH))
 		if (cpu_has(c, X86_FEATURE_3DNOW) || cpu_has(c, X86_FEATURE_LM))
-- 
1.9.1