linux-kernel - [PATCH 2/2] x86/microcode: Update the new microcode revision unconditionally

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Message-ID: <20180801154531.GE13988@nazgul.tnic>
Date:   Wed, 1 Aug 2018 17:45:31 +0200
From:   Borislav Petkov <bp@...en8.de>
To:     Prarit Bhargava <prarit@...hat.com>
Cc:     linux-edac@...r.kernel.org, linux-kernel@...r.kernel.org,
        sironi@...zon.de, tony.luck@...el.com
Subject: [PATCH 2/2] x86/microcode: Update the new microcode revision
 unconditionally

From: Filippo Sironi <sironi@...zon.de>

Handle the case where microcode gets loaded on the BSP's hyperthread
sibling first and the boot_cpu_data's microcode revision doesn't get
updated because of early exit due to the siblings sharing a microcode
engine.

For that, simply write the updated revision on all CPUs unconditionally.

Signed-off-by: Filippo Sironi <sironi@...zon.de>
Cc: prarit@...hat.com
Cc: stable@...r.kernel.org
Cc: x86-ml <x86@...nel.org>
Link: http://lkml.kernel.org/r/1533050970-14385-1-git-send-email-sironi@amazon.de
[ Massage everything a bit. ]
Signed-off-by: Borislav Petkov <bp@...e.de>
---
 arch/x86/kernel/cpu/microcode/amd.c   | 22 +++++++++++++---------
 arch/x86/kernel/cpu/microcode/intel.c | 13 ++++++++-----
 2 files changed, 21 insertions(+), 14 deletions(-)

diff --git a/arch/x86/kernel/cpu/microcode/amd.c b/arch/x86/kernel/cpu/microcode/amd.c
index 63b072377ba4..07b5fc00b188 100644
--- a/arch/x86/kernel/cpu/microcode/amd.c
+++ b/arch/x86/kernel/cpu/microcode/amd.c
@@ -504,6 +504,7 @@ static enum ucode_state apply_microcode_amd(int cpu)
 	struct microcode_amd *mc_amd;
 	struct ucode_cpu_info *uci;
 	struct ucode_patch *p;
+	enum ucode_state ret;
 	u32 rev, dummy;
 
 	BUG_ON(raw_smp_processor_id() != cpu);
@@ -521,9 +522,8 @@ static enum ucode_state apply_microcode_amd(int cpu)
 
 	/* need to apply patch? */
 	if (rev >= mc_amd->hdr.patch_id) {
-		c->microcode = rev;
-		uci->cpu_sig.rev = rev;
-		return UCODE_OK;
+		ret = UCODE_OK;
+		goto out;
 	}
 
 	if (__apply_microcode_amd(mc_amd)) {
@@ -531,17 +531,21 @@ static enum ucode_state apply_microcode_amd(int cpu)
 			cpu, mc_amd->hdr.patch_id);
 		return UCODE_ERROR;
 	}
-	pr_info("CPU%d: new patch_level=0x%08x\n", cpu,
-		mc_amd->hdr.patch_id);
 
-	uci->cpu_sig.rev = mc_amd->hdr.patch_id;
-	c->microcode = mc_amd->hdr.patch_id;
+	rev = mc_amd->hdr.patch_id;
+	ret = UCODE_UPDATED;
+
+	pr_info("CPU%d: new patch_level=0x%08x\n", cpu, rev);
+
+out:
+	uci->cpu_sig.rev = rev;
+	c->microcode	 = rev;
 
 	/* Update boot_cpu_data's revision too, if we're on the BSP: */
 	if (c->cpu_index == boot_cpu_data.cpu_index)
-		boot_cpu_data.microcode =  mc_amd->hdr.patch_id;
+		boot_cpu_data.microcode = rev;
 
-	return UCODE_UPDATED;
+	return ret;
 }
 
 static int install_equiv_cpu_table(const u8 *buf)
diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c
index 256d336cbc04..16936a24795c 100644
--- a/arch/x86/kernel/cpu/microcode/intel.c
+++ b/arch/x86/kernel/cpu/microcode/intel.c
@@ -795,6 +795,7 @@ static enum ucode_state apply_microcode_intel(int cpu)
 	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
 	struct cpuinfo_x86 *c = &cpu_data(cpu);
 	struct microcode_intel *mc;
+	enum ucode_state ret;
 	static int prev_rev;
 	u32 rev;
 
@@ -817,9 +818,8 @@ static enum ucode_state apply_microcode_intel(int cpu)
 	 */
 	rev = intel_get_microcode_revision();
 	if (rev >= mc->hdr.rev) {
-		uci->cpu_sig.rev = rev;
-		c->microcode = rev;
-		return UCODE_OK;
+		ret = UCODE_OK;
+		goto out;
 	}
 
 	/*
@@ -848,14 +848,17 @@ static enum ucode_state apply_microcode_intel(int cpu)
 		prev_rev = rev;
 	}
 
+	ret = UCODE_UPDATED;
+
+out:
 	uci->cpu_sig.rev = rev;
-	c->microcode = rev;
+	c->microcode	 = rev;
 
 	/* Update boot_cpu_data's revision too, if we're on the BSP: */
 	if (c->cpu_index == boot_cpu_data.cpu_index)
 		boot_cpu_data.microcode = rev;
 
-	return UCODE_UPDATED;
+	return ret;
 }
 
 static enum ucode_state generic_load_microcode(int cpu, void *data, size_t size,
-- 
2.18.0.321.gffc6fa0e3962


-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.
--