linux-kernel - [PATCH 2/3] x86/msr: Add wrmsrl_val_on

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Message-Id: <20200610110037.11853-3-bp@alien8.de>
Date:   Wed, 10 Jun 2020 13:00:36 +0200
From:   Borislav Petkov <bp@...en8.de>
To:     X86 ML <x86@...nel.org>
Cc:     Tom Lendacky <thomas.lendacky@....com>,
        LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH 2/3] x86/msr: Add wrmsrl_val_on_cpus()

From: Borislav Petkov <bp@...e.de>

Add a helper which writes the same MSR value on a set of CPUs.

Signed-off-by: Borislav Petkov <bp@...e.de>
---
 arch/x86/include/asm/msr.h |  8 ++++++++
 arch/x86/lib/msr-smp.c     | 15 +++++++++++++++
 2 files changed, 23 insertions(+)

diff --git a/arch/x86/include/asm/msr.h b/arch/x86/include/asm/msr.h
index 86f20d520a07..71393a4c2104 100644
--- a/arch/x86/include/asm/msr.h
+++ b/arch/x86/include/asm/msr.h
@@ -342,6 +342,7 @@ int rdmsrl_on_cpu(unsigned int cpu, u32 msr_no, u64 *q);
 int wrmsrl_on_cpu(unsigned int cpu, u32 msr_no, u64 q);
 void rdmsr_on_cpus(const struct cpumask *mask, u32 msr_no, struct msr *msrs);
 void wrmsr_on_cpus(const struct cpumask *mask, u32 msr_no, struct msr *msrs);
+void wrmsrl_val_on_cpus(const struct cpumask *mask, u32 msr_no, u64 reg_val);
 int rdmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h);
 int wrmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h);
 int rdmsrl_safe_on_cpu(unsigned int cpu, u32 msr_no, u64 *q);
@@ -379,6 +380,13 @@ static inline void wrmsr_on_cpus(const struct cpumask *m, u32 msr_no,
 {
 	wrmsr_on_cpu(0, msr_no, msrs[0].l, msrs[0].h);
 }
+
+static inline void wrmsrl_val_on_cpus(const struct cpumask *mask, u32 msr_no,
+				      u64 reg_val)
+{
+	wrmsrl(msr_no, reg_val);
+}
+
 static inline int rdmsr_safe_on_cpu(unsigned int cpu, u32 msr_no,
 				    u32 *l, u32 *h)
 {
diff --git a/arch/x86/lib/msr-smp.c b/arch/x86/lib/msr-smp.c
index 15e1157d6b29..f67ee2fdec69 100644
--- a/arch/x86/lib/msr-smp.c
+++ b/arch/x86/lib/msr-smp.c
@@ -149,6 +149,21 @@ void wrmsr_on_cpus(const struct cpumask *mask, u32 msr_no, struct msr *msrs)
 }
 EXPORT_SYMBOL(wrmsr_on_cpus);
 
+/*
+ * wrmsr a single MSR value on a bunch of CPUs. To be used for MSRs which are
+ * the same on each core.
+ *
+ * @mask:       which CPUs
+ * @msr_no:     which MSR
+ * @reg_val:	MSR value
+ *
+ */
+void wrmsrl_val_on_cpus(const struct cpumask *mask, u32 msr_no, u64 reg_val)
+{
+	__rwmsr_on_cpus(mask, msr_no, NULL, reg_val, __wrmsr_on_cpu);
+}
+EXPORT_SYMBOL(wrmsrl_val_on_cpus);
+
 struct msr_info_completion {
 	struct msr_info		msr;
 	struct completion	done;
-- 
2.21.0