From: Fenghua Yu <fenghua.yu@intel.com>
To: "Thomas Gleixner" <tglx@linutronix.de>,
"Ingo Molnar" <mingo@redhat.com>, "H Peter Anvin" <hpa@zytor.com>,
"Ravi V Shankar" <ravi.v.shankar@intel.com>,
"Ashok Raj" <ashok.raj@intel.com>
Cc: "linux-kernel" <linux-kernel@vger.kernel.org>,
"Fenghua Yu" <fenghua.yu@intel.com>
Subject: [PATCH 2/2] x86/cpufeatures: Enumerate MOVDIR64B instruction
Date: Wed, 24 Oct 2018 14:57:17 -0700 [thread overview]
Message-ID: <1540418237-125817-3-git-send-email-fenghua.yu@intel.com> (raw)
In-Reply-To: <1540418237-125817-1-git-send-email-fenghua.yu@intel.com>
MOVDIR64B moves 64-bytes as direct-store with 64-bytes write atomicity.
Direct store is implemented by using write combining (WC) for writing
data directly into memory without caching the data.
In low latency offload (e.g. Non-Volatile Memory, etc), MOVDIR64B writes
work descriptors (and data in some cases) to device-hosted work-queues
atomically without cache pollution.
Availability of the MOVDIR64B instruction is indicated by the
presence of the CPUID feature flag MOVDIR64B (CPUID.0x07.0x0:ECX[bit 28]).
Please check the latest Intel Architecture Instruction Set Extensions
and Future Features Programming Reference for more details on the CPUID
feature MOVDIR64B flag.
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
---
arch/x86/include/asm/cpufeatures.h | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index 90934ee7b79a..28c4a502b419 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -332,6 +332,7 @@
#define X86_FEATURE_RDPID (16*32+22) /* RDPID instruction */
#define X86_FEATURE_CLDEMOTE (16*32+25) /* CLDEMOTE instruction */
#define X86_FEATURE_MOVDIRI (16*32+27) /* MOVDIRI instruction */
+#define X86_FEATURE_MOVDIR64B (16*32+28) /* MOVDIR64B instruction */
/* AMD-defined CPU features, CPUID level 0x80000007 (EBX), word 17 */
#define X86_FEATURE_OVERFLOW_RECOV (17*32+ 0) /* MCA overflow recovery support */
--
2.5.0
next prev parent reply other threads:[~2018-10-24 22:01 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-24 21:57 [PATCH 0/2] x86: Enumerate direct stores instructions Fenghua Yu
2018-10-24 21:57 ` [PATCH 1/2] x86/cpufeatures: Enumerate MOVDIRI instruction Fenghua Yu
2018-10-25 5:45 ` [tip:x86/urgent] " tip-bot for Fenghua Yu
2018-10-24 21:57 ` Fenghua Yu [this message]
2018-10-25 5:46 ` [tip:x86/urgent] x86/cpufeatures: Enumerate MOVDIR64B instruction tip-bot for Fenghua Yu
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