linux-kernel - [PATCH 2/7] x86/cpufeatures: Enumerate ENQCMD and ENQCMDS instructions

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Message-Id: <1585596788-193989-3-git-send-email-fenghua.yu@intel.com>
Date:   Mon, 30 Mar 2020 12:33:03 -0700
From:   Fenghua Yu <fenghua.yu@...el.com>
To:     "Thomas Gleixner" <tglx@...utronix.de>,
        "Ingo Molnar" <mingo@...hat.com>, "Borislav Petkov" <bp@...en8.de>,
        "H Peter Anvin" <hpa@...or.com>,
        "David Woodhouse" <dwmw2@...radead.org>,
        "Lu Baolu" <baolu.lu@...ux.intel.com>,
        "Dave Hansen" <dave.hansen@...el.com>,
        "Tony Luck" <tony.luck@...el.com>,
        "Ashok Raj" <ashok.raj@...el.com>,
        "Jacob Jun Pan" <jacob.jun.pan@...el.com>,
        "Dave Jiang" <dave.jiang@...el.com>,
        "Sohil Mehta" <sohil.mehta@...el.com>,
        "Ravi V Shankar" <ravi.v.shankar@...el.com>
Cc:     "linux-kernel" <linux-kernel@...r.kernel.org>,
        "x86" <x86@...nel.org>, iommu@...ts.linux-foundation.org,
        Fenghua Yu <fenghua.yu@...el.com>
Subject: [PATCH 2/7] x86/cpufeatures: Enumerate ENQCMD and ENQCMDS instructions

A user space application can execute ENQCMD instruction to submit work
to device. The kernel executes ENQCMDS instruction to submit work to
device.

There is a lot of other enabling needed for the instructions to actually
be usable in user space and the kernel, and that enabling is coming later
in the series and in device drivers.

The CPU feature flag is shown as "enqcmd" in /proc/cpuinfo.

Signed-off-by: Fenghua Yu <fenghua.yu@...el.com>
Reviewed-by: Tony Luck <tony.luck@...el.com>
---
 arch/x86/include/asm/cpufeatures.h | 1 +
 arch/x86/kernel/cpu/cpuid-deps.c   | 1 +
 2 files changed, 2 insertions(+)

diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index f3327cb56edf..d12ee3be1b93 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -349,6 +349,7 @@
 #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 */
+#define X86_FEATURE_ENQCMD		(16*32+29) /* ENQCMD and ENQCMDS instructions */
 
 /* AMD-defined CPU features, CPUID level 0x80000007 (EBX), word 17 */
 #define X86_FEATURE_OVERFLOW_RECOV	(17*32+ 0) /* MCA overflow recovery support */
diff --git a/arch/x86/kernel/cpu/cpuid-deps.c b/arch/x86/kernel/cpu/cpuid-deps.c
index 3cbe24ca80ab..3a02707c1f4d 100644
--- a/arch/x86/kernel/cpu/cpuid-deps.c
+++ b/arch/x86/kernel/cpu/cpuid-deps.c
@@ -69,6 +69,7 @@ static const struct cpuid_dep cpuid_deps[] = {
 	{ X86_FEATURE_CQM_MBM_TOTAL,		X86_FEATURE_CQM_LLC   },
 	{ X86_FEATURE_CQM_MBM_LOCAL,		X86_FEATURE_CQM_LLC   },
 	{ X86_FEATURE_AVX512_BF16,		X86_FEATURE_AVX512VL  },
+	{ X86_FEATURE_ENQCMD,			X86_FEATURE_XSAVES    },
 	{}
 };
 
-- 
2.19.1