linux-kernel - [PATCH v40 04/24] x86/cpufeatures: x86/msr: Add Intel SGX hardware bits

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Message-Id: <20201104145430.300542-5-jarkko.sakkinen@linux.intel.com>
Date:   Wed,  4 Nov 2020 16:54:10 +0200
From:   Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
To:     x86@...nel.org, linux-sgx@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        Borislav Petkov <bp@...en8.de>,
        Jethro Beekman <jethro@...tanix.com>,
        Darren Kenny <darren.kenny@...cle.com>,
        Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>,
        akpm@...ux-foundation.org, andriy.shevchenko@...ux.intel.com,
        asapek@...gle.com, cedric.xing@...el.com, chenalexchen@...gle.com,
        conradparker@...gle.com, cyhanish@...gle.com,
        dave.hansen@...el.com, haitao.huang@...el.com, kai.huang@...el.com,
        kai.svahn@...el.com, kmoy@...gle.com, ludloff@...gle.com,
        luto@...nel.org, nhorman@...hat.com, npmccallum@...hat.com,
        puiterwijk@...hat.com, rientjes@...gle.com, tglx@...utronix.de,
        yaozhangx@...gle.com, mikko.ylinen@...el.com
Subject: [PATCH v40 04/24] x86/cpufeatures: x86/msr: Add Intel SGX hardware bits

From: Sean Christopherson <sean.j.christopherson@...el.com>

Populate X86_FEATURE_SGX feature from CPUID and tie it to the Kconfig
option with disabled-features.h.

IA32_FEATURE_CONTROL.SGX_ENABLE must be examined in addition to the CPUID
bits to enable full SGX support.  The BIOS must both set this bit and lock
IA32_FEATURE_CONTROL for SGX to be supported (Intel SDM section 36.7.1).
The setting or clearing of this bit has no impact on the CPUID bits above,
which is why it needs to be detected separately.

Reviewed-by: Borislav Petkov <bp@...en8.de>
Acked-by: Jethro Beekman <jethro@...tanix.com>
Reviewed-by: Darren Kenny <darren.kenny@...cle.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@...el.com>
Co-developed-by: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
---
Changes from v39:
* Remove X86_FEATURE_SGX{1, 2}. They were only mistakenly being used for
  model-specific errata detection.  Further, the errata does not occur
  on any processors that this implementation supports.  Later patches
  ignore the errata, so remove the CPUID bits.

 arch/x86/include/asm/cpufeatures.h       | 1 +
 arch/x86/include/asm/disabled-features.h | 8 +++++++-
 arch/x86/include/asm/msr-index.h         | 1 +
 3 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index dad350d42ecf..1181f5c7bbef 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -241,6 +241,7 @@
 /* Intel-defined CPU features, CPUID level 0x00000007:0 (EBX), word 9 */
 #define X86_FEATURE_FSGSBASE		( 9*32+ 0) /* RDFSBASE, WRFSBASE, RDGSBASE, WRGSBASE instructions*/
 #define X86_FEATURE_TSC_ADJUST		( 9*32+ 1) /* TSC adjustment MSR 0x3B */
+#define X86_FEATURE_SGX			( 9*32+ 2) /* Software Guard Extensions */
 #define X86_FEATURE_BMI1		( 9*32+ 3) /* 1st group bit manipulation extensions */
 #define X86_FEATURE_HLE			( 9*32+ 4) /* Hardware Lock Elision */
 #define X86_FEATURE_AVX2		( 9*32+ 5) /* AVX2 instructions */
diff --git a/arch/x86/include/asm/disabled-features.h b/arch/x86/include/asm/disabled-features.h
index 5861d34f9771..7947cb1782da 100644
--- a/arch/x86/include/asm/disabled-features.h
+++ b/arch/x86/include/asm/disabled-features.h
@@ -62,6 +62,12 @@
 # define DISABLE_ENQCMD (1 << (X86_FEATURE_ENQCMD & 31))
 #endif
 
+#ifdef CONFIG_X86_SGX
+# define DISABLE_SGX	0
+#else
+# define DISABLE_SGX	(1 << (X86_FEATURE_SGX & 31))
+#endif
+
 /*
  * Make sure to add features to the correct mask
  */
@@ -74,7 +80,7 @@
 #define DISABLED_MASK6	0
 #define DISABLED_MASK7	(DISABLE_PTI)
 #define DISABLED_MASK8	0
-#define DISABLED_MASK9	(DISABLE_SMAP)
+#define DISABLED_MASK9	(DISABLE_SMAP|DISABLE_SGX)
 #define DISABLED_MASK10	0
 #define DISABLED_MASK11	0
 #define DISABLED_MASK12	0
diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index 972a34d93505..258d555d22f2 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -609,6 +609,7 @@
 #define FEAT_CTL_LOCKED				BIT(0)
 #define FEAT_CTL_VMX_ENABLED_INSIDE_SMX		BIT(1)
 #define FEAT_CTL_VMX_ENABLED_OUTSIDE_SMX	BIT(2)
+#define FEAT_CTL_SGX_ENABLED			BIT(18)
 #define FEAT_CTL_LMCE_ENABLED			BIT(20)
 
 #define MSR_IA32_TSC_ADJUST             0x0000003b
-- 
2.27.0