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From: Kuppuswamy Sathyanarayanan  <sathyanarayanan.kuppuswamy@linux.intel.com>
To: Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	Peter Zijlstra <peterz@infradead.org>,
	Andy Lutomirski <luto@kernel.org>
Cc: Peter H Anvin <hpa@zytor.com>,
	Dave Hansen <dave.hansen@intel.com>,
	Tony Luck <tony.luck@intel.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Andi Kleen <ak@linux.intel.com>,
	Kirill Shutemov <kirill.shutemov@linux.intel.com>,
	Sean Christopherson <seanjc@google.com>,
	Kuppuswamy Sathyanarayanan <knsathya@kernel.org>,
	x86@kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v5 03/12] x86/cpufeatures: Add TDX Guest CPU feature
Date: Wed,  4 Aug 2021 11:13:20 -0700	[thread overview]
Message-ID: <20210804181329.2899708-4-sathyanarayanan.kuppuswamy@linux.intel.com> (raw)
In-Reply-To: <20210804181329.2899708-1-sathyanarayanan.kuppuswamy@linux.intel.com>

Add CPU feature detection for Trusted Domain Extensions support. TDX
feature adds capabilities to keep guest register state and memory
isolated from hypervisor.

For TDX guest platforms, executing CPUID(eax=0x21, ecx=0) will return
following values in EAX, EBX, ECX and EDX.

EAX:  Maximum sub-leaf number:  0
EBX/EDX/ECX:  Vendor string:

EBX =  "Inte"
EDX =  "lTDX"
ECX =  "    "

So when above condition is true, set X86_FEATURE_TDX_GUEST feature cap
bit.

Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
---

Changes since v4:
 * Moved tdx_early_init() below copy_bootdata() because of
   cmdline and IDT dependencies.

Changes since v3:
 * Fixed order of string cpuid_count() call.

Changes since v2:
 * Fixed debug prints as per Borislav suggestion.

Changes since v1:
 * Fixed commit log issues reported by Borislav.
 * Moved header file include to the start of tdx.h.
 * Added pr_fmt for TDX.
 * Simplified cpuid_has_tdx_guest() implementation as per
   Borislav comments.

 arch/x86/include/asm/cpufeatures.h |  1 +
 arch/x86/include/asm/tdx.h         | 20 ++++++++++++++++++++
 arch/x86/kernel/Makefile           |  1 +
 arch/x86/kernel/head64.c           |  3 +++
 arch/x86/kernel/tdx.c              | 29 +++++++++++++++++++++++++++++
 5 files changed, 54 insertions(+)
 create mode 100644 arch/x86/include/asm/tdx.h
 create mode 100644 arch/x86/kernel/tdx.c

diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index d0ce5cfd3ac1..84997abeb401 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -238,6 +238,7 @@
 #define X86_FEATURE_VMW_VMMCALL		( 8*32+19) /* "" VMware prefers VMMCALL hypercall instruction */
 #define X86_FEATURE_PVUNLOCK		( 8*32+20) /* "" PV unlock function */
 #define X86_FEATURE_VCPUPREEMPT		( 8*32+21) /* "" PV vcpu_is_preempted function */
+#define X86_FEATURE_TDX_GUEST		( 8*32+22) /* Trusted Domain Extensions Guest */
 
 /* Intel-defined CPU features, CPUID level 0x00000007:0 (EBX), word 9 */
 #define X86_FEATURE_FSGSBASE		( 9*32+ 0) /* RDFSBASE, WRFSBASE, RDGSBASE, WRGSBASE instructions*/
diff --git a/arch/x86/include/asm/tdx.h b/arch/x86/include/asm/tdx.h
new file mode 100644
index 000000000000..c738bde944d1
--- /dev/null
+++ b/arch/x86/include/asm/tdx.h
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (C) 2020 Intel Corporation */
+#ifndef _ASM_X86_TDX_H
+#define _ASM_X86_TDX_H
+
+#include <linux/cpufeature.h>
+
+#define TDX_CPUID_LEAF_ID	0x21
+
+#ifdef CONFIG_INTEL_TDX_GUEST
+
+void __init tdx_early_init(void);
+
+#else
+
+static inline void tdx_early_init(void) { };
+
+#endif /* CONFIG_INTEL_TDX_GUEST */
+
+#endif /* _ASM_X86_TDX_H */
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 3e625c61f008..b49110bd50d9 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -127,6 +127,7 @@ obj-$(CONFIG_PARAVIRT_CLOCK)	+= pvclock.o
 obj-$(CONFIG_X86_PMEM_LEGACY_DEVICE) += pmem.o
 
 obj-$(CONFIG_JAILHOUSE_GUEST)	+= jailhouse.o
+obj-$(CONFIG_INTEL_TDX_GUEST)	+= tdx.o
 
 obj-$(CONFIG_EISA)		+= eisa.o
 obj-$(CONFIG_PCSPKR_PLATFORM)	+= pcspeaker.o
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index de01903c3735..f41f3dac1318 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -40,6 +40,7 @@
 #include <asm/extable.h>
 #include <asm/trapnr.h>
 #include <asm/sev.h>
+#include <asm/tdx.h>
 
 /*
  * Manage page tables very early on.
@@ -495,6 +496,8 @@ asmlinkage __visible void __init x86_64_start_kernel(char * real_mode_data)
 
 	copy_bootdata(__va(real_mode_data));
 
+	tdx_early_init();
+
 	/*
 	 * Load microcode early on BSP.
 	 */
diff --git a/arch/x86/kernel/tdx.c b/arch/x86/kernel/tdx.c
new file mode 100644
index 000000000000..39dd1515b131
--- /dev/null
+++ b/arch/x86/kernel/tdx.c
@@ -0,0 +1,29 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (C) 2020 Intel Corporation */
+
+#undef pr_fmt
+#define pr_fmt(fmt)     "x86/tdx: " fmt
+
+#include <asm/tdx.h>
+
+static inline bool cpuid_has_tdx_guest(void)
+{
+	u32 eax, sig[3];
+
+	if (cpuid_eax(0) < TDX_CPUID_LEAF_ID)
+		return false;
+
+	cpuid_count(TDX_CPUID_LEAF_ID, 0, &eax, &sig[0], &sig[2], &sig[1]);
+
+	return !memcmp("IntelTDX    ", sig, 12);
+}
+
+void __init tdx_early_init(void)
+{
+	if (!cpuid_has_tdx_guest())
+		return;
+
+	setup_force_cpu_cap(X86_FEATURE_TDX_GUEST);
+
+	pr_info("Guest initialized\n");
+}
-- 
2.25.1


  parent reply	other threads:[~2021-08-04 18:14 UTC|newest]

Thread overview: 72+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-04 18:13 [PATCH v5 00/12] Add TDX Guest Support (Initial support) Kuppuswamy Sathyanarayanan
2021-08-04 18:13 ` [PATCH v5 01/12] x86/paravirt: Move halt paravirt calls under CONFIG_PARAVIRT Kuppuswamy Sathyanarayanan
2021-08-12  7:18   ` Borislav Petkov
2021-08-12 17:17     ` Kuppuswamy, Sathyanarayanan
2021-08-17 12:50     ` Juergen Gross
2021-08-17 13:16       ` Kuppuswamy, Sathyanarayanan
2021-08-17 13:28         ` Juergen Gross
2021-08-17 13:39           ` Kuppuswamy, Sathyanarayanan
2021-08-17 13:47             ` Juergen Gross
2021-08-17 13:50               ` Kuppuswamy, Sathyanarayanan
2021-08-04 18:13 ` [PATCH v5 02/12] x86/tdx: Introduce INTEL_TDX_GUEST config option Kuppuswamy Sathyanarayanan
2021-08-04 18:13 ` Kuppuswamy Sathyanarayanan [this message]
2021-08-12  7:39   ` [PATCH v5 03/12] x86/cpufeatures: Add TDX Guest CPU feature Borislav Petkov
2021-08-04 18:13 ` [PATCH v5 04/12] x86/tdx: Add protected guest support for TDX guest Kuppuswamy Sathyanarayanan
2021-08-04 21:59   ` Sean Christopherson
2021-08-04 22:03     ` Dave Hansen
2021-08-04 22:26       ` Kuppuswamy, Sathyanarayanan
2021-08-04 22:42         ` Sean Christopherson
2021-08-04 23:00           ` Kuppuswamy, Sathyanarayanan
2021-08-12  7:53             ` Borislav Petkov
2021-08-12 17:18               ` Kuppuswamy, Sathyanarayanan
2021-08-20 14:28                 ` Borislav Petkov
2021-08-20 16:42                   ` Kuppuswamy, Sathyanarayanan
2021-08-20 16:59                     ` Borislav Petkov
2021-08-20 17:11                       ` Kuppuswamy, Sathyanarayanan
2021-08-04 18:13 ` [PATCH v5 05/12] x86/tdx: Add __tdx_module_call() and __tdx_hypercall() helper functions Kuppuswamy Sathyanarayanan
2021-08-20 15:16   ` Borislav Petkov
2021-08-04 18:13 ` [PATCH v5 06/12] x86/tdx: Get TD execution environment information via TDINFO Kuppuswamy Sathyanarayanan
2021-08-04 22:38   ` Sean Christopherson
2021-08-20 17:13   ` Borislav Petkov
2021-08-20 17:31     ` Kuppuswamy, Sathyanarayanan
2021-08-20 17:35       ` Borislav Petkov
2021-08-20 18:29         ` Kuppuswamy, Sathyanarayanan
2021-08-20 18:58           ` Andi Kleen
2021-08-20 19:01             ` Kuppuswamy, Sathyanarayanan
2021-08-04 18:13 ` [PATCH v5 07/12] x86/traps: Add #VE support for TDX guest Kuppuswamy Sathyanarayanan
2021-08-24 10:17   ` Borislav Petkov
2021-08-24 17:32     ` Kuppuswamy, Sathyanarayanan
2021-08-24 17:36       ` Dave Hansen
2021-08-24 17:46       ` Borislav Petkov
2021-09-02 15:24         ` Kuppuswamy, Sathyanarayanan
2021-09-03 10:17           ` Borislav Petkov
2021-08-04 18:13 ` [PATCH v5 08/12] x86/tdx: Add HLT " Kuppuswamy Sathyanarayanan
2021-08-24 16:10   ` Borislav Petkov
2021-08-24 17:06     ` Sean Christopherson
2021-08-24 17:25       ` Andi Kleen
2021-08-24 17:27       ` Borislav Petkov
2021-08-24 17:47         ` Sean Christopherson
2021-08-24 17:50           ` Borislav Petkov
2021-08-31 20:49         ` Kuppuswamy, Sathyanarayanan
2021-09-01  7:42           ` Borislav Petkov
2021-08-24 18:18       ` Kuppuswamy, Sathyanarayanan
2021-08-24 18:28         ` Andi Kleen
2021-08-24 17:35     ` Kuppuswamy, Sathyanarayanan
2021-08-24 17:48       ` Borislav Petkov
2021-08-04 18:13 ` [PATCH v5 09/12] x86/tdx: Wire up KVM hypercalls Kuppuswamy Sathyanarayanan
2021-08-24 16:34   ` Borislav Petkov
2021-08-24 18:11     ` Kuppuswamy, Sathyanarayanan
2021-08-24 18:29       ` Borislav Petkov
2021-08-24 19:11         ` Kuppuswamy, Sathyanarayanan
2021-08-24 19:39           ` Borislav Petkov
2021-08-04 18:13 ` [PATCH v5 10/12] x86/tdx: Add MSR support for TDX guest Kuppuswamy Sathyanarayanan
2021-08-24 16:55   ` Borislav Petkov
2021-08-24 18:12     ` Kuppuswamy, Sathyanarayanan
2021-08-04 18:13 ` [PATCH v5 11/12] x86/tdx: Don't write CSTAR MSR on Intel Kuppuswamy Sathyanarayanan
2021-08-04 18:31   ` Sean Christopherson
2021-08-04 21:03     ` Kuppuswamy, Sathyanarayanan
2021-08-04 21:44       ` Sean Christopherson
2021-08-04 21:48       ` Dave Hansen
2021-08-04 22:23         ` Kuppuswamy, Sathyanarayanan
2021-08-04 18:13 ` [PATCH v5 12/12] x86/tdx: Handle CPUID via #VE Kuppuswamy Sathyanarayanan
2021-08-24 17:48   ` Borislav Petkov

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