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Date: Sat, 09 Apr 2022 01:27:43 -0000
From: "tip-bot2 for Kuppuswamy Sathyanarayanan" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Kuppuswamy Sathyanarayanan
<sathyanarayanan.kuppuswamy@...ux.intel.com>,
"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
Dave Hansen <dave.hansen@...ux.intel.com>,
Andi Kleen <ak@...ux.intel.com>,
Tony Luck <tony.luck@...el.com>, Borislav Petkov <bp@...e.de>,
Thomas Gleixner <tglx@...utronix.de>, x86@...nel.org,
linux-kernel@...r.kernel.org
Subject: [tip: x86/tdx] x86/tdx: Detect running as a TDX guest in early boot
The following commit has been merged into the x86/tdx branch of tip:
Commit-ID: 59bd54a84d15e9335de5b8abe7b3b9713a36b99b
Gitweb: https://git.kernel.org/tip/59bd54a84d15e9335de5b8abe7b3b9713a36b99b
Author: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@...ux.intel.com>
AuthorDate: Wed, 06 Apr 2022 02:29:10 +03:00
Committer: Dave Hansen <dave.hansen@...ux.intel.com>
CommitterDate: Thu, 07 Apr 2022 08:27:50 -07:00
x86/tdx: Detect running as a TDX guest in early boot
In preparation of extending cc_platform_has() API to support TDX guest,
use CPUID instruction to detect support for TDX guests in the early
boot code (via tdx_early_init()). Since copy_bootdata() is the first
user of cc_platform_has() API, detect the TDX guest status before it.
Define a synthetic feature flag (X86_FEATURE_TDX_GUEST) and set this
bit in a valid TDX guest platform.
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@...ux.intel.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@...ux.intel.com>
Reviewed-by: Andi Kleen <ak@...ux.intel.com>
Reviewed-by: Tony Luck <tony.luck@...el.com>
Reviewed-by: Dave Hansen <dave.hansen@...ux.intel.com>
Reviewed-by: Borislav Petkov <bp@...e.de>
Reviewed-by: Thomas Gleixner <tglx@...utronix.de>
Link: https://lkml.kernel.org/r/20220405232939.73860-2-kirill.shutemov@linux.intel.com
---
arch/x86/Kconfig | 12 ++++++++++++
arch/x86/coco/Makefile | 2 ++
arch/x86/coco/tdx/Makefile | 3 +++
arch/x86/coco/tdx/tdx.c | 22 ++++++++++++++++++++++
arch/x86/include/asm/cpufeatures.h | 1 +
arch/x86/include/asm/disabled-features.h | 8 +++++++-
arch/x86/include/asm/tdx.h | 21 +++++++++++++++++++++
arch/x86/kernel/head64.c | 4 ++++
8 files changed, 72 insertions(+), 1 deletion(-)
create mode 100644 arch/x86/coco/tdx/Makefile
create mode 100644 arch/x86/coco/tdx/tdx.c
create mode 100644 arch/x86/include/asm/tdx.h
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index b0142e0..4ae2732 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -878,6 +878,18 @@ config ACRN_GUEST
IOT with small footprint and real-time features. More details can be
found in https://projectacrn.org/.
+config INTEL_TDX_GUEST
+ bool "Intel TDX (Trust Domain Extensions) - Guest Support"
+ depends on X86_64 && CPU_SUP_INTEL
+ depends on X86_X2APIC
+ help
+ Support running as a guest under Intel TDX. Without this support,
+ the guest kernel can not boot or run under TDX.
+ TDX includes memory encryption and integrity capabilities
+ which protect the confidentiality and integrity of guest
+ memory contents and CPU state. TDX guests are protected from
+ some attacks from the VMM.
+
endif #HYPERVISOR_GUEST
source "arch/x86/Kconfig.cpu"
diff --git a/arch/x86/coco/Makefile b/arch/x86/coco/Makefile
index c1ead00..c816acf 100644
--- a/arch/x86/coco/Makefile
+++ b/arch/x86/coco/Makefile
@@ -4,3 +4,5 @@ KASAN_SANITIZE_core.o := n
CFLAGS_core.o += -fno-stack-protector
obj-y += core.o
+
+obj-$(CONFIG_INTEL_TDX_GUEST) += tdx/
diff --git a/arch/x86/coco/tdx/Makefile b/arch/x86/coco/tdx/Makefile
new file mode 100644
index 0000000..c929d53
--- /dev/null
+++ b/arch/x86/coco/tdx/Makefile
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0
+
+obj-y += tdx.o
diff --git a/arch/x86/coco/tdx/tdx.c b/arch/x86/coco/tdx/tdx.c
new file mode 100644
index 0000000..9767447
--- /dev/null
+++ b/arch/x86/coco/tdx/tdx.c
@@ -0,0 +1,22 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (C) 2021-2022 Intel Corporation */
+
+#undef pr_fmt
+#define pr_fmt(fmt) "tdx: " fmt
+
+#include <linux/cpufeature.h>
+#include <asm/tdx.h>
+
+void __init tdx_early_init(void)
+{
+ u32 eax, sig[3];
+
+ cpuid_count(TDX_CPUID_LEAF_ID, 0, &eax, &sig[0], &sig[2], &sig[1]);
+
+ if (memcmp(TDX_IDENT, sig, sizeof(sig)))
+ return;
+
+ setup_force_cpu_cap(X86_FEATURE_TDX_GUEST);
+
+ pr_info("Guest detected\n");
+}
diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index 73e643a..20df73b 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) /* Intel Trust 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/disabled-features.h b/arch/x86/include/asm/disabled-features.h
index 1231d63..b37de82 100644
--- a/arch/x86/include/asm/disabled-features.h
+++ b/arch/x86/include/asm/disabled-features.h
@@ -68,6 +68,12 @@
# define DISABLE_SGX (1 << (X86_FEATURE_SGX & 31))
#endif
+#ifdef CONFIG_INTEL_TDX_GUEST
+# define DISABLE_TDX_GUEST 0
+#else
+# define DISABLE_TDX_GUEST (1 << (X86_FEATURE_TDX_GUEST & 31))
+#endif
+
/*
* Make sure to add features to the correct mask
*/
@@ -79,7 +85,7 @@
#define DISABLED_MASK5 0
#define DISABLED_MASK6 0
#define DISABLED_MASK7 (DISABLE_PTI)
-#define DISABLED_MASK8 0
+#define DISABLED_MASK8 (DISABLE_TDX_GUEST)
#define DISABLED_MASK9 (DISABLE_SMAP|DISABLE_SGX)
#define DISABLED_MASK10 0
#define DISABLED_MASK11 0
diff --git a/arch/x86/include/asm/tdx.h b/arch/x86/include/asm/tdx.h
new file mode 100644
index 0000000..ba8042c
--- /dev/null
+++ b/arch/x86/include/asm/tdx.h
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (C) 2021-2022 Intel Corporation */
+#ifndef _ASM_X86_TDX_H
+#define _ASM_X86_TDX_H
+
+#include <linux/init.h>
+
+#define TDX_CPUID_LEAF_ID 0x21
+#define TDX_IDENT "IntelTDX "
+
+#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/head64.c b/arch/x86/kernel/head64.c
index 4f5ecbb..6dff50c 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.
@@ -514,6 +515,9 @@ asmlinkage __visible void __init x86_64_start_kernel(char * real_mode_data)
idt_setup_early_handler();
+ /* Needed before cc_platform_has() can be used for TDX */
+ tdx_early_init();
+
copy_bootdata(__va(real_mode_data));
/*
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