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Message-ID: <0a7618d54e7e954ee56c22ad1b94af2ffe69543a.1631141919.git.thomas.lendacky@amd.com>
Date: Wed, 8 Sep 2021 17:58:33 -0500
From: Tom Lendacky <thomas.lendacky@....com>
To: <linux-kernel@...r.kernel.org>, <x86@...nel.org>,
<linuxppc-dev@...ts.ozlabs.org>, <linux-s390@...r.kernel.org>,
<iommu@...ts.linux-foundation.org>, <kvm@...r.kernel.org>,
<linux-efi@...r.kernel.org>, <platform-driver-x86@...r.kernel.org>,
<linux-graphics-maintainer@...are.com>,
<amd-gfx@...ts.freedesktop.org>, <dri-devel@...ts.freedesktop.org>,
<kexec@...ts.infradead.org>, <linux-fsdevel@...r.kernel.org>
CC: Borislav Petkov <bp@...en8.de>,
Brijesh Singh <brijesh.singh@....com>,
Joerg Roedel <joro@...tes.org>,
Andi Kleen <ak@...ux.intel.com>,
Sathyanarayanan Kuppuswamy
<sathyanarayanan.kuppuswamy@...ux.intel.com>,
Tianyu Lan <Tianyu.Lan@...rosoft.com>,
Christoph Hellwig <hch@...radead.org>
Subject: [PATCH v3 2/8] mm: Introduce a function to check for confidential computing features
In prep for other confidential computing technologies, introduce a generic
helper function, cc_platform_has(), that can be used to check for specific
active confidential computing attributes, like memory encryption. This is
intended to eliminate having to add multiple technology-specific checks to
the code (e.g. if (sev_active() || tdx_active())).
Co-developed-by: Andi Kleen <ak@...ux.intel.com>
Signed-off-by: Andi Kleen <ak@...ux.intel.com>
Co-developed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@...ux.intel.com>
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@...ux.intel.com>
Signed-off-by: Tom Lendacky <thomas.lendacky@....com>
---
arch/Kconfig | 3 ++
include/linux/cc_platform.h | 88 +++++++++++++++++++++++++++++++++++++
2 files changed, 91 insertions(+)
create mode 100644 include/linux/cc_platform.h
diff --git a/arch/Kconfig b/arch/Kconfig
index 3743174da870..ca7c359e5da8 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -1234,6 +1234,9 @@ config RELR
config ARCH_HAS_MEM_ENCRYPT
bool
+config ARCH_HAS_CC_PLATFORM
+ bool
+
config HAVE_SPARSE_SYSCALL_NR
bool
help
diff --git a/include/linux/cc_platform.h b/include/linux/cc_platform.h
new file mode 100644
index 000000000000..253f3ea66cd8
--- /dev/null
+++ b/include/linux/cc_platform.h
@@ -0,0 +1,88 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Confidential Computing Platform Capability checks
+ *
+ * Copyright (C) 2021 Advanced Micro Devices, Inc.
+ *
+ * Author: Tom Lendacky <thomas.lendacky@....com>
+ */
+
+#ifndef _CC_PLATFORM_H
+#define _CC_PLATFORM_H
+
+#include <linux/types.h>
+#include <linux/stddef.h>
+
+/**
+ * enum cc_attr - Confidential computing attributes
+ *
+ * These attributes represent confidential computing features that are
+ * currently active.
+ */
+enum cc_attr {
+ /**
+ * @CC_ATTR_MEM_ENCRYPT: Memory encryption is active
+ *
+ * The platform/OS is running with active memory encryption. This
+ * includes running either as a bare-metal system or a hypervisor
+ * and actively using memory encryption or as a guest/virtual machine
+ * and actively using memory encryption.
+ *
+ * Examples include SME, SEV and SEV-ES.
+ */
+ CC_ATTR_MEM_ENCRYPT,
+
+ /**
+ * @CC_ATTR_HOST_MEM_ENCRYPT: Host memory encryption is active
+ *
+ * The platform/OS is running as a bare-metal system or a hypervisor
+ * and actively using memory encryption.
+ *
+ * Examples include SME.
+ */
+ CC_ATTR_HOST_MEM_ENCRYPT,
+
+ /**
+ * @CC_ATTR_GUEST_MEM_ENCRYPT: Guest memory encryption is active
+ *
+ * The platform/OS is running as a guest/virtual machine and actively
+ * using memory encryption.
+ *
+ * Examples include SEV and SEV-ES.
+ */
+ CC_ATTR_GUEST_MEM_ENCRYPT,
+
+ /**
+ * @CC_ATTR_GUEST_STATE_ENCRYPT: Guest state encryption is active
+ *
+ * The platform/OS is running as a guest/virtual machine and actively
+ * using memory encryption and register state encryption.
+ *
+ * Examples include SEV-ES.
+ */
+ CC_ATTR_GUEST_STATE_ENCRYPT,
+};
+
+#ifdef CONFIG_ARCH_HAS_CC_PLATFORM
+
+/**
+ * cc_platform_has() - Checks if the specified cc_attr attribute is active
+ * @attr: Confidential computing attribute to check
+ *
+ * The cc_platform_has() function will return an indicator as to whether the
+ * specified Confidential Computing attribute is currently active.
+ *
+ * Context: Any context
+ * Return:
+ * * TRUE - Specified Confidential Computing attribute is active
+ * * FALSE - Specified Confidential Computing attribute is not active
+ */
+bool cc_platform_has(enum cc_attr attr);
+
+#else /* !CONFIG_ARCH_HAS_CC_PLATFORM */
+
+static inline bool cc_platform_has(enum cc_attr attr) { return false; }
+
+#endif /* CONFIG_ARCH_HAS_CC_PLATFORM */
+
+#endif /* _CC_PLATFORM_H */
--
2.33.0
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