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Message-Id: <20210928191009.32551-3-bp@alien8.de>
Date: Tue, 28 Sep 2021 21:10:03 +0200
From: Borislav Petkov <bp@...en8.de>
To: LKML <linux-kernel@...r.kernel.org>
Cc: Andi Kleen <ak@...ux.intel.com>,
Kuppuswamy Sathyanarayanan
<sathyanarayanan.kuppuswamy@...ux.intel.com>,
Andy Lutomirski <luto@...nel.org>,
Ard Biesheuvel <ardb@...nel.org>, Baoquan He <bhe@...hat.com>,
Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Christian Borntraeger <borntraeger@...ibm.com>,
Daniel Vetter <daniel@...ll.ch>,
Dave Young <dyoung@...hat.com>,
David Airlie <airlied@...ux.ie>,
Heiko Carstens <hca@...ux.ibm.com>,
Joerg Roedel <joro@...tes.org>,
"Kirill A. Shutemov" <kirill@...temov.name>,
Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
Maxime Ripard <mripard@...nel.org>,
Michael Ellerman <mpe@...erman.id.au>,
Paul Mackerras <paulus@...ba.org>,
Tom Lendacky <thomas.lendacky@....com>,
Thomas Zimmermann <tzimmermann@...e.de>,
Vasily Gorbik <gor@...ux.ibm.com>,
VMware Graphics <linux-graphics-maintainer@...are.com>,
Will Deacon <will@...nel.org>,
Christoph Hellwig <hch@...radead.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,
amd-gfx@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org,
kexec@...ts.infradead.org
Subject: [PATCH 2/8] arch/cc: Introduce a function to check for confidential computing features
From: Tom Lendacky <thomas.lendacky@....com>
In preparation 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() || ... ).
[ bp: s/_CC_PLATFORM_H/_LINUX_CC_PLATFORM_H/g ]
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>
Signed-off-by: Borislav Petkov <bp@...e.de>
---
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 8df1c7102643..d1e69d6e8498 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..a075b70b9a70
--- /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 _LINUX_CC_PLATFORM_H
+#define _LINUX_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 /* _LINUX_CC_PLATFORM_H */
--
2.29.2
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