From: Borislav Petkov <bp@alien8.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>,
Ard Biesheuvel <ardb@kernel.org>, Baoquan He <bhe@redhat.com>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Christian Borntraeger <borntraeger@de.ibm.com>,
Daniel Vetter <daniel@ffwll.ch>, Dave Young <dyoung@redhat.com>,
David Airlie <airlied@linux.ie>,
Heiko Carstens <hca@linux.ibm.com>,
Joerg Roedel <joro@8bytes.org>,
"Kirill A. Shutemov" <kirill@shutemov.name>,
"Kuppuswamy,
Sathyanarayanan" <sathyanarayanan.kuppuswamy@linux.intel.com>,
Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
Maxime Ripard <mripard@kernel.org>,
Michael Ellerman <mpe@ellerman.id.au>,
Paul Mackerras <paulus@samba.org>,
Tom Lendacky <thomas.lendacky@amd.com>,
Thomas Zimmermann <tzimmermann@suse.de>,
Vasily Gorbik <gor@linux.ibm.com>,
VMware Graphics <linux-graphics-maintainer@vmware.com>,
Will Deacon <will@kernel.org>,
Christoph Hellwig <hch@infradead.org>,
x86@kernel.org, linuxppc-dev@lists.ozlabs.org,
linux-s390@vger.kernel.org, iommu@lists.linux-foundation.org,
kvm@vger.kernel.org, linux-efi@vger.kernel.org,
platform-driver-x86@vger.kernel.org,
amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
kexec@lists.infradead.org
Subject: [PATCH 3/8] x86/sev: Add an x86 version of cc_platform_has()
Date: Tue, 28 Sep 2021 21:10:04 +0200 [thread overview]
Message-ID: <20210928191009.32551-4-bp@alien8.de> (raw)
In-Reply-To: <20210928191009.32551-1-bp@alien8.de>
From: Tom Lendacky <thomas.lendacky@amd.com>
Introduce an x86 version of the cc_platform_has() function. This will be
used to replace vendor specific calls like sme_active(), sev_active(),
etc.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
---
arch/x86/Kconfig | 1 +
arch/x86/include/asm/mem_encrypt.h | 1 +
arch/x86/kernel/Makefile | 6 +++
arch/x86/kernel/cc_platform.c | 69 ++++++++++++++++++++++++++++++
arch/x86/mm/mem_encrypt.c | 1 +
5 files changed, 78 insertions(+)
create mode 100644 arch/x86/kernel/cc_platform.c
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index ab83c22d274e..9f190ec4f953 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1518,6 +1518,7 @@ config AMD_MEM_ENCRYPT
select ARCH_HAS_FORCE_DMA_UNENCRYPTED
select INSTRUCTION_DECODER
select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS
+ select ARCH_HAS_CC_PLATFORM
help
Say yes to enable support for the encryption of system memory.
This requires an AMD processor that supports Secure Memory
diff --git a/arch/x86/include/asm/mem_encrypt.h b/arch/x86/include/asm/mem_encrypt.h
index 9c80c68d75b5..3fb9f5ebefa4 100644
--- a/arch/x86/include/asm/mem_encrypt.h
+++ b/arch/x86/include/asm/mem_encrypt.h
@@ -13,6 +13,7 @@
#ifndef __ASSEMBLY__
#include <linux/init.h>
+#include <linux/cc_platform.h>
#include <asm/bootparam.h>
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 8f4e8fa6ed75..2ff3e600f426 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -21,6 +21,7 @@ CFLAGS_REMOVE_ftrace.o = -pg
CFLAGS_REMOVE_early_printk.o = -pg
CFLAGS_REMOVE_head64.o = -pg
CFLAGS_REMOVE_sev.o = -pg
+CFLAGS_REMOVE_cc_platform.o = -pg
endif
KASAN_SANITIZE_head$(BITS).o := n
@@ -29,6 +30,7 @@ KASAN_SANITIZE_dumpstack_$(BITS).o := n
KASAN_SANITIZE_stacktrace.o := n
KASAN_SANITIZE_paravirt.o := n
KASAN_SANITIZE_sev.o := n
+KASAN_SANITIZE_cc_platform.o := n
# With some compiler versions the generated code results in boot hangs, caused
# by several compilation units. To be safe, disable all instrumentation.
@@ -47,6 +49,7 @@ endif
KCOV_INSTRUMENT := n
CFLAGS_head$(BITS).o += -fno-stack-protector
+CFLAGS_cc_platform.o += -fno-stack-protector
CFLAGS_irq.o := -I $(srctree)/$(src)/../include/asm/trace
@@ -147,6 +150,9 @@ obj-$(CONFIG_UNWINDER_FRAME_POINTER) += unwind_frame.o
obj-$(CONFIG_UNWINDER_GUESS) += unwind_guess.o
obj-$(CONFIG_AMD_MEM_ENCRYPT) += sev.o
+
+obj-$(CONFIG_ARCH_HAS_CC_PLATFORM) += cc_platform.o
+
###
# 64 bit specific files
ifeq ($(CONFIG_X86_64),y)
diff --git a/arch/x86/kernel/cc_platform.c b/arch/x86/kernel/cc_platform.c
new file mode 100644
index 000000000000..03bb2f343ddb
--- /dev/null
+++ b/arch/x86/kernel/cc_platform.c
@@ -0,0 +1,69 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Confidential Computing Platform Capability checks
+ *
+ * Copyright (C) 2021 Advanced Micro Devices, Inc.
+ *
+ * Author: Tom Lendacky <thomas.lendacky@amd.com>
+ */
+
+#include <linux/export.h>
+#include <linux/cc_platform.h>
+#include <linux/mem_encrypt.h>
+
+#include <asm/processor.h>
+
+static bool __maybe_unused intel_cc_platform_has(enum cc_attr attr)
+{
+#ifdef CONFIG_INTEL_TDX_GUEST
+ return false;
+#else
+ return false;
+#endif
+}
+
+/*
+ * SME and SEV are very similar but they are not the same, so there are
+ * times that the kernel will need to distinguish between SME and SEV. The
+ * cc_platform_has() function is used for this. When a distinction isn't
+ * needed, the CC_ATTR_MEM_ENCRYPT attribute can be used.
+ *
+ * The trampoline code is a good example for this requirement. Before
+ * paging is activated, SME will access all memory as decrypted, but SEV
+ * will access all memory as encrypted. So, when APs are being brought
+ * up under SME the trampoline area cannot be encrypted, whereas under SEV
+ * the trampoline area must be encrypted.
+ */
+static bool amd_cc_platform_has(enum cc_attr attr)
+{
+#ifdef CONFIG_AMD_MEM_ENCRYPT
+ switch (attr) {
+ case CC_ATTR_MEM_ENCRYPT:
+ return sme_me_mask;
+
+ case CC_ATTR_HOST_MEM_ENCRYPT:
+ return sme_me_mask && !(sev_status & MSR_AMD64_SEV_ENABLED);
+
+ case CC_ATTR_GUEST_MEM_ENCRYPT:
+ return sev_status & MSR_AMD64_SEV_ENABLED;
+
+ case CC_ATTR_GUEST_STATE_ENCRYPT:
+ return sev_status & MSR_AMD64_SEV_ES_ENABLED;
+
+ default:
+ return false;
+ }
+#else
+ return false;
+#endif
+}
+
+
+bool cc_platform_has(enum cc_attr attr)
+{
+ if (sme_me_mask)
+ return amd_cc_platform_has(attr);
+
+ return false;
+}
+EXPORT_SYMBOL_GPL(cc_platform_has);
diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index ff08dc463634..e29b1418d00c 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -20,6 +20,7 @@
#include <linux/bitops.h>
#include <linux/dma-mapping.h>
#include <linux/virtio_config.h>
+#include <linux/cc_platform.h>
#include <asm/tlbflush.h>
#include <asm/fixmap.h>
--
2.29.2
next prev parent reply other threads:[~2021-09-28 19:10 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-28 19:10 [PATCH v4 0/8] Implement generic cc_platform_has() helper function Borislav Petkov
2021-09-28 19:10 ` [PATCH 1/8] x86/ioremap: Selectively build arch override encryption functions Borislav Petkov
2021-09-28 19:10 ` [PATCH 2/8] arch/cc: Introduce a function to check for confidential computing features Borislav Petkov
2021-09-28 19:10 ` Borislav Petkov [this message]
2021-09-28 19:10 ` [PATCH 4/8] powerpc/pseries/svm: Add a powerpc version of cc_platform_has() Borislav Petkov
2021-09-28 19:10 ` [PATCH 5/8] x86/sme: Replace occurrences of sme_active() with cc_platform_has() Borislav Petkov
2021-09-28 19:10 ` [PATCH 6/8] x86/sev: Replace occurrences of sev_active() " Borislav Petkov
2021-09-28 19:10 ` [PATCH 7/8] x86/sev: Replace occurrences of sev_es_active() " Borislav Petkov
2021-09-28 19:10 ` [PATCH 8/8] treewide: Replace the use of mem_encrypt_active() " Borislav Petkov
2021-09-28 19:19 ` [PATCH v4 0/8] Implement generic cc_platform_has() helper function Kuppuswamy, Sathyanarayanan
2021-09-28 20:31 ` Borislav Petkov
2021-09-28 20:48 ` Kuppuswamy, Sathyanarayanan
2021-09-28 20:58 ` Borislav Petkov
2021-09-28 21:01 ` Kuppuswamy, Sathyanarayanan
2021-09-28 21:40 ` Borislav Petkov
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