[PATCH v3 3/8] x86/sev: Add an x86 version of cc_platform_has()
From: Tom Lendacky <thomas.lendacky@amd.com>
Date: 2021-09-08 22:59:23
Also in:
amd-gfx, dri-devel, kexec, kvm, linux-efi, linux-fsdevel, linux-iommu, linux-s390, lkml, platform-driver-x86
Subsystem:
the rest, x86 architecture (32-bit and 64-bit), x86 mm · Maintainers:
Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen, Andy Lutomirski, Peter Zijlstra
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. Cc: Thomas Gleixner <redacted> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Co-developed-by: Andi Kleen <redacted> Signed-off-by: Andi Kleen <redacted> Co-developed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> --- arch/x86/Kconfig | 1 + arch/x86/include/asm/mem_encrypt.h | 3 +++ arch/x86/kernel/Makefile | 3 +++ arch/x86/kernel/cc_platform.c | 21 +++++++++++++++++++++ arch/x86/mm/mem_encrypt.c | 21 +++++++++++++++++++++ 5 files changed, 49 insertions(+) create mode 100644 arch/x86/kernel/cc_platform.c
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 4e001bbbb425..2b2a9639d8ae 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig@@ -1513,6 +1513,7 @@ 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..3d8a5e8b2e3f 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>
@@ -53,6 +54,7 @@ void __init sev_es_init_vc_handling(void); bool sme_active(void); bool sev_active(void); bool sev_es_active(void); +bool amd_cc_platform_has(enum cc_attr attr); #define __bss_decrypted __section(".bss..decrypted")
@@ -78,6 +80,7 @@ static inline void sev_es_init_vc_handling(void) { } static inline bool sme_active(void) { return false; } static inline bool sev_active(void) { return false; } static inline bool sev_es_active(void) { return false; } +static inline bool amd_cc_platform_has(enum cc_attr attr) { return false; } static inline int __init early_set_memory_decrypted(unsigned long vaddr, unsigned long size) { return 0; }
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 8f4e8fa6ed75..f91403a78594 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile@@ -147,6 +147,9 @@ 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..3c9bacd3c3f3
--- /dev/null
+++ b/arch/x86/kernel/cc_platform.c@@ -0,0 +1,21 @@ +// 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> + +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..18fe19916bc3 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>
@@ -389,6 +390,26 @@ bool noinstr sev_es_active(void) return sev_status & MSR_AMD64_SEV_ES_ENABLED; } +bool amd_cc_platform_has(enum cc_attr attr) +{ + switch (attr) { + case CC_ATTR_MEM_ENCRYPT: + return sme_me_mask != 0; + + case CC_ATTR_HOST_MEM_ENCRYPT: + return sme_active(); + + case CC_ATTR_GUEST_MEM_ENCRYPT: + return sev_active(); + + case CC_ATTR_GUEST_STATE_ENCRYPT: + return sev_es_active(); + + default: + return false; + } +} + /* Override for DMA direct allocation check - ARCH_HAS_FORCE_DMA_UNENCRYPTED */ bool force_dma_unencrypted(struct device *dev) {
--
2.33.0