[PATCH v3 04/11] x86: Introduce generic protected guest abstraction
From: Kuppuswamy Sathyanarayanan
<sathyanarayanan.kuppuswamy@linux.intel.com>
Date: 2021-06-18 22:58:45
Subsystem:
the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
Add a generic way to check if we run with an encrypted guest, without requiring x86 specific ifdefs. This can then be used in non architecture specific code. prot_guest_has() is used to check for protected guest feature flags. Originally-by: Andi Kleen [off-list ref] Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> --- Change since v1: * Introduced PR_GUEST_TDX and PR_GUEST_SEV vendor flags as per Boris suggestion. * Replaced is_tdx_guest() with if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) in prot_guest_has(). * Modified tdx_protected_guest_has() and sev_protected_guest_has() to support vendor flags. arch/Kconfig | 3 +++ arch/x86/Kconfig | 2 ++ arch/x86/include/asm/protected_guest.h | 20 +++++++++++++++++ arch/x86/include/asm/sev.h | 3 +++ arch/x86/include/asm/tdx.h | 4 ++++ arch/x86/kernel/sev.c | 17 +++++++++++++++ arch/x86/kernel/tdx.c | 17 +++++++++++++++ include/linux/protected_guest.h | 30 ++++++++++++++++++++++++++ 8 files changed, 96 insertions(+) create mode 100644 arch/x86/include/asm/protected_guest.h create mode 100644 include/linux/protected_guest.h
diff --git a/arch/Kconfig b/arch/Kconfig
index c45b770d3579..3c5bf55ee752 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig@@ -1011,6 +1011,9 @@ config HAVE_ARCH_NVRAM_OPS config ISA_BUS_API def_bool ISA +config ARCH_HAS_PROTECTED_GUEST + bool + # # ABI hall of shame #
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index ff79263aebd1..d506aae29dd9 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig@@ -883,6 +883,7 @@ config INTEL_TDX_GUEST select PARAVIRT_XL select X86_X2APIC select SECURITY_LOCKDOWN_LSM + select ARCH_HAS_PROTECTED_GUEST help Provide support for running in a trusted domain on Intel processors equipped with Trusted Domain eXtenstions. TDX is a new Intel
@@ -1539,6 +1540,7 @@ config AMD_MEM_ENCRYPT select ARCH_HAS_FORCE_DMA_UNENCRYPTED select INSTRUCTION_DECODER select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS + select ARCH_HAS_PROTECTED_GUEST 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/protected_guest.h b/arch/x86/include/asm/protected_guest.h
new file mode 100644
index 000000000000..d47668dee6c2
--- /dev/null
+++ b/arch/x86/include/asm/protected_guest.h@@ -0,0 +1,20 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* Copyright (C) 2020 Intel Corporation */ +#ifndef _ASM_PROTECTED_GUEST_H +#define _ASM_PROTECTED_GUEST_H 1 + +#include <asm/processor.h> +#include <asm/tdx.h> +#include <asm/sev.h> + +static inline bool prot_guest_has(unsigned long flag) +{ + if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) + return tdx_protected_guest_has(flag); + else if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD) + return sev_protected_guest_has(flag); + + return false; +} + +#endif /* _ASM_PROTECTED_GUEST_H */
diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
index fa5cd05d3b5b..e9b0b93a3157 100644
--- a/arch/x86/include/asm/sev.h
+++ b/arch/x86/include/asm/sev.h@@ -81,12 +81,15 @@ static __always_inline void sev_es_nmi_complete(void) __sev_es_nmi_complete(); } extern int __init sev_es_efi_map_ghcbs(pgd_t *pgd); +bool sev_protected_guest_has(unsigned long flag); + #else static inline void sev_es_ist_enter(struct pt_regs *regs) { } static inline void sev_es_ist_exit(void) { } static inline int sev_es_setup_ap_jump_table(struct real_mode_header *rmh) { return 0; } static inline void sev_es_nmi_complete(void) { } static inline int sev_es_efi_map_ghcbs(pgd_t *pgd) { return 0; } +static inline bool sev_protected_guest_has(unsigned long flag) { return false; } #endif #endif
diff --git a/arch/x86/include/asm/tdx.h b/arch/x86/include/asm/tdx.h
index c738bde944d1..1c17c9080a2c 100644
--- a/arch/x86/include/asm/tdx.h
+++ b/arch/x86/include/asm/tdx.h@@ -11,10 +11,14 @@ void __init tdx_early_init(void); +bool tdx_protected_guest_has(unsigned long flag); + #else static inline void tdx_early_init(void) { }; +static inline bool tdx_protected_guest_has(unsigned long flag) { return false; } + #endif /* CONFIG_INTEL_TDX_GUEST */ #endif /* _ASM_X86_TDX_H */
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index 651b81cd648e..3e88576555d2 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c@@ -19,6 +19,7 @@ #include <linux/memblock.h> #include <linux/kernel.h> #include <linux/mm.h> +#include <linux/protected_guest.h> #include <asm/cpu_entry_area.h> #include <asm/stacktrace.h>
@@ -1493,3 +1494,19 @@ bool __init handle_vc_boot_ghcb(struct pt_regs *regs) while (true) halt(); } + +bool sev_protected_guest_has(unsigned long flag) +{ + switch (flag) { + case PR_GUEST_MEM_ENCRYPT: + case PR_GUEST_MEM_ENCRYPT_ACTIVE: + case PR_GUEST_UNROLL_STRING_IO: + case PR_GUEST_HOST_MEM_ENCRYPT: + return true; + case PR_GUEST_SEV: + return sev_active(); + } + + return false; +} +EXPORT_SYMBOL_GPL(sev_protected_guest_has);
diff --git a/arch/x86/kernel/tdx.c b/arch/x86/kernel/tdx.c
index b1492e076168..ae3334a2b29d 100644
--- a/arch/x86/kernel/tdx.c
+++ b/arch/x86/kernel/tdx.c@@ -4,6 +4,8 @@ #undef pr_fmt #define pr_fmt(fmt) "x86/tdx: " fmt +#include <linux/protected_guest.h> + #include <asm/tdx.h> static inline bool cpuid_has_tdx_guest(void)
@@ -18,6 +20,21 @@ static inline bool cpuid_has_tdx_guest(void) return !memcmp("IntelTDX ", sig, 12); } +bool tdx_protected_guest_has(unsigned long flag) +{ + switch (flag) { + case PR_GUEST_MEM_ENCRYPT: + case PR_GUEST_MEM_ENCRYPT_ACTIVE: + case PR_GUEST_UNROLL_STRING_IO: + case PR_GUEST_SHARED_MAPPING_INIT: + case PR_GUEST_TDX: + return static_cpu_has(X86_FEATURE_TDX_GUEST); + } + + return false; +} +EXPORT_SYMBOL_GPL(tdx_protected_guest_has); + void __init tdx_early_init(void) { if (!cpuid_has_tdx_guest())
diff --git a/include/linux/protected_guest.h b/include/linux/protected_guest.h
new file mode 100644
index 000000000000..c5b7547e5a68
--- /dev/null
+++ b/include/linux/protected_guest.h@@ -0,0 +1,30 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +#ifndef _LINUX_PROTECTED_GUEST_H +#define _LINUX_PROTECTED_GUEST_H 1 + +/* Protected Guest Feature Flags (leave 0-0xfff for vendor specific flags) */ + +/* 0-ff is reserved for Intel specific flags */ +#define PR_GUEST_TDX 0x0000 + +/* 100-1ff is reserved for AMD specific flags */ +#define PR_GUEST_SEV 0x0100 + +/* Support for guest encryption */ +#define PR_GUEST_MEM_ENCRYPT 0x1000 +/* Encryption support is active */ +#define PR_GUEST_MEM_ENCRYPT_ACTIVE 0x1001 +/* Support for unrolled string IO */ +#define PR_GUEST_UNROLL_STRING_IO 0x1002 +/* Support for host memory encryption */ +#define PR_GUEST_HOST_MEM_ENCRYPT 0x1003 +/* Support for shared mapping initialization (after early init) */ +#define PR_GUEST_SHARED_MAPPING_INIT 0x1004 + +#ifdef CONFIG_ARCH_HAS_PROTECTED_GUEST +#include <asm/protected_guest.h> +#else +static inline bool prot_guest_has(unsigned long flag) { return false; } +#endif + +#endif /* _LINUX_PROTECTED_GUEST_H */
--
2.25.1