Introduce an x86 version of the prot_guest_has() function. This will be
used in the more generic x86 code to replace vendor specific calls like
sev_active(), etc.
While the name suggests this is intended mainly for guests, it will
also be used for host memory encryption checks in place of sme_active().
The amd_prot_guest_has() function does not use EXPORT_SYMBOL_GPL for the
same reasons previously stated when changing sme_active(), sev_active and
sme_me_mask to EXPORT_SYBMOL:
commit 87df26175e67 ("x86/mm: Unbreak modules that rely on external
PAGE_KERNEL availability")
commit 9d5f38ba6c82 ("x86/mm: Unbreak modules that use the DMA API")
Cc: Thomas Gleixner
Cc: Ingo Molnar
Cc: Borislav Petkov
Cc: Dave Hansen
Cc: Andy Lutomirski
Cc: Peter Zijlstra
Co-developed-by: Andi Kleen
Signed-off-by: Andi Kleen
Co-developed-by: Kuppuswamy Sathyanarayanan
Signed-off-by: Kuppuswamy Sathyanarayanan
Signed-off-by: Tom Lendacky
---
arch/x86/Kconfig | 1 +
arch/x86/include/asm/mem_encrypt.h | 2 ++
arch/x86/include/asm/protected_guest.h | 27 ++
arch/x86/mm/mem_encrypt.c | 25
include/linux/protected_guest.h| 5 +
5 files changed, 60 insertions(+)
create mode 100644 arch/x86/include/asm/protected_guest.h
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 49270655e827..e47213cbfc55 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1514,6 +1514,7 @@ 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/mem_encrypt.h
b/arch/x86/include/asm/mem_encrypt.h
index 9c80c68d75b5..a46d47662772 100644
--- a/arch/x86/include/asm/mem_encrypt.h
+++ b/arch/x86/include/asm/mem_encrypt.h
@@ -53,6 +53,7 @@ void __init sev_es_init_vc_handling(void);
bool sme_active(void);
bool sev_active(void);
bool sev_es_active(void);
+bool amd_prot_guest_has(unsigned int attr);
#define __bss_decrypted __section(".bss..decrypted")
@@ -78,6 +79,7 @@ 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_prot_guest_has(unsigned int attr) { return false; }
static inline int __init
early_set_memory_decrypted(unsigned long vaddr, unsigned long size) { return
0; }
diff --git a/arch/x86/include/asm/protected_guest.h
b/arch/x86/include/asm/protected_guest.h
new file mode 100644
index ..b4a267dddf93
--- /dev/null
+++ b/arch/x86/include/asm/protected_guest.h
@@ -0,0 +1,27 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Protected Guest (and Host) Capability checks
+ *
+ * Copyright (C) 2021 Advanced Micro Devices, Inc.
+ *
+ * Author: Tom Lendacky
+ */
+
+#ifndef _X86_PROTECTED_GUEST_H
+#define _X86_PROTECTED_GUEST_H
+
+#include
+
+#ifndef __ASSEMBLY__
+
+static inline bool prot_guest_has(unsigned int attr)
+{
+ if (sme_me_mask)
+ return amd_prot_guest_has(attr);
+
+ return false;
+}
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* _X86_PROTECTED_GUEST_H */
diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index ff08dc463634..7d3b2c6f5f88 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -20,6 +20,7 @@
#include
#include
#include
+#include
#include
#include
@@ -389,6 +390,30 @@ bool noinstr sev_es_active(void)
return sev_status & MSR_AMD64_SEV_ES_ENABLED;
}
+bool amd_prot_guest_has(unsigned int attr)
+{
+ switch (attr) {
+ case PATTR_MEM_ENCRYPT:
+ return sme_me_mask != 0;
+
+ case PATTR_SME:
+ case PATTR_HOST_MEM_ENCRYPT:
+ return sme_active();
+
+ case PATTR_SEV:
+ case PATTR_GUEST_MEM_ENCRYPT:
+ return sev_active();
+
+ case PATTR_SEV_ES:
+ case PATTR_GUEST_PROT_STATE:
+ return sev_es_active();
+
+ default:
+ return false;
+ }
+}
+EXPORT_SYMBOL(amd_prot_guest_has);
+
/* Override for DMA direct allocation check - ARCH_HAS_FORCE_DMA_UNENCRYPTED */
bool force_dma_unencrypted(struct device *dev)
{
diff --git a/include/linux/protected_guest.h b/include/linux/protected_guest.h
index f8ed7b72967b..7a7120abbb62 100644
--- a/include/linux/protected_guest.h
+++ b/include/linux/protected_guest.h
@@ -17,6 +17,11 @@
#define PATTR_GUEST_MEM_ENCRYPT2 /* Guest encrypted
memory */
#define PATTR_GUEST_PROT_STATE 3 /* Guest encrypted state */
+/* 0x800 - 0x8ff reserved for AMD */
+#define PATTR_SME 0x800
+#define PATTR_SEV
