Re: [PATCH v7 10/36] x86/mm: Provide general kernel support for memory encryption

[Borislav Petkov]

On Wed, Jun 21, 2017 at 09:18:59AM +0200, Thomas Gleixner wrote:
> That looks wrong. It's not decrypted it's rather unencrypted, right?

Yeah, it previous versions of the patchset, "decrypted" and
"unencrypted" were both present so we settled on "decrypted" for the
nomenclature.

-- 
Regards/Gruss,
Boris.

Good mailing practices for 400: avoid top-posting and trim the reply.
--
To unsubscribe from this list: send the line "unsubscribe linux-efi" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: [PATCH v7 10/36] x86/mm: Provide general kernel support for memory encryption

[Thomas Gleixner]

On Fri, 16 Jun 2017, Tom Lendacky wrote:
>  
> +#ifndef pgprot_encrypted
> +#define pgprot_encrypted(prot)   (prot)
> +#endif
> +
> +#ifndef pgprot_decrypted

That looks wrong. It's not decrypted it's rather unencrypted, right?

Thanks,

tglx
--
To unsubscribe from this list: send the line "unsubscribe linux-efi" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[PATCH v7 10/36] x86/mm: Provide general kernel support for memory encryption

[Tom Lendacky]

Changes to the existing page table macros will allow the SME support to
be enabled in a simple fashion with minimal changes to files that use these
macros.  Since the memory encryption mask will now be part of the regular
pagetable macros, we introduce two new macros (_PAGE_TABLE_NOENC and
_KERNPG_TABLE_NOENC) to allow for early pagetable creation/initialization
without the encryption mask before SME becomes active.  Two new pgprot()
macros are defined to allow setting or clearing the page encryption mask.

The FIXMAP_PAGE_NOCACHE define is introduced for use with MMIO.  SME does
not support encryption for MMIO areas so this define removes the encryption
mask from the page attribute.

Two new macros are introduced (__sme_pa() / __sme_pa_nodebug()) to allow
creating a physical address with the encryption mask.  These are used when
working with the cr3 register so that the PGD can be encrypted. The current
__va() macro is updated so that the virtual address is generated based off
of the physical address without the encryption mask thus allowing the same
virtual address to be generated regardless of whether encryption is enabled
for that physical location or not.

Also, an early initialization function is added for SME.  If SME is active,
this function:
 - Updates the early_pmd_flags so that early page faults create mappings
   with the encryption mask.
 - Updates the __supported_pte_mask to include the encryption mask.
 - Updates the protection_map entries to include the encryption mask so
   that user-space allocations will automatically have the encryption mask
   applied.

Reviewed-by: Borislav Petkov 
Signed-off-by: Tom Lendacky 
---
 arch/x86/boot/compressed/pagetable.c |7 +
 arch/x86/include/asm/fixmap.h|7 +
 arch/x86/include/asm/mem_encrypt.h   |   13 ++
 arch/x86/include/asm/page_types.h|3 ++
 arch/x86/include/asm/pgtable.h   |9 +++
 arch/x86/include/asm/pgtable_types.h |   45 ++
 arch/x86/include/asm/processor.h |3 ++
 arch/x86/kernel/espfix_64.c  |2 +-
 arch/x86/kernel/head64.c |   11 +++-
 arch/x86/kernel/head_64.S|   20 ---
 arch/x86/mm/kasan_init_64.c  |4 ++-
 arch/x86/mm/mem_encrypt.c|   18 ++
 arch/x86/mm/pageattr.c   |3 ++
 include/asm-generic/pgtable.h|8 ++
 include/linux/mem_encrypt.h  |8 ++
 15 files changed, 128 insertions(+), 33 deletions(-)

diff --git a/arch/x86/boot/compressed/pagetable.c 
b/arch/x86/boot/compressed/pagetable.c
index 8e69df9..246bf29 100644
--- a/arch/x86/boot/compressed/pagetable.c
+++ b/arch/x86/boot/compressed/pagetable.c
@@ -15,6 +15,13 @@
 #define __pa(x)  ((unsigned long)(x))
 #define __va(x)  ((void *)((unsigned long)(x)))
 
+/*
+ * The pgtable.h and mm/ident_map.c includes make use of the SME related
+ * information which is not used in the compressed image support. Un-define
+ * the SME support to avoid any compile and link errors.
+ */
+#undef CONFIG_AMD_MEM_ENCRYPT
+
 #include "misc.h"
 
 /* These actually do the work of building the kernel identity maps. */
diff --git a/arch/x86/include/asm/fixmap.h b/arch/x86/include/asm/fixmap.h
index b65155c..d9ff226 100644
--- a/arch/x86/include/asm/fixmap.h
+++ b/arch/x86/include/asm/fixmap.h
@@ -157,6 +157,13 @@ static inline void __set_fixmap(enum fixed_addresses idx,
 }
 #endif
 
+/*
+ * FIXMAP_PAGE_NOCACHE is used for MMIO. Memory encryption is not
+ * supported for MMIO addresses, so make sure that the memory encryption
+ * mask is not part of the page attributes.
+ */
+#define FIXMAP_PAGE_NOCACHE PAGE_KERNEL_IO_NOCACHE
+
 #include 
 
 #define __late_set_fixmap(idx, phys, flags) __set_fixmap(idx, phys, flags)
diff --git a/arch/x86/include/asm/mem_encrypt.h 
b/arch/x86/include/asm/mem_encrypt.h
index 988b336..faae4e1 100644
--- a/arch/x86/include/asm/mem_encrypt.h
+++ b/arch/x86/include/asm/mem_encrypt.h
@@ -21,18 +21,31 @@
 
 extern unsigned long sme_me_mask;
 
+void __init sme_early_init(void);
+
 void __init sme_enable(void);
 
 #else  /* !CONFIG_AMD_MEM_ENCRYPT */
 
 #define sme_me_mask0UL
 
+static inline void __init sme_early_init(void) { }
+
 static inline void __init sme_enable(void) { }
 
 #endif /* CONFIG_AMD_MEM_ENCRYPT */
 
 unsigned long sme_get_me_mask(void);
 
+/*
+ * The __sme_pa() and __sme_pa_nodebug() macros are meant for use when
+ * writing to or comparing values from the cr3 register.  Having the
+ * encryption mask set in cr3 enables the PGD entry to be encrypted and
+ * avoid special case handling of PGD allocations.
+ */
+#define __sme_pa(x)(__pa(x) | sme_me_mask)
+#define __sme_pa_nodebug(x)(__pa_nodebug(x) | sme_me_mask)
+
 #endif /* __ASSEMBLY__ */
 
 #endif /* __X86_MEM_ENCRYPT_H__ */
diff --git a/arch/x86/include/asm/page_types.h 
b/arch/x86/include/asm/page_types.h
index 7bd0099..b98ed9d 100644
---