[tip:x86/mm] x86/mm: Extend early_memremap() support with additional attrs

From: tip-bot for Tom Lendacky
Date: Tue Jul 18 2017 - 07:00:35 EST

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Commit-ID: f88a68facd9a15b94f8c195d9d2c0b30c76c595a
Gitweb: http://git.kernel.org/tip/f88a68facd9a15b94f8c195d9d2c0b30c76c595a
Author: Tom Lendacky <thomas.lendacky@xxxxxxx>
AuthorDate: Mon, 17 Jul 2017 16:10:09 -0500
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Tue, 18 Jul 2017 11:38:00 +0200

x86/mm: Extend early_memremap() support with additional attrs

Add early_memremap() support to be able to specify encrypted and
decrypted mappings with and without write-protection. The use of
write-protection is necessary when encrypting data "in place". The
write-protect attribute is considered cacheable for loads, but not
stores. This implies that the hardware will never give the core a
dirty line with this memtype.

Signed-off-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Reviewed-by: Borislav Petkov <bp@xxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Brijesh Singh <brijesh.singh@xxxxxxx>
Cc: Dave Young <dyoung@xxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Jonathan Corbet <corbet@xxxxxxx>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Cc: Larry Woodman <lwoodman@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Matt Fleming <matt@xxxxxxxxxxxxxxxxxxx>
Cc: Michael S. Tsirkin <mst@xxxxxxxxxx>
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Radim KrÄmÃÅ <rkrcmar@xxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Toshimitsu Kani <toshi.kani@xxxxxxx>
Cc: kasan-dev@xxxxxxxxxxxxxxxx
Cc: kvm@xxxxxxxxxxxxxxx
Cc: linux-arch@xxxxxxxxxxxxxxx
Cc: linux-doc@xxxxxxxxxxxxxxx
Cc: linux-efi@xxxxxxxxxxxxxxx
Cc: linux-mm@xxxxxxxxx
Link: http://lkml.kernel.org/r/479b5832c30fae3efa7932e48f81794e86397229.1500319216.git.thomas.lendacky@xxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/Kconfig | 4 ++++
arch/x86/include/asm/fixmap.h | 13 +++++++++++
arch/x86/include/asm/pgtable_types.h | 8 +++++++
arch/x86/mm/ioremap.c | 44 ++++++++++++++++++++++++++++++++++++
include/asm-generic/early_ioremap.h | 2 ++
mm/early_ioremap.c | 10 ++++++++
6 files changed, 81 insertions(+)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index ba7b93d..8328bcb 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1440,6 +1440,10 @@ config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
If set to N, then the encryption of system memory can be
activated with the mem_encrypt=on command line option.

+config ARCH_USE_MEMREMAP_PROT
+ def_bool y
+ depends on AMD_MEM_ENCRYPT
+
# Common NUMA Features
config NUMA
bool "Numa Memory Allocation and Scheduler Support"
diff --git a/arch/x86/include/asm/fixmap.h b/arch/x86/include/asm/fixmap.h
index d9ff226..dcd9fb5 100644
--- a/arch/x86/include/asm/fixmap.h
+++ b/arch/x86/include/asm/fixmap.h
@@ -164,6 +164,19 @@ static inline void __set_fixmap(enum fixed_addresses idx,
*/
#define FIXMAP_PAGE_NOCACHE PAGE_KERNEL_IO_NOCACHE

+/*
+ * Early memremap routines used for in-place encryption. The mappings created
+ * by these routines are intended to be used as temporary mappings.
+ */
+void __init *early_memremap_encrypted(resource_size_t phys_addr,
+ unsigned long size);
+void __init *early_memremap_encrypted_wp(resource_size_t phys_addr,
+ unsigned long size);
+void __init *early_memremap_decrypted(resource_size_t phys_addr,
+ unsigned long size);
+void __init *early_memremap_decrypted_wp(resource_size_t phys_addr,
+ unsigned long size);
+
#include <asm-generic/fixmap.h>

#define __late_set_fixmap(idx, phys, flags) __set_fixmap(idx, phys, flags)
diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h
index de32ca3..32095af 100644
--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -161,6 +161,7 @@ enum page_cache_mode {

#define _PAGE_CACHE_MASK (_PAGE_PAT | _PAGE_PCD | _PAGE_PWT)
#define _PAGE_NOCACHE (cachemode2protval(_PAGE_CACHE_MODE_UC))
+#define _PAGE_CACHE_WP (cachemode2protval(_PAGE_CACHE_MODE_WP))

#define PAGE_NONE __pgprot(_PAGE_PROTNONE | _PAGE_ACCESSED)
#define PAGE_SHARED __pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_USER | \
@@ -189,6 +190,7 @@ enum page_cache_mode {
#define __PAGE_KERNEL_VVAR (__PAGE_KERNEL_RO | _PAGE_USER)
#define __PAGE_KERNEL_LARGE (__PAGE_KERNEL | _PAGE_PSE)
#define __PAGE_KERNEL_LARGE_EXEC (__PAGE_KERNEL_EXEC | _PAGE_PSE)
+#define __PAGE_KERNEL_WP (__PAGE_KERNEL | _PAGE_CACHE_WP)

#define __PAGE_KERNEL_IO (__PAGE_KERNEL)
#define __PAGE_KERNEL_IO_NOCACHE (__PAGE_KERNEL_NOCACHE)
@@ -202,6 +204,12 @@ enum page_cache_mode {
#define _KERNPG_TABLE (_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED | \
_PAGE_DIRTY | _PAGE_ENC)

+#define __PAGE_KERNEL_ENC (__PAGE_KERNEL | _PAGE_ENC)
+#define __PAGE_KERNEL_ENC_WP (__PAGE_KERNEL_WP | _PAGE_ENC)
+
+#define __PAGE_KERNEL_NOENC (__PAGE_KERNEL)
+#define __PAGE_KERNEL_NOENC_WP (__PAGE_KERNEL_WP)
+
#define PAGE_KERNEL __pgprot(__PAGE_KERNEL | _PAGE_ENC)
#define PAGE_KERNEL_RO __pgprot(__PAGE_KERNEL_RO | _PAGE_ENC)
#define PAGE_KERNEL_EXEC __pgprot(__PAGE_KERNEL_EXEC | _PAGE_ENC)
diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index 66ddf5e..570201b 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -417,6 +417,50 @@ void unxlate_dev_mem_ptr(phys_addr_t phys, void *addr)
iounmap((void __iomem *)((unsigned long)addr & PAGE_MASK));
}

+#ifdef CONFIG_ARCH_USE_MEMREMAP_PROT
+/* Remap memory with encryption */
+void __init *early_memremap_encrypted(resource_size_t phys_addr,
+ unsigned long size)
+{
+ return early_memremap_prot(phys_addr, size, __PAGE_KERNEL_ENC);
+}
+
+/*
+ * Remap memory with encryption and write-protected - cannot be called
+ * before pat_init() is called
+ */
+void __init *early_memremap_encrypted_wp(resource_size_t phys_addr,
+ unsigned long size)
+{
+ /* Be sure the write-protect PAT entry is set for write-protect */
+ if (__pte2cachemode_tbl[_PAGE_CACHE_MODE_WP] != _PAGE_CACHE_MODE_WP)
+ return NULL;
+
+ return early_memremap_prot(phys_addr, size, __PAGE_KERNEL_ENC_WP);
+}
+
+/* Remap memory without encryption */
+void __init *early_memremap_decrypted(resource_size_t phys_addr,
+ unsigned long size)
+{
+ return early_memremap_prot(phys_addr, size, __PAGE_KERNEL_NOENC);
+}
+
+/*
+ * Remap memory without encryption and write-protected - cannot be called
+ * before pat_init() is called
+ */
+void __init *early_memremap_decrypted_wp(resource_size_t phys_addr,
+ unsigned long size)
+{
+ /* Be sure the write-protect PAT entry is set for write-protect */
+ if (__pte2cachemode_tbl[_PAGE_CACHE_MODE_WP] != _PAGE_CACHE_MODE_WP)
+ return NULL;
+
+ return early_memremap_prot(phys_addr, size, __PAGE_KERNEL_NOENC_WP);
+}
+#endif /* CONFIG_ARCH_USE_MEMREMAP_PROT */
+
static pte_t bm_pte[PAGE_SIZE/sizeof(pte_t)] __page_aligned_bss;

static inline pmd_t * __init early_ioremap_pmd(unsigned long addr)
diff --git a/include/asm-generic/early_ioremap.h b/include/asm-generic/early_ioremap.h
index 734ad4d..2edef8d 100644
--- a/include/asm-generic/early_ioremap.h
+++ b/include/asm-generic/early_ioremap.h
@@ -13,6 +13,8 @@ extern void *early_memremap(resource_size_t phys_addr,
unsigned long size);
extern void *early_memremap_ro(resource_size_t phys_addr,
unsigned long size);
+extern void *early_memremap_prot(resource_size_t phys_addr,
+ unsigned long size, unsigned long prot_val);
extern void early_iounmap(void __iomem *addr, unsigned long size);
extern void early_memunmap(void *addr, unsigned long size);

diff --git a/mm/early_ioremap.c b/mm/early_ioremap.c
index 6d5717b..d7d30da 100644
--- a/mm/early_ioremap.c
+++ b/mm/early_ioremap.c
@@ -226,6 +226,16 @@ early_memremap_ro(resource_size_t phys_addr, unsigned long size)
}
#endif

+#ifdef CONFIG_ARCH_USE_MEMREMAP_PROT
+void __init *
+early_memremap_prot(resource_size_t phys_addr, unsigned long size,
+ unsigned long prot_val)
+{
+ return (__force void *)__early_ioremap(phys_addr, size,
+ __pgprot(prot_val));
+}
+#endif
+
#define MAX_MAP_CHUNK (NR_FIX_BTMAPS << PAGE_SHIFT)

void __init copy_from_early_mem(void *dest, phys_addr_t src, unsigned long size)

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Previous message: tip-bot for Tom Lendacky: "[tip:x86/mm] x86/mm: Insure that boot memory areas are mapped properly"
In reply to: Tom Lendacky: "[PATCH v10 12/38] x86/mm: Extend early_memremap() support with additional attrs"
Next in thread: Tom Lendacky: "[PATCH v10 15/38] x86/boot/e820: Add support to determine the E820 type of an address"
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