Commit f88a68fa authored by Tom Lendacky's avatar Tom Lendacky Committed by Ingo Molnar
Browse files

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: default avatarTom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
Reviewed-by: default avatarBorislav Petkov <bp@suse.de>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Larry Woodman <lwoodman@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Toshimitsu Kani <toshi.kani@hpe.com>
Cc: kasan-dev@googlegroups.com
Cc: kvm@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Cc: linux-doc@vger.kernel.org
Cc: linux-efi@vger.kernel.org
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/479b5832c30fae3efa7932e48f81794e86397229.1500319216.git.thomas.lendacky@amd.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent eef9c4ab

arch/x86/Kconfig

+4 −0
Original line number Diff line number Diff line
@@ -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"

arch/x86/include/asm/fixmap.h

+13 −0
Original line number Diff line number Diff line
@@ -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)

arch/x86/include/asm/pgtable_types.h

+8 −0
Original line number Diff line number Diff line
@@ -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)

arch/x86/mm/ioremap.c

+44 −0
Original line number Diff line number Diff line
@@ -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)

include/asm-generic/early_ioremap.h

+2 −0
Original line number Diff line number Diff line
@@ -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);

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