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| author | Kirill A. Shutemov <kirill.shutemov@linux.intel.com> | 2018-05-18 13:30:28 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2018-06-06 13:38:01 +0200 |
| commit | 94d49eb30e854c84d1319095b5dd0405a7da9362 (patch) | |
| tree | 0c2c2a712fae357f64de8e330c4956bda1215255 /arch/x86/Kconfig | |
| parent | x86: Mark native_set_p4d() as __always_inline (diff) | |
| download | linux-94d49eb30e854c84d1319095b5dd0405a7da9362.tar.xz linux-94d49eb30e854c84d1319095b5dd0405a7da9362.zip | |
x86/mm: Decouple dynamic __PHYSICAL_MASK from AMD SME
AMD SME claims one bit from physical address to indicate whether the
page is encrypted or not. To achieve that we clear out the bit from
__PHYSICAL_MASK.
The capability to adjust __PHYSICAL_MASK is required beyond AMD SME.
For instance for upcoming Intel Multi-Key Total Memory Encryption.
Factor it out into a separate feature with own Kconfig handle.
It also helps with overhead of AMD SME. It saves more than 3k in .text
on defconfig + AMD_MEM_ENCRYPT:
add/remove: 3/2 grow/shrink: 5/110 up/down: 189/-3753 (-3564)
We would need to return to this once we have infrastructure to patch
constants in code. That's good candidate for it.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Cc: linux-mm@kvack.org
Cc: "H. Peter Anvin" <hpa@zytor.com>
Link: https://lkml.kernel.org/r/20180518113028.79825-1-kirill.shutemov@linux.intel.com
Diffstat (limited to 'arch/x86/Kconfig')
| -rw-r--r-- | arch/x86/Kconfig | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index c07f492b871a..43a8fc476296 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -337,6 +337,9 @@ config ARCH_SUPPORTS_UPROBES config FIX_EARLYCON_MEM def_bool y +config DYNAMIC_PHYSICAL_MASK + bool + config PGTABLE_LEVELS int default 5 if X86_5LEVEL @@ -1508,6 +1511,7 @@ config ARCH_HAS_MEM_ENCRYPT config AMD_MEM_ENCRYPT bool "AMD Secure Memory Encryption (SME) support" depends on X86_64 && CPU_SUP_AMD + select DYNAMIC_PHYSICAL_MASK ---help--- Say yes to enable support for the encryption of system memory. This requires an AMD processor that supports Secure Memory |