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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/boot | |
| 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/boot')
| -rw-r--r-- | arch/x86/boot/compressed/kaslr_64.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/arch/x86/boot/compressed/kaslr_64.c b/arch/x86/boot/compressed/kaslr_64.c index 522d11431433..748456c365f4 100644 --- a/arch/x86/boot/compressed/kaslr_64.c +++ b/arch/x86/boot/compressed/kaslr_64.c @@ -69,6 +69,8 @@ static struct alloc_pgt_data pgt_data; /* The top level page table entry pointer. */ static unsigned long top_level_pgt; +phys_addr_t physical_mask = (1ULL << __PHYSICAL_MASK_SHIFT) - 1; + /* * Mapping information structure passed to kernel_ident_mapping_init(). * Due to relocation, pointers must be assigned at run time not build time. @@ -81,6 +83,9 @@ void initialize_identity_maps(void) /* If running as an SEV guest, the encryption mask is required. */ set_sev_encryption_mask(); + /* Exclude the encryption mask from __PHYSICAL_MASK */ + physical_mask &= ~sme_me_mask; + /* Init mapping_info with run-time function/buffer pointers. */ mapping_info.alloc_pgt_page = alloc_pgt_page; mapping_info.context = &pgt_data; |