From 94d49eb30e854c84d1319095b5dd0405a7da9362 Mon Sep 17 00:00:00 2001 From: "Kirill A. Shutemov" Date: Fri, 18 May 2018 14:30:28 +0300 Subject: 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 Signed-off-by: Thomas Gleixner Reviewed-by: Tom Lendacky Cc: linux-mm@kvack.org Cc: "H. Peter Anvin" Link: https://lkml.kernel.org/r/20180518113028.79825-1-kirill.shutemov@linux.intel.com --- arch/x86/boot/compressed/kaslr_64.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'arch/x86/boot') 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; -- cgit v1.2.3