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/mm/mem_encrypt_identity.c | 3 +++ arch/x86/mm/pgtable.c | 5 +++++ 2 files changed, 8 insertions(+) (limited to 'arch/x86/mm') diff --git a/arch/x86/mm/mem_encrypt_identity.c b/arch/x86/mm/mem_encrypt_identity.c index 1b2197d13832..7ae36868aed2 100644 --- a/arch/x86/mm/mem_encrypt_identity.c +++ b/arch/x86/mm/mem_encrypt_identity.c @@ -527,6 +527,7 @@ void __init sme_enable(struct boot_params *bp) /* SEV state cannot be controlled by a command line option */ sme_me_mask = me_mask; sev_enabled = true; + physical_mask &= ~sme_me_mask; return; } @@ -561,4 +562,6 @@ void __init sme_enable(struct boot_params *bp) sme_me_mask = 0; else sme_me_mask = active_by_default ? me_mask : 0; + + physical_mask &= ~sme_me_mask; } diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c index ffc8c13c50e4..3ca59cf7a7f9 100644 --- a/arch/x86/mm/pgtable.c +++ b/arch/x86/mm/pgtable.c @@ -8,6 +8,11 @@ #include #include +#ifdef CONFIG_DYNAMIC_PHYSICAL_MASK +phys_addr_t physical_mask __ro_after_init = (1ULL << __PHYSICAL_MASK_SHIFT) - 1; +EXPORT_SYMBOL(physical_mask); +#endif + #define PGALLOC_GFP (GFP_KERNEL_ACCOUNT | __GFP_ZERO) #ifdef CONFIG_HIGHPTE -- cgit v1.2.3