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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/mm | |
| 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/mm')
| -rw-r--r-- | arch/x86/mm/mem_encrypt_identity.c | 3 | ||||
| -rw-r--r-- | arch/x86/mm/pgtable.c | 5 |
2 files changed, 8 insertions, 0 deletions
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 <asm/fixmap.h> #include <asm/mtrr.h> +#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 |