diff options
| -rw-r--r-- | arch/x86/include/asm/mem_encrypt.h | 10 | ||||
| -rw-r--r-- | arch/x86/mm/mem_encrypt.c | 76 |
2 files changed, 86 insertions, 0 deletions
diff --git a/arch/x86/include/asm/mem_encrypt.h b/arch/x86/include/asm/mem_encrypt.h index dbae7a5a347d..8baa35ba2316 100644 --- a/arch/x86/include/asm/mem_encrypt.h +++ b/arch/x86/include/asm/mem_encrypt.h @@ -21,6 +21,11 @@ extern unsigned long sme_me_mask; +void __init sme_early_encrypt(resource_size_t paddr, + unsigned long size); +void __init sme_early_decrypt(resource_size_t paddr, + unsigned long size); + void __init sme_early_init(void); void __init sme_encrypt_kernel(void); @@ -30,6 +35,11 @@ void __init sme_enable(void); #define sme_me_mask 0UL +static inline void __init sme_early_encrypt(resource_size_t paddr, + unsigned long size) { } +static inline void __init sme_early_decrypt(resource_size_t paddr, + unsigned long size) { } + static inline void __init sme_early_init(void) { } static inline void __init sme_encrypt_kernel(void) { } diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c index f973d3dc3802..54bb73c3dd9d 100644 --- a/arch/x86/mm/mem_encrypt.c +++ b/arch/x86/mm/mem_encrypt.c @@ -14,6 +14,9 @@ #include <linux/init.h> #include <linux/mm.h> +#include <asm/tlbflush.h> +#include <asm/fixmap.h> + /* * Since SME related variables are set early in the boot process they must * reside in the .data section so as not to be zeroed out when the .bss @@ -22,6 +25,79 @@ unsigned long sme_me_mask __section(.data) = 0; EXPORT_SYMBOL_GPL(sme_me_mask); +/* Buffer used for early in-place encryption by BSP, no locking needed */ +static char sme_early_buffer[PAGE_SIZE] __aligned(PAGE_SIZE); + +/* + * This routine does not change the underlying encryption setting of the + * page(s) that map this memory. It assumes that eventually the memory is + * meant to be accessed as either encrypted or decrypted but the contents + * are currently not in the desired state. + * + * This routine follows the steps outlined in the AMD64 Architecture + * Programmer's Manual Volume 2, Section 7.10.8 Encrypt-in-Place. + */ +static void __init __sme_early_enc_dec(resource_size_t paddr, + unsigned long size, bool enc) +{ + void *src, *dst; + size_t len; + + if (!sme_me_mask) + return; + + local_flush_tlb(); + wbinvd(); + + /* + * There are limited number of early mapping slots, so map (at most) + * one page at time. + */ + while (size) { + len = min_t(size_t, sizeof(sme_early_buffer), size); + + /* + * Create mappings for the current and desired format of + * the memory. Use a write-protected mapping for the source. + */ + src = enc ? early_memremap_decrypted_wp(paddr, len) : + early_memremap_encrypted_wp(paddr, len); + + dst = enc ? early_memremap_encrypted(paddr, len) : + early_memremap_decrypted(paddr, len); + + /* + * If a mapping can't be obtained to perform the operation, + * then eventual access of that area in the desired mode + * will cause a crash. + */ + BUG_ON(!src || !dst); + + /* + * Use a temporary buffer, of cache-line multiple size, to + * avoid data corruption as documented in the APM. + */ + memcpy(sme_early_buffer, src, len); + memcpy(dst, sme_early_buffer, len); + + early_memunmap(dst, len); + early_memunmap(src, len); + + paddr += len; + size -= len; + } +} + +void __init sme_early_encrypt(resource_size_t paddr, unsigned long size) +{ + __sme_early_enc_dec(paddr, size, true); +} + +void __init sme_early_decrypt(resource_size_t paddr, unsigned long size) +{ + __sme_early_enc_dec(paddr, size, false); +} + void __init sme_early_init(void) { unsigned int i; |