Add support for changing the memory encryption attribute for one or more memory pages. Signed-off-by: Tom Lendacky <thomas.lendacky@xxxxxxx> --- arch/x86/include/asm/cacheflush.h | 3 ++ arch/x86/mm/pageattr.c | 66 +++++++++++++++++++++++++++++++++++++ 2 files changed, 69 insertions(+) diff --git a/arch/x86/include/asm/cacheflush.h b/arch/x86/include/asm/cacheflush.h index 872877d..33ae60a 100644 --- a/arch/x86/include/asm/cacheflush.h +++ b/arch/x86/include/asm/cacheflush.h @@ -12,6 +12,7 @@ * Executability : eXeutable, NoteXecutable * Read/Write : ReadOnly, ReadWrite * Presence : NotPresent + * Encryption : Encrypted, Decrypted * * Within a category, the attributes are mutually exclusive. * @@ -47,6 +48,8 @@ int set_memory_rw(unsigned long addr, int numpages); int set_memory_np(unsigned long addr, int numpages); int set_memory_4k(unsigned long addr, int numpages); +int set_memory_encrypted(unsigned long addr, int numpages); +int set_memory_decrypted(unsigned long addr, int numpages); int set_memory_array_uc(unsigned long *addr, int addrinarray); int set_memory_array_wc(unsigned long *addr, int addrinarray); diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index 91c5c63..9710f5c 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -1742,6 +1742,72 @@ int set_memory_4k(unsigned long addr, int numpages) __pgprot(0), 1, 0, NULL); } +static int __set_memory_enc_dec(unsigned long addr, int numpages, bool enc) +{ + struct cpa_data cpa; + unsigned long start; + int ret; + + /* Nothing to do if the _PAGE_ENC attribute is zero */ + if (_PAGE_ENC == 0) + return 0; + + /* Save original start address since it will be modified */ + start = addr; + + memset(&cpa, 0, sizeof(cpa)); + cpa.vaddr = &addr; + cpa.numpages = numpages; + cpa.mask_set = enc ? __pgprot(_PAGE_ENC) : __pgprot(0); + cpa.mask_clr = enc ? __pgprot(0) : __pgprot(_PAGE_ENC); + cpa.pgd = init_mm.pgd; + + /* Should not be working on unaligned addresses */ + if (WARN_ONCE(*cpa.vaddr & ~PAGE_MASK, + "misaligned address: %#lx\n", *cpa.vaddr)) + *cpa.vaddr &= PAGE_MASK; + + /* Must avoid aliasing mappings in the highmem code */ + kmap_flush_unused(); + vm_unmap_aliases(); + + /* + * Before changing the encryption attribute, we need to flush caches. + */ + if (static_cpu_has(X86_FEATURE_CLFLUSH)) + cpa_flush_range(start, numpages, 1); + else + cpa_flush_all(1); + + ret = __change_page_attr_set_clr(&cpa, 1); + + /* + * After changing the encryption attribute, we need to flush TLBs + * again in case any speculative TLB caching occurred (but no need + * to flush caches again). We could just use cpa_flush_all(), but + * in case TLB flushing gets optimized in the cpa_flush_range() + * path use the same logic as above. + */ + if (static_cpu_has(X86_FEATURE_CLFLUSH)) + cpa_flush_range(start, numpages, 0); + else + cpa_flush_all(0); + + return ret; +} + +int set_memory_encrypted(unsigned long addr, int numpages) +{ + return __set_memory_enc_dec(addr, numpages, true); +} +EXPORT_SYMBOL(set_memory_encrypted); + +int set_memory_decrypted(unsigned long addr, int numpages) +{ + return __set_memory_enc_dec(addr, numpages, false); +} +EXPORT_SYMBOL(set_memory_decrypted); + int set_pages_uc(struct page *page, int numpages) { unsigned long addr = (unsigned long)page_address(page); -- To unsubscribe from this list: send the line "unsubscribe linux-efi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html