diff options
Diffstat (limited to 'arch/x86/mm')
| -rw-r--r-- | arch/x86/mm/mem_encrypt.c | 130 |
1 files changed, 130 insertions, 0 deletions
diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c index d29b7831a053..5049b8bad3e7 100644 --- a/arch/x86/mm/mem_encrypt.c +++ b/arch/x86/mm/mem_encrypt.c @@ -30,6 +30,8 @@ #include <asm/msr.h> #include <asm/cmdline.h> +#include "mm_internal.h" + static char sme_cmdline_arg[] __initdata = "mem_encrypt"; static char sme_cmdline_on[] __initdata = "on"; static char sme_cmdline_off[] __initdata = "off"; @@ -260,6 +262,134 @@ static void sev_free(struct device *dev, size_t size, void *vaddr, swiotlb_free_coherent(dev, size, vaddr, dma_handle); } +static void __init __set_clr_pte_enc(pte_t *kpte, int level, bool enc) +{ + pgprot_t old_prot, new_prot; + unsigned long pfn, pa, size; + pte_t new_pte; + + switch (level) { + case PG_LEVEL_4K: + pfn = pte_pfn(*kpte); + old_prot = pte_pgprot(*kpte); + break; + case PG_LEVEL_2M: + pfn = pmd_pfn(*(pmd_t *)kpte); + old_prot = pmd_pgprot(*(pmd_t *)kpte); + break; + case PG_LEVEL_1G: + pfn = pud_pfn(*(pud_t *)kpte); + old_prot = pud_pgprot(*(pud_t *)kpte); + break; + default: + return; + } + + new_prot = old_prot; + if (enc) + pgprot_val(new_prot) |= _PAGE_ENC; + else + pgprot_val(new_prot) &= ~_PAGE_ENC; + + /* If prot is same then do nothing. */ + if (pgprot_val(old_prot) == pgprot_val(new_prot)) + return; + + pa = pfn << page_level_shift(level); + size = page_level_size(level); + + /* + * We are going to perform in-place en-/decryption and change the + * physical page attribute from C=1 to C=0 or vice versa. Flush the + * caches to ensure that data gets accessed with the correct C-bit. + */ + clflush_cache_range(__va(pa), size); + + /* Encrypt/decrypt the contents in-place */ + if (enc) + sme_early_encrypt(pa, size); + else + sme_early_decrypt(pa, size); + + /* Change the page encryption mask. */ + new_pte = pfn_pte(pfn, new_prot); + set_pte_atomic(kpte, new_pte); +} + +static int __init early_set_memory_enc_dec(unsigned long vaddr, + unsigned long size, bool enc) +{ + unsigned long vaddr_end, vaddr_next; + unsigned long psize, pmask; + int split_page_size_mask; + int level, ret; + pte_t *kpte; + + vaddr_next = vaddr; + vaddr_end = vaddr + size; + + for (; vaddr < vaddr_end; vaddr = vaddr_next) { + kpte = lookup_address(vaddr, &level); + if (!kpte || pte_none(*kpte)) { + ret = 1; + goto out; + } + + if (level == PG_LEVEL_4K) { + __set_clr_pte_enc(kpte, level, enc); + vaddr_next = (vaddr & PAGE_MASK) + PAGE_SIZE; + continue; + } + + psize = page_level_size(level); + pmask = page_level_mask(level); + + /* + * Check whether we can change the large page in one go. + * We request a split when the address is not aligned and + * the number of pages to set/clear encryption bit is smaller + * than the number of pages in the large page. + */ + if (vaddr == (vaddr & pmask) && + ((vaddr_end - vaddr) >= psize)) { + __set_clr_pte_enc(kpte, level, enc); + vaddr_next = (vaddr & pmask) + psize; + continue; + } + + /* + * The virtual address is part of a larger page, create the next + * level page table mapping (4K or 2M). If it is part of a 2M + * page then we request a split of the large page into 4K + * chunks. A 1GB large page is split into 2M pages, resp. + */ + if (level == PG_LEVEL_2M) + split_page_size_mask = 0; + else + split_page_size_mask = 1 << PG_LEVEL_2M; + + kernel_physical_mapping_init(__pa(vaddr & pmask), + __pa((vaddr_end & pmask) + psize), + split_page_size_mask); + } + + ret = 0; + +out: + __flush_tlb_all(); + return ret; +} + +int __init early_set_memory_decrypted(unsigned long vaddr, unsigned long size) +{ + return early_set_memory_enc_dec(vaddr, size, false); +} + +int __init early_set_memory_encrypted(unsigned long vaddr, unsigned long size) +{ + return early_set_memory_enc_dec(vaddr, size, true); +} + /* * SME and SEV are very similar but they are not the same, so there are * times that the kernel will need to distinguish between SME and SEV. The |