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Diffstat (limited to 'arch/x86/mm/mem_encrypt.c')
-rw-r--r--arch/x86/mm/mem_encrypt.c130
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