arch/x86/mm/mem_encrypt_amd.c

Source file repositories/reference/linux-study-clean/arch/x86/mm/mem_encrypt_amd.c

File Facts

System
Linux kernel
Corpus path
arch/x86/mm/mem_encrypt_amd.c
Extension
.c
Size
15269 bytes
Lines
570
Domain
Architecture Layer
Bucket
arch/x86
Inferred role
Architecture Layer: exported/initcall integration point
Status
integration implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

if (cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) {
			snp_memcpy(sme_early_buffer, src, len, paddr, enc);
			snp_memcpy(dst, sme_early_buffer, len, paddr, !enc);
		} else {
			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);
}

static void __init __sme_early_map_unmap_mem(void *vaddr, unsigned long size,
					     bool map)
{
	unsigned long paddr = (unsigned long)vaddr - __PAGE_OFFSET;
	pmdval_t pmd_flags, pmd;

	/* Use early_pmd_flags but remove the encryption mask */
	pmd_flags = __sme_clr(early_pmd_flags);

	do {
		pmd = map ? (paddr & PMD_MASK) + pmd_flags : 0;
		__early_make_pgtable((unsigned long)vaddr, pmd);

		vaddr += PMD_SIZE;
		paddr += PMD_SIZE;
		size = (size <= PMD_SIZE) ? 0 : size - PMD_SIZE;
	} while (size);

	flush_tlb_local();
}

void __init sme_unmap_bootdata(char *real_mode_data)
{
	struct boot_params *boot_data;
	unsigned long cmdline_paddr;

	if (!cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT))
		return;

	/* Get the command line address before unmapping the real_mode_data */
	boot_data = (struct boot_params *)real_mode_data;
	cmdline_paddr = boot_data->hdr.cmd_line_ptr | ((u64)boot_data->ext_cmd_line_ptr << 32);

	__sme_early_map_unmap_mem(real_mode_data, sizeof(boot_params), false);

	if (!cmdline_paddr)
		return;

	__sme_early_map_unmap_mem(__va(cmdline_paddr), COMMAND_LINE_SIZE, false);
}

void __init sme_map_bootdata(char *real_mode_data)
{
	struct boot_params *boot_data;
	unsigned long cmdline_paddr;

	if (!cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT))
		return;

	__sme_early_map_unmap_mem(real_mode_data, sizeof(boot_params), true);

	/* Get the command line address after mapping the real_mode_data */
	boot_data = (struct boot_params *)real_mode_data;
	cmdline_paddr = boot_data->hdr.cmd_line_ptr | ((u64)boot_data->ext_cmd_line_ptr << 32);

	if (!cmdline_paddr)
		return;

	__sme_early_map_unmap_mem(__va(cmdline_paddr), COMMAND_LINE_SIZE, true);
}

static unsigned long pg_level_to_pfn(int level, pte_t *kpte, pgprot_t *ret_prot)
{
	unsigned long pfn = 0;

Annotation

Implementation Notes