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Subject[tip:x86/mm] x86/mm/encrypt: Move page table helpers into separate translation unit
Commit-ID:  1cd9c22fee3ac21db52a0997d08cf2f065d2c0c0
Gitweb: https://git.kernel.org/tip/1cd9c22fee3ac21db52a0997d08cf2f065d2c0c0
Author: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
AuthorDate: Wed, 31 Jan 2018 16:54:02 +0300
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 13 Feb 2018 15:59:48 +0100

x86/mm/encrypt: Move page table helpers into separate translation unit

There are bunch of functions in mem_encrypt.c that operate on the
identity mapping, which means they want virtual addresses to be equal to
physical one, without PAGE_OFFSET shift.

We also need to avoid paravirtualizaion call there.

Getting this done is tricky. We cannot use usual page table helpers.
It forces us to open-code a lot of things. It makes code ugly and hard
to modify.

We can get it work with the page table helpers, but it requires few
preprocessor tricks. These tricks may have side effects for the rest of
the file.

Let's isolate such functions into own translation unit.

Tested-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20180131135404.40692-2-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/include/asm/mem_encrypt.h | 1 +
arch/x86/mm/Makefile | 14 +-
arch/x86/mm/mem_encrypt.c | 578 +--------------------
.../mm/{mem_encrypt.c => mem_encrypt_identity.c} | 479 +----------------
4 files changed, 31 insertions(+), 1041 deletions(-)

diff --git a/arch/x86/include/asm/mem_encrypt.h b/arch/x86/include/asm/mem_encrypt.h
index 22c5f3e..8fe61ad 100644
--- a/arch/x86/include/asm/mem_encrypt.h
+++ b/arch/x86/include/asm/mem_encrypt.h
@@ -22,6 +22,7 @@
#ifdef CONFIG_AMD_MEM_ENCRYPT

extern u64 sme_me_mask;
+extern bool sev_enabled;

void sme_encrypt_execute(unsigned long encrypted_kernel_vaddr,
unsigned long decrypted_kernel_vaddr,
diff --git a/arch/x86/mm/Makefile b/arch/x86/mm/Makefile
index 27e9e90..03c6c85 100644
--- a/arch/x86/mm/Makefile
+++ b/arch/x86/mm/Makefile
@@ -1,12 +1,15 @@
# SPDX-License-Identifier: GPL-2.0
-# Kernel does not boot with instrumentation of tlb.c and mem_encrypt.c
-KCOV_INSTRUMENT_tlb.o := n
-KCOV_INSTRUMENT_mem_encrypt.o := n
+# Kernel does not boot with instrumentation of tlb.c and mem_encrypt*.c
+KCOV_INSTRUMENT_tlb.o := n
+KCOV_INSTRUMENT_mem_encrypt.o := n
+KCOV_INSTRUMENT_mem_encrypt_identity.o := n

-KASAN_SANITIZE_mem_encrypt.o := n
+KASAN_SANITIZE_mem_encrypt.o := n
+KASAN_SANITIZE_mem_encrypt_identity.o := n

ifdef CONFIG_FUNCTION_TRACER
-CFLAGS_REMOVE_mem_encrypt.o = -pg
+CFLAGS_REMOVE_mem_encrypt.o = -pg
+CFLAGS_REMOVE_mem_encrypt_identity.o = -pg
endif

obj-y := init.o init_$(BITS).o fault.o ioremap.o extable.o pageattr.o mmap.o \
@@ -47,4 +50,5 @@ obj-$(CONFIG_RANDOMIZE_MEMORY) += kaslr.o
obj-$(CONFIG_PAGE_TABLE_ISOLATION) += pti.o

obj-$(CONFIG_AMD_MEM_ENCRYPT) += mem_encrypt.o
+obj-$(CONFIG_AMD_MEM_ENCRYPT) += mem_encrypt_identity.o
obj-$(CONFIG_AMD_MEM_ENCRYPT) += mem_encrypt_boot.o
diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index 1a53071..3a1b5fe 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -25,17 +25,12 @@
#include <asm/bootparam.h>
#include <asm/set_memory.h>
#include <asm/cacheflush.h>
-#include <asm/sections.h>
#include <asm/processor-flags.h>
#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";
-
/*
* 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
@@ -46,7 +41,7 @@ EXPORT_SYMBOL(sme_me_mask);
DEFINE_STATIC_KEY_FALSE(sev_enable_key);
EXPORT_SYMBOL_GPL(sev_enable_key);

-static bool sev_enabled __section(.data);
+bool sev_enabled __section(.data);

/* Buffer used for early in-place encryption by BSP, no locking needed */
static char sme_early_buffer[PAGE_SIZE] __aligned(PAGE_SIZE);
@@ -463,574 +458,3 @@ void swiotlb_set_mem_attributes(void *vaddr, unsigned long size)
/* Make the SWIOTLB buffer area decrypted */
set_memory_decrypted((unsigned long)vaddr, size >> PAGE_SHIFT);
}
-
-struct sme_populate_pgd_data {
- void *pgtable_area;
- pgd_t *pgd;
-
- pmdval_t pmd_flags;
- pteval_t pte_flags;
- unsigned long paddr;
-
- unsigned long vaddr;
- unsigned long vaddr_end;
-};
-
-static void __init sme_clear_pgd(struct sme_populate_pgd_data *ppd)
-{
- unsigned long pgd_start, pgd_end, pgd_size;
- pgd_t *pgd_p;
-
- pgd_start = ppd->vaddr & PGDIR_MASK;
- pgd_end = ppd->vaddr_end & PGDIR_MASK;
-
- pgd_size = (((pgd_end - pgd_start) / PGDIR_SIZE) + 1) * sizeof(pgd_t);
-
- pgd_p = ppd->pgd + pgd_index(ppd->vaddr);
-
- memset(pgd_p, 0, pgd_size);
-}
-
-#define PGD_FLAGS _KERNPG_TABLE_NOENC
-#define P4D_FLAGS _KERNPG_TABLE_NOENC
-#define PUD_FLAGS _KERNPG_TABLE_NOENC
-#define PMD_FLAGS _KERNPG_TABLE_NOENC
-
-#define PMD_FLAGS_LARGE (__PAGE_KERNEL_LARGE_EXEC & ~_PAGE_GLOBAL)
-
-#define PMD_FLAGS_DEC PMD_FLAGS_LARGE
-#define PMD_FLAGS_DEC_WP ((PMD_FLAGS_DEC & ~_PAGE_CACHE_MASK) | \
- (_PAGE_PAT | _PAGE_PWT))
-
-#define PMD_FLAGS_ENC (PMD_FLAGS_LARGE | _PAGE_ENC)
-
-#define PTE_FLAGS (__PAGE_KERNEL_EXEC & ~_PAGE_GLOBAL)
-
-#define PTE_FLAGS_DEC PTE_FLAGS
-#define PTE_FLAGS_DEC_WP ((PTE_FLAGS_DEC & ~_PAGE_CACHE_MASK) | \
- (_PAGE_PAT | _PAGE_PWT))
-
-#define PTE_FLAGS_ENC (PTE_FLAGS | _PAGE_ENC)
-
-static pmd_t __init *sme_prepare_pgd(struct sme_populate_pgd_data *ppd)
-{
- pgd_t *pgd_p;
- p4d_t *p4d_p;
- pud_t *pud_p;
- pmd_t *pmd_p;
-
- pgd_p = ppd->pgd + pgd_index(ppd->vaddr);
- if (native_pgd_val(*pgd_p)) {
- if (IS_ENABLED(CONFIG_X86_5LEVEL))
- p4d_p = (p4d_t *)(native_pgd_val(*pgd_p) & ~PTE_FLAGS_MASK);
- else
- pud_p = (pud_t *)(native_pgd_val(*pgd_p) & ~PTE_FLAGS_MASK);
- } else {
- pgd_t pgd;
-
- if (IS_ENABLED(CONFIG_X86_5LEVEL)) {
- p4d_p = ppd->pgtable_area;
- memset(p4d_p, 0, sizeof(*p4d_p) * PTRS_PER_P4D);
- ppd->pgtable_area += sizeof(*p4d_p) * PTRS_PER_P4D;
-
- pgd = native_make_pgd((pgdval_t)p4d_p + PGD_FLAGS);
- } else {
- pud_p = ppd->pgtable_area;
- memset(pud_p, 0, sizeof(*pud_p) * PTRS_PER_PUD);
- ppd->pgtable_area += sizeof(*pud_p) * PTRS_PER_PUD;
-
- pgd = native_make_pgd((pgdval_t)pud_p + PGD_FLAGS);
- }
- native_set_pgd(pgd_p, pgd);
- }
-
- if (IS_ENABLED(CONFIG_X86_5LEVEL)) {
- p4d_p += p4d_index(ppd->vaddr);
- if (native_p4d_val(*p4d_p)) {
- pud_p = (pud_t *)(native_p4d_val(*p4d_p) & ~PTE_FLAGS_MASK);
- } else {
- p4d_t p4d;
-
- pud_p = ppd->pgtable_area;
- memset(pud_p, 0, sizeof(*pud_p) * PTRS_PER_PUD);
- ppd->pgtable_area += sizeof(*pud_p) * PTRS_PER_PUD;
-
- p4d = native_make_p4d((pudval_t)pud_p + P4D_FLAGS);
- native_set_p4d(p4d_p, p4d);
- }
- }
-
- pud_p += pud_index(ppd->vaddr);
- if (native_pud_val(*pud_p)) {
- if (native_pud_val(*pud_p) & _PAGE_PSE)
- return NULL;
-
- pmd_p = (pmd_t *)(native_pud_val(*pud_p) & ~PTE_FLAGS_MASK);
- } else {
- pud_t pud;
-
- pmd_p = ppd->pgtable_area;
- memset(pmd_p, 0, sizeof(*pmd_p) * PTRS_PER_PMD);
- ppd->pgtable_area += sizeof(*pmd_p) * PTRS_PER_PMD;
-
- pud = native_make_pud((pmdval_t)pmd_p + PUD_FLAGS);
- native_set_pud(pud_p, pud);
- }
-
- return pmd_p;
-}
-
-static void __init sme_populate_pgd_large(struct sme_populate_pgd_data *ppd)
-{
- pmd_t *pmd_p;
-
- pmd_p = sme_prepare_pgd(ppd);
- if (!pmd_p)
- return;
-
- pmd_p += pmd_index(ppd->vaddr);
- if (!native_pmd_val(*pmd_p) || !(native_pmd_val(*pmd_p) & _PAGE_PSE))
- native_set_pmd(pmd_p, native_make_pmd(ppd->paddr | ppd->pmd_flags));
-}
-
-static void __init sme_populate_pgd(struct sme_populate_pgd_data *ppd)
-{
- pmd_t *pmd_p;
- pte_t *pte_p;
-
- pmd_p = sme_prepare_pgd(ppd);
- if (!pmd_p)
- return;
-
- pmd_p += pmd_index(ppd->vaddr);
- if (native_pmd_val(*pmd_p)) {
- if (native_pmd_val(*pmd_p) & _PAGE_PSE)
- return;
-
- pte_p = (pte_t *)(native_pmd_val(*pmd_p) & ~PTE_FLAGS_MASK);
- } else {
- pmd_t pmd;
-
- pte_p = ppd->pgtable_area;
- memset(pte_p, 0, sizeof(*pte_p) * PTRS_PER_PTE);
- ppd->pgtable_area += sizeof(*pte_p) * PTRS_PER_PTE;
-
- pmd = native_make_pmd((pteval_t)pte_p + PMD_FLAGS);
- native_set_pmd(pmd_p, pmd);
- }
-
- pte_p += pte_index(ppd->vaddr);
- if (!native_pte_val(*pte_p))
- native_set_pte(pte_p, native_make_pte(ppd->paddr | ppd->pte_flags));
-}
-
-static void __init __sme_map_range_pmd(struct sme_populate_pgd_data *ppd)
-{
- while (ppd->vaddr < ppd->vaddr_end) {
- sme_populate_pgd_large(ppd);
-
- ppd->vaddr += PMD_PAGE_SIZE;
- ppd->paddr += PMD_PAGE_SIZE;
- }
-}
-
-static void __init __sme_map_range_pte(struct sme_populate_pgd_data *ppd)
-{
- while (ppd->vaddr < ppd->vaddr_end) {
- sme_populate_pgd(ppd);
-
- ppd->vaddr += PAGE_SIZE;
- ppd->paddr += PAGE_SIZE;
- }
-}
-
-static void __init __sme_map_range(struct sme_populate_pgd_data *ppd,
- pmdval_t pmd_flags, pteval_t pte_flags)
-{
- unsigned long vaddr_end;
-
- ppd->pmd_flags = pmd_flags;
- ppd->pte_flags = pte_flags;
-
- /* Save original end value since we modify the struct value */
- vaddr_end = ppd->vaddr_end;
-
- /* If start is not 2MB aligned, create PTE entries */
- ppd->vaddr_end = ALIGN(ppd->vaddr, PMD_PAGE_SIZE);
- __sme_map_range_pte(ppd);
-
- /* Create PMD entries */
- ppd->vaddr_end = vaddr_end & PMD_PAGE_MASK;
- __sme_map_range_pmd(ppd);
-
- /* If end is not 2MB aligned, create PTE entries */
- ppd->vaddr_end = vaddr_end;
- __sme_map_range_pte(ppd);
-}
-
-static void __init sme_map_range_encrypted(struct sme_populate_pgd_data *ppd)
-{
- __sme_map_range(ppd, PMD_FLAGS_ENC, PTE_FLAGS_ENC);
-}
-
-static void __init sme_map_range_decrypted(struct sme_populate_pgd_data *ppd)
-{
- __sme_map_range(ppd, PMD_FLAGS_DEC, PTE_FLAGS_DEC);
-}
-
-static void __init sme_map_range_decrypted_wp(struct sme_populate_pgd_data *ppd)
-{
- __sme_map_range(ppd, PMD_FLAGS_DEC_WP, PTE_FLAGS_DEC_WP);
-}
-
-static unsigned long __init sme_pgtable_calc(unsigned long len)
-{
- unsigned long p4d_size, pud_size, pmd_size, pte_size;
- unsigned long total;
-
- /*
- * Perform a relatively simplistic calculation of the pagetable
- * entries that are needed. Those mappings will be covered mostly
- * by 2MB PMD entries so we can conservatively calculate the required
- * number of P4D, PUD and PMD structures needed to perform the
- * mappings. For mappings that are not 2MB aligned, PTE mappings
- * would be needed for the start and end portion of the address range
- * that fall outside of the 2MB alignment. This results in, at most,
- * two extra pages to hold PTE entries for each range that is mapped.
- * Incrementing the count for each covers the case where the addresses
- * cross entries.
- */
- if (IS_ENABLED(CONFIG_X86_5LEVEL)) {
- p4d_size = (ALIGN(len, PGDIR_SIZE) / PGDIR_SIZE) + 1;
- p4d_size *= sizeof(p4d_t) * PTRS_PER_P4D;
- pud_size = (ALIGN(len, P4D_SIZE) / P4D_SIZE) + 1;
- pud_size *= sizeof(pud_t) * PTRS_PER_PUD;
- } else {
- p4d_size = 0;
- pud_size = (ALIGN(len, PGDIR_SIZE) / PGDIR_SIZE) + 1;
- pud_size *= sizeof(pud_t) * PTRS_PER_PUD;
- }
- pmd_size = (ALIGN(len, PUD_SIZE) / PUD_SIZE) + 1;
- pmd_size *= sizeof(pmd_t) * PTRS_PER_PMD;
- pte_size = 2 * sizeof(pte_t) * PTRS_PER_PTE;
-
- total = p4d_size + pud_size + pmd_size + pte_size;
-
- /*
- * Now calculate the added pagetable structures needed to populate
- * the new pagetables.
- */
- if (IS_ENABLED(CONFIG_X86_5LEVEL)) {
- p4d_size = ALIGN(total, PGDIR_SIZE) / PGDIR_SIZE;
- p4d_size *= sizeof(p4d_t) * PTRS_PER_P4D;
- pud_size = ALIGN(total, P4D_SIZE) / P4D_SIZE;
- pud_size *= sizeof(pud_t) * PTRS_PER_PUD;
- } else {
- p4d_size = 0;
- pud_size = ALIGN(total, PGDIR_SIZE) / PGDIR_SIZE;
- pud_size *= sizeof(pud_t) * PTRS_PER_PUD;
- }
- pmd_size = ALIGN(total, PUD_SIZE) / PUD_SIZE;
- pmd_size *= sizeof(pmd_t) * PTRS_PER_PMD;
-
- total += p4d_size + pud_size + pmd_size;
-
- return total;
-}
-
-void __init __nostackprotector sme_encrypt_kernel(struct boot_params *bp)
-{
- unsigned long workarea_start, workarea_end, workarea_len;
- unsigned long execute_start, execute_end, execute_len;
- unsigned long kernel_start, kernel_end, kernel_len;
- unsigned long initrd_start, initrd_end, initrd_len;
- struct sme_populate_pgd_data ppd;
- unsigned long pgtable_area_len;
- unsigned long decrypted_base;
-
- if (!sme_active())
- return;
-
- /*
- * Prepare for encrypting the kernel and initrd by building new
- * pagetables with the necessary attributes needed to encrypt the
- * kernel in place.
- *
- * One range of virtual addresses will map the memory occupied
- * by the kernel and initrd as encrypted.
- *
- * Another range of virtual addresses will map the memory occupied
- * by the kernel and initrd as decrypted and write-protected.
- *
- * The use of write-protect attribute will prevent any of the
- * memory from being cached.
- */
-
- /* Physical addresses gives us the identity mapped virtual addresses */
- kernel_start = __pa_symbol(_text);
- kernel_end = ALIGN(__pa_symbol(_end), PMD_PAGE_SIZE);
- kernel_len = kernel_end - kernel_start;
-
- initrd_start = 0;
- initrd_end = 0;
- initrd_len = 0;
-#ifdef CONFIG_BLK_DEV_INITRD
- initrd_len = (unsigned long)bp->hdr.ramdisk_size |
- ((unsigned long)bp->ext_ramdisk_size << 32);
- if (initrd_len) {
- initrd_start = (unsigned long)bp->hdr.ramdisk_image |
- ((unsigned long)bp->ext_ramdisk_image << 32);
- initrd_end = PAGE_ALIGN(initrd_start + initrd_len);
- initrd_len = initrd_end - initrd_start;
- }
-#endif
-
- /* Set the encryption workarea to be immediately after the kernel */
- workarea_start = kernel_end;
-
- /*
- * Calculate required number of workarea bytes needed:
- * executable encryption area size:
- * stack page (PAGE_SIZE)
- * encryption routine page (PAGE_SIZE)
- * intermediate copy buffer (PMD_PAGE_SIZE)
- * pagetable structures for the encryption of the kernel
- * pagetable structures for workarea (in case not currently mapped)
- */
- execute_start = workarea_start;
- execute_end = execute_start + (PAGE_SIZE * 2) + PMD_PAGE_SIZE;
- execute_len = execute_end - execute_start;
-
- /*
- * One PGD for both encrypted and decrypted mappings and a set of
- * PUDs and PMDs for each of the encrypted and decrypted mappings.
- */
- pgtable_area_len = sizeof(pgd_t) * PTRS_PER_PGD;
- pgtable_area_len += sme_pgtable_calc(execute_end - kernel_start) * 2;
- if (initrd_len)
- pgtable_area_len += sme_pgtable_calc(initrd_len) * 2;
-
- /* PUDs and PMDs needed in the current pagetables for the workarea */
- pgtable_area_len += sme_pgtable_calc(execute_len + pgtable_area_len);
-
- /*
- * The total workarea includes the executable encryption area and
- * the pagetable area. The start of the workarea is already 2MB
- * aligned, align the end of the workarea on a 2MB boundary so that
- * we don't try to create/allocate PTE entries from the workarea
- * before it is mapped.
- */
- workarea_len = execute_len + pgtable_area_len;
- workarea_end = ALIGN(workarea_start + workarea_len, PMD_PAGE_SIZE);
-
- /*
- * Set the address to the start of where newly created pagetable
- * structures (PGDs, PUDs and PMDs) will be allocated. New pagetable
- * structures are created when the workarea is added to the current
- * pagetables and when the new encrypted and decrypted kernel
- * mappings are populated.
- */
- ppd.pgtable_area = (void *)execute_end;
-
- /*
- * Make sure the current pagetable structure has entries for
- * addressing the workarea.
- */
- ppd.pgd = (pgd_t *)native_read_cr3_pa();
- ppd.paddr = workarea_start;
- ppd.vaddr = workarea_start;
- ppd.vaddr_end = workarea_end;
- sme_map_range_decrypted(&ppd);
-
- /* Flush the TLB - no globals so cr3 is enough */
- native_write_cr3(__native_read_cr3());
-
- /*
- * A new pagetable structure is being built to allow for the kernel
- * and initrd to be encrypted. It starts with an empty PGD that will
- * then be populated with new PUDs and PMDs as the encrypted and
- * decrypted kernel mappings are created.
- */
- ppd.pgd = ppd.pgtable_area;
- memset(ppd.pgd, 0, sizeof(pgd_t) * PTRS_PER_PGD);
- ppd.pgtable_area += sizeof(pgd_t) * PTRS_PER_PGD;
-
- /*
- * A different PGD index/entry must be used to get different
- * pagetable entries for the decrypted mapping. Choose the next
- * PGD index and convert it to a virtual address to be used as
- * the base of the mapping.
- */
- decrypted_base = (pgd_index(workarea_end) + 1) & (PTRS_PER_PGD - 1);
- if (initrd_len) {
- unsigned long check_base;
-
- check_base = (pgd_index(initrd_end) + 1) & (PTRS_PER_PGD - 1);
- decrypted_base = max(decrypted_base, check_base);
- }
- decrypted_base <<= PGDIR_SHIFT;
-
- /* Add encrypted kernel (identity) mappings */
- ppd.paddr = kernel_start;
- ppd.vaddr = kernel_start;
- ppd.vaddr_end = kernel_end;
- sme_map_range_encrypted(&ppd);
-
- /* Add decrypted, write-protected kernel (non-identity) mappings */
- ppd.paddr = kernel_start;
- ppd.vaddr = kernel_start + decrypted_base;
- ppd.vaddr_end = kernel_end + decrypted_base;
- sme_map_range_decrypted_wp(&ppd);
-
- if (initrd_len) {
- /* Add encrypted initrd (identity) mappings */
- ppd.paddr = initrd_start;
- ppd.vaddr = initrd_start;
- ppd.vaddr_end = initrd_end;
- sme_map_range_encrypted(&ppd);
- /*
- * Add decrypted, write-protected initrd (non-identity) mappings
- */
- ppd.paddr = initrd_start;
- ppd.vaddr = initrd_start + decrypted_base;
- ppd.vaddr_end = initrd_end + decrypted_base;
- sme_map_range_decrypted_wp(&ppd);
- }
-
- /* Add decrypted workarea mappings to both kernel mappings */
- ppd.paddr = workarea_start;
- ppd.vaddr = workarea_start;
- ppd.vaddr_end = workarea_end;
- sme_map_range_decrypted(&ppd);
-
- ppd.paddr = workarea_start;
- ppd.vaddr = workarea_start + decrypted_base;
- ppd.vaddr_end = workarea_end + decrypted_base;
- sme_map_range_decrypted(&ppd);
-
- /* Perform the encryption */
- sme_encrypt_execute(kernel_start, kernel_start + decrypted_base,
- kernel_len, workarea_start, (unsigned long)ppd.pgd);
-
- if (initrd_len)
- sme_encrypt_execute(initrd_start, initrd_start + decrypted_base,
- initrd_len, workarea_start,
- (unsigned long)ppd.pgd);
-
- /*
- * At this point we are running encrypted. Remove the mappings for
- * the decrypted areas - all that is needed for this is to remove
- * the PGD entry/entries.
- */
- ppd.vaddr = kernel_start + decrypted_base;
- ppd.vaddr_end = kernel_end + decrypted_base;
- sme_clear_pgd(&ppd);
-
- if (initrd_len) {
- ppd.vaddr = initrd_start + decrypted_base;
- ppd.vaddr_end = initrd_end + decrypted_base;
- sme_clear_pgd(&ppd);
- }
-
- ppd.vaddr = workarea_start + decrypted_base;
- ppd.vaddr_end = workarea_end + decrypted_base;
- sme_clear_pgd(&ppd);
-
- /* Flush the TLB - no globals so cr3 is enough */
- native_write_cr3(__native_read_cr3());
-}
-
-void __init __nostackprotector sme_enable(struct boot_params *bp)
-{
- const char *cmdline_ptr, *cmdline_arg, *cmdline_on, *cmdline_off;
- unsigned int eax, ebx, ecx, edx;
- unsigned long feature_mask;
- bool active_by_default;
- unsigned long me_mask;
- char buffer[16];
- u64 msr;
-
- /* Check for the SME/SEV support leaf */
- eax = 0x80000000;
- ecx = 0;
- native_cpuid(&eax, &ebx, &ecx, &edx);
- if (eax < 0x8000001f)
- return;
-
-#define AMD_SME_BIT BIT(0)
-#define AMD_SEV_BIT BIT(1)
- /*
- * Set the feature mask (SME or SEV) based on whether we are
- * running under a hypervisor.
- */
- eax = 1;
- ecx = 0;
- native_cpuid(&eax, &ebx, &ecx, &edx);
- feature_mask = (ecx & BIT(31)) ? AMD_SEV_BIT : AMD_SME_BIT;
-
- /*
- * Check for the SME/SEV feature:
- * CPUID Fn8000_001F[EAX]
- * - Bit 0 - Secure Memory Encryption support
- * - Bit 1 - Secure Encrypted Virtualization support
- * CPUID Fn8000_001F[EBX]
- * - Bits 5:0 - Pagetable bit position used to indicate encryption
- */
- eax = 0x8000001f;
- ecx = 0;
- native_cpuid(&eax, &ebx, &ecx, &edx);
- if (!(eax & feature_mask))
- return;
-
- me_mask = 1UL << (ebx & 0x3f);
-
- /* Check if memory encryption is enabled */
- if (feature_mask == AMD_SME_BIT) {
- /* For SME, check the SYSCFG MSR */
- msr = __rdmsr(MSR_K8_SYSCFG);
- if (!(msr & MSR_K8_SYSCFG_MEM_ENCRYPT))
- return;
- } else {
- /* For SEV, check the SEV MSR */
- msr = __rdmsr(MSR_AMD64_SEV);
- if (!(msr & MSR_AMD64_SEV_ENABLED))
- return;
-
- /* SEV state cannot be controlled by a command line option */
- sme_me_mask = me_mask;
- sev_enabled = true;
- return;
- }
-
- /*
- * Fixups have not been applied to phys_base yet and we're running
- * identity mapped, so we must obtain the address to the SME command
- * line argument data using rip-relative addressing.
- */
- asm ("lea sme_cmdline_arg(%%rip), %0"
- : "=r" (cmdline_arg)
- : "p" (sme_cmdline_arg));
- asm ("lea sme_cmdline_on(%%rip), %0"
- : "=r" (cmdline_on)
- : "p" (sme_cmdline_on));
- asm ("lea sme_cmdline_off(%%rip), %0"
- : "=r" (cmdline_off)
- : "p" (sme_cmdline_off));
-
- if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT))
- active_by_default = true;
- else
- active_by_default = false;
-
- cmdline_ptr = (const char *)((u64)bp->hdr.cmd_line_ptr |
- ((u64)bp->ext_cmd_line_ptr << 32));
-
- cmdline_find_option(cmdline_ptr, cmdline_arg, buffer, sizeof(buffer));
-
- if (!strncmp(buffer, cmdline_on, sizeof(buffer)))
- sme_me_mask = me_mask;
- else if (!strncmp(buffer, cmdline_off, sizeof(buffer)))
- sme_me_mask = 0;
- else
- sme_me_mask = active_by_default ? me_mask : 0;
-}
diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt_identity.c
similarity index 59%
copy from arch/x86/mm/mem_encrypt.c
copy to arch/x86/mm/mem_encrypt_identity.c
index 1a53071..a28978a 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt_identity.c
@@ -12,461 +12,39 @@

#define DISABLE_BRANCH_PROFILING

-#include <linux/linkage.h>
-#include <linux/init.h>
#include <linux/mm.h>
-#include <linux/dma-direct.h>
-#include <linux/swiotlb.h>
#include <linux/mem_encrypt.h>

-#include <asm/tlbflush.h>
-#include <asm/fixmap.h>
#include <asm/setup.h>
-#include <asm/bootparam.h>
-#include <asm/set_memory.h>
-#include <asm/cacheflush.h>
#include <asm/sections.h>
-#include <asm/processor-flags.h>
-#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";
-
-/*
- * 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
- * section is later cleared.
- */
-u64 sme_me_mask __section(.data) = 0;
-EXPORT_SYMBOL(sme_me_mask);
-DEFINE_STATIC_KEY_FALSE(sev_enable_key);
-EXPORT_SYMBOL_GPL(sev_enable_key);
-
-static bool sev_enabled __section(.data);
-
-/* 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;
-
- 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);
-}
-
-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);
-
- __native_flush_tlb();
-}
-
-void __init sme_unmap_bootdata(char *real_mode_data)
-{
- struct boot_params *boot_data;
- unsigned long cmdline_paddr;
-
- if (!sme_active())
- 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 (!sme_active())
- 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);
-}
-
-void __init sme_early_init(void)
-{
- unsigned int i;
-
- if (!sme_me_mask)
- return;
-
- early_pmd_flags = __sme_set(early_pmd_flags);
-
- __supported_pte_mask = __sme_set(__supported_pte_mask);
-
- /* Update the protection map with memory encryption mask */
- for (i = 0; i < ARRAY_SIZE(protection_map); i++)
- protection_map[i] = pgprot_encrypted(protection_map[i]);
-
- if (sev_active())
- swiotlb_force = SWIOTLB_FORCE;
-}
-
-static void *sev_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
- gfp_t gfp, unsigned long attrs)
-{
- unsigned long dma_mask;
- unsigned int order;
- struct page *page;
- void *vaddr = NULL;
-
- dma_mask = dma_alloc_coherent_mask(dev, gfp);
- order = get_order(size);
-
- /*
- * Memory will be memset to zero after marking decrypted, so don't
- * bother clearing it before.
- */
- gfp &= ~__GFP_ZERO;
-
- page = alloc_pages_node(dev_to_node(dev), gfp, order);
- if (page) {
- dma_addr_t addr;
-
- /*
- * Since we will be clearing the encryption bit, check the
- * mask with it already cleared.
- */
- addr = __sme_clr(phys_to_dma(dev, page_to_phys(page)));
- if ((addr + size) > dma_mask) {
- __free_pages(page, get_order(size));
- } else {
- vaddr = page_address(page);
- *dma_handle = addr;
- }
- }
-
- if (!vaddr)
- vaddr = swiotlb_alloc_coherent(dev, size, dma_handle, gfp);
-
- if (!vaddr)
- return NULL;
-
- /* Clear the SME encryption bit for DMA use if not swiotlb area */
- if (!is_swiotlb_buffer(dma_to_phys(dev, *dma_handle))) {
- set_memory_decrypted((unsigned long)vaddr, 1 << order);
- memset(vaddr, 0, PAGE_SIZE << order);
- *dma_handle = __sme_clr(*dma_handle);
- }
-
- return vaddr;
-}
-
-static void sev_free(struct device *dev, size_t size, void *vaddr,
- dma_addr_t dma_handle, unsigned long attrs)
-{
- /* Set the SME encryption bit for re-use if not swiotlb area */
- if (!is_swiotlb_buffer(dma_to_phys(dev, dma_handle)))
- set_memory_encrypted((unsigned long)vaddr,
- 1 << get_order(size));
-
- 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
- * sme_active() and sev_active() functions are used for this. When a
- * distinction isn't needed, the mem_encrypt_active() function can be used.
- *
- * The trampoline code is a good example for this requirement. Before
- * paging is activated, SME will access all memory as decrypted, but SEV
- * will access all memory as encrypted. So, when APs are being brought
- * up under SME the trampoline area cannot be encrypted, whereas under SEV
- * the trampoline area must be encrypted.
- */
-bool sme_active(void)
-{
- return sme_me_mask && !sev_enabled;
-}
-EXPORT_SYMBOL(sme_active);
-
-bool sev_active(void)
-{
- return sme_me_mask && sev_enabled;
-}
-EXPORT_SYMBOL(sev_active);
-
-static const struct dma_map_ops sev_dma_ops = {
- .alloc = sev_alloc,
- .free = sev_free,
- .map_page = swiotlb_map_page,
- .unmap_page = swiotlb_unmap_page,
- .map_sg = swiotlb_map_sg_attrs,
- .unmap_sg = swiotlb_unmap_sg_attrs,
- .sync_single_for_cpu = swiotlb_sync_single_for_cpu,
- .sync_single_for_device = swiotlb_sync_single_for_device,
- .sync_sg_for_cpu = swiotlb_sync_sg_for_cpu,
- .sync_sg_for_device = swiotlb_sync_sg_for_device,
- .mapping_error = swiotlb_dma_mapping_error,
-};
-
-/* Architecture __weak replacement functions */
-void __init mem_encrypt_init(void)
-{
- if (!sme_me_mask)
- return;
+#define PGD_FLAGS _KERNPG_TABLE_NOENC
+#define P4D_FLAGS _KERNPG_TABLE_NOENC
+#define PUD_FLAGS _KERNPG_TABLE_NOENC
+#define PMD_FLAGS _KERNPG_TABLE_NOENC

- /* Call into SWIOTLB to update the SWIOTLB DMA buffers */
- swiotlb_update_mem_attributes();
+#define PMD_FLAGS_LARGE (__PAGE_KERNEL_LARGE_EXEC & ~_PAGE_GLOBAL)

- /*
- * With SEV, DMA operations cannot use encryption. New DMA ops
- * are required in order to mark the DMA areas as decrypted or
- * to use bounce buffers.
- */
- if (sev_active())
- dma_ops = &sev_dma_ops;
+#define PMD_FLAGS_DEC PMD_FLAGS_LARGE
+#define PMD_FLAGS_DEC_WP ((PMD_FLAGS_DEC & ~_PAGE_CACHE_MASK) | \
+ (_PAGE_PAT | _PAGE_PWT))

- /*
- * With SEV, we need to unroll the rep string I/O instructions.
- */
- if (sev_active())
- static_branch_enable(&sev_enable_key);
+#define PMD_FLAGS_ENC (PMD_FLAGS_LARGE | _PAGE_ENC)

- pr_info("AMD %s active\n",
- sev_active() ? "Secure Encrypted Virtualization (SEV)"
- : "Secure Memory Encryption (SME)");
-}
+#define PTE_FLAGS (__PAGE_KERNEL_EXEC & ~_PAGE_GLOBAL)

-void swiotlb_set_mem_attributes(void *vaddr, unsigned long size)
-{
- WARN(PAGE_ALIGN(size) != size,
- "size is not page-aligned (%#lx)\n", size);
+#define PTE_FLAGS_DEC PTE_FLAGS
+#define PTE_FLAGS_DEC_WP ((PTE_FLAGS_DEC & ~_PAGE_CACHE_MASK) | \
+ (_PAGE_PAT | _PAGE_PWT))

- /* Make the SWIOTLB buffer area decrypted */
- set_memory_decrypted((unsigned long)vaddr, size >> PAGE_SHIFT);
-}
+#define PTE_FLAGS_ENC (PTE_FLAGS | _PAGE_ENC)

struct sme_populate_pgd_data {
- void *pgtable_area;
- pgd_t *pgd;
+ void *pgtable_area;
+ pgd_t *pgd;

pmdval_t pmd_flags;
pteval_t pte_flags;
@@ -476,6 +54,10 @@ struct sme_populate_pgd_data {
unsigned long vaddr_end;
};

+static char sme_cmdline_arg[] __initdata = "mem_encrypt";
+static char sme_cmdline_on[] __initdata = "on";
+static char sme_cmdline_off[] __initdata = "off";
+
static void __init sme_clear_pgd(struct sme_populate_pgd_data *ppd)
{
unsigned long pgd_start, pgd_end, pgd_size;
@@ -491,27 +73,6 @@ static void __init sme_clear_pgd(struct sme_populate_pgd_data *ppd)
memset(pgd_p, 0, pgd_size);
}

-#define PGD_FLAGS _KERNPG_TABLE_NOENC
-#define P4D_FLAGS _KERNPG_TABLE_NOENC
-#define PUD_FLAGS _KERNPG_TABLE_NOENC
-#define PMD_FLAGS _KERNPG_TABLE_NOENC
-
-#define PMD_FLAGS_LARGE (__PAGE_KERNEL_LARGE_EXEC & ~_PAGE_GLOBAL)
-
-#define PMD_FLAGS_DEC PMD_FLAGS_LARGE
-#define PMD_FLAGS_DEC_WP ((PMD_FLAGS_DEC & ~_PAGE_CACHE_MASK) | \
- (_PAGE_PAT | _PAGE_PWT))
-
-#define PMD_FLAGS_ENC (PMD_FLAGS_LARGE | _PAGE_ENC)
-
-#define PTE_FLAGS (__PAGE_KERNEL_EXEC & ~_PAGE_GLOBAL)
-
-#define PTE_FLAGS_DEC PTE_FLAGS
-#define PTE_FLAGS_DEC_WP ((PTE_FLAGS_DEC & ~_PAGE_CACHE_MASK) | \
- (_PAGE_PAT | _PAGE_PWT))
-
-#define PTE_FLAGS_ENC (PTE_FLAGS | _PAGE_ENC)
-
static pmd_t __init *sme_prepare_pgd(struct sme_populate_pgd_data *ppd)
{
pgd_t *pgd_p;
\
 
 \ /
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