401 lines
10 KiB
C
401 lines
10 KiB
C
|
/*
|
||
|
|
* AMD Memory Encryption Support
|
||
|
|
*
|
||
|
|
* Copyright (C) 2016 Advanced Micro Devices, Inc.
|
||
|
|
*
|
||
|
|
* Author: Tom Lendacky <thomas.lendacky@amd.com>
|
||
|
|
*
|
||
|
|
* This program is free software; you can redistribute it and/or modify
|
||
|
|
* it under the terms of the GNU General Public License version 2 as
|
||
|
|
* published by the Free Software Foundation.
|
||
|
|
*/
|
||
|
|
|
||
|
|
#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/processor-flags.h>
|
||
|
|
#include <asm/msr.h>
|
||
|
|
#include <asm/cmdline.h>
|
||
|
|
|
||
|
|
#include "mm_internal.h"
|
||
|
|
|
||
|
|
/*
|
||
|
|
* 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);
|
||
|
|
|
||
|
|
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 __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_SHIFT;
|
||
|
|
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);
|
||
|
|
|
||
|
|
/* Architecture __weak replacement functions */
|
||
|
|
void __init mem_encrypt_free_decrypted_mem(void)
|
||
|
|
{
|
||
|
|
unsigned long vaddr, vaddr_end, npages;
|
||
|
|
int r;
|
||
|
|
|
||
|
|
vaddr = (unsigned long)__start_bss_decrypted_unused;
|
||
|
|
vaddr_end = (unsigned long)__end_bss_decrypted;
|
||
|
|
npages = (vaddr_end - vaddr) >> PAGE_SHIFT;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* The unused memory range was mapped decrypted, change the encryption
|
||
|
|
* attribute from decrypted to encrypted before freeing it.
|
||
|
|
*/
|
||
|
|
if (mem_encrypt_active()) {
|
||
|
|
r = set_memory_encrypted(vaddr, npages);
|
||
|
|
if (r) {
|
||
|
|
pr_warn("failed to free unused decrypted pages\n");
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
free_init_pages("unused decrypted", vaddr, vaddr_end);
|
||
|
|
}
|
||
|
|
|
||
|
|
void __init mem_encrypt_init(void)
|
||
|
|
{
|
||
|
|
if (!sme_me_mask)
|
||
|
|
return;
|
||
|
|
|
||
|
|
/* Call into SWIOTLB to update the SWIOTLB DMA buffers */
|
||
|
|
swiotlb_update_mem_attributes();
|
||
|
|
|
||
|
|
/*
|
||
|
|
* With SEV, DMA operations cannot use encryption, we need to use
|
||
|
|
* SWIOTLB to bounce buffer DMA operation.
|
||
|
|
*/
|
||
|
|
if (sev_active())
|
||
|
|
dma_ops = &swiotlb_dma_ops;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* With SEV, we need to unroll the rep string I/O instructions.
|
||
|
|
*/
|
||
|
|
if (sev_active())
|
||
|
|
static_branch_enable(&sev_enable_key);
|
||
|
|
|
||
|
|
pr_info("AMD %s active\n",
|
||
|
|
sev_active() ? "Secure Encrypted Virtualization (SEV)"
|
||
|
|
: "Secure Memory Encryption (SME)");
|
||
|
|
}
|
||
|
|
|