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![Juergen Gross](/assets/img/avatar_default.png)
Instead of using arch_has_restricted_virtio_memory_access() together with CONFIG_ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS, replace those with platform_has() and a new platform feature PLATFORM_VIRTIO_RESTRICTED_MEM_ACCESS. Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> Tested-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> # Arm64 only Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: Borislav Petkov <bp@suse.de>
530 lines
14 KiB
C
530 lines
14 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* AMD Memory Encryption Support
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*
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* Copyright (C) 2016 Advanced Micro Devices, Inc.
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*
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* Author: Tom Lendacky <thomas.lendacky@amd.com>
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*/
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#define DISABLE_BRANCH_PROFILING
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#include <linux/linkage.h>
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#include <linux/init.h>
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#include <linux/mm.h>
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#include <linux/dma-direct.h>
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#include <linux/swiotlb.h>
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#include <linux/mem_encrypt.h>
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#include <linux/device.h>
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#include <linux/kernel.h>
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#include <linux/bitops.h>
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#include <linux/dma-mapping.h>
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#include <linux/virtio_config.h>
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#include <linux/cc_platform.h>
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#include <linux/platform-feature.h>
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#include <asm/tlbflush.h>
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#include <asm/fixmap.h>
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#include <asm/setup.h>
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#include <asm/bootparam.h>
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#include <asm/set_memory.h>
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#include <asm/cacheflush.h>
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#include <asm/processor-flags.h>
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#include <asm/msr.h>
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#include <asm/cmdline.h>
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#include <asm/sev.h>
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#include "mm_internal.h"
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/*
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* Since SME related variables are set early in the boot process they must
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* reside in the .data section so as not to be zeroed out when the .bss
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* section is later cleared.
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*/
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u64 sme_me_mask __section(".data") = 0;
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u64 sev_status __section(".data") = 0;
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u64 sev_check_data __section(".data") = 0;
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EXPORT_SYMBOL(sme_me_mask);
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/* Buffer used for early in-place encryption by BSP, no locking needed */
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static char sme_early_buffer[PAGE_SIZE] __initdata __aligned(PAGE_SIZE);
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/*
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* SNP-specific routine which needs to additionally change the page state from
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* private to shared before copying the data from the source to destination and
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* restore after the copy.
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*/
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static inline void __init snp_memcpy(void *dst, void *src, size_t sz,
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unsigned long paddr, bool decrypt)
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{
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unsigned long npages = PAGE_ALIGN(sz) >> PAGE_SHIFT;
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if (decrypt) {
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/*
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* @paddr needs to be accessed decrypted, mark the page shared in
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* the RMP table before copying it.
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*/
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early_snp_set_memory_shared((unsigned long)__va(paddr), paddr, npages);
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memcpy(dst, src, sz);
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/* Restore the page state after the memcpy. */
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early_snp_set_memory_private((unsigned long)__va(paddr), paddr, npages);
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} else {
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/*
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* @paddr need to be accessed encrypted, no need for the page state
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* change.
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*/
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memcpy(dst, src, sz);
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}
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}
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/*
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* This routine does not change the underlying encryption setting of the
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* page(s) that map this memory. It assumes that eventually the memory is
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* meant to be accessed as either encrypted or decrypted but the contents
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* are currently not in the desired state.
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*
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* This routine follows the steps outlined in the AMD64 Architecture
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* Programmer's Manual Volume 2, Section 7.10.8 Encrypt-in-Place.
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*/
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static void __init __sme_early_enc_dec(resource_size_t paddr,
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unsigned long size, bool enc)
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{
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void *src, *dst;
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size_t len;
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if (!sme_me_mask)
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return;
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wbinvd();
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/*
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* There are limited number of early mapping slots, so map (at most)
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* one page at time.
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*/
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while (size) {
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len = min_t(size_t, sizeof(sme_early_buffer), size);
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/*
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* Create mappings for the current and desired format of
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* the memory. Use a write-protected mapping for the source.
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*/
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src = enc ? early_memremap_decrypted_wp(paddr, len) :
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early_memremap_encrypted_wp(paddr, len);
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dst = enc ? early_memremap_encrypted(paddr, len) :
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early_memremap_decrypted(paddr, len);
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/*
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* If a mapping can't be obtained to perform the operation,
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* then eventual access of that area in the desired mode
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* will cause a crash.
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*/
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BUG_ON(!src || !dst);
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/*
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* Use a temporary buffer, of cache-line multiple size, to
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* avoid data corruption as documented in the APM.
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*/
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if (cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) {
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snp_memcpy(sme_early_buffer, src, len, paddr, enc);
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snp_memcpy(dst, sme_early_buffer, len, paddr, !enc);
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} else {
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memcpy(sme_early_buffer, src, len);
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memcpy(dst, sme_early_buffer, len);
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}
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early_memunmap(dst, len);
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early_memunmap(src, len);
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paddr += len;
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size -= len;
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}
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}
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void __init sme_early_encrypt(resource_size_t paddr, unsigned long size)
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{
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__sme_early_enc_dec(paddr, size, true);
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}
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void __init sme_early_decrypt(resource_size_t paddr, unsigned long size)
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{
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__sme_early_enc_dec(paddr, size, false);
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}
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static void __init __sme_early_map_unmap_mem(void *vaddr, unsigned long size,
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bool map)
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{
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unsigned long paddr = (unsigned long)vaddr - __PAGE_OFFSET;
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pmdval_t pmd_flags, pmd;
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/* Use early_pmd_flags but remove the encryption mask */
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pmd_flags = __sme_clr(early_pmd_flags);
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do {
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pmd = map ? (paddr & PMD_MASK) + pmd_flags : 0;
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__early_make_pgtable((unsigned long)vaddr, pmd);
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vaddr += PMD_SIZE;
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paddr += PMD_SIZE;
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size = (size <= PMD_SIZE) ? 0 : size - PMD_SIZE;
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} while (size);
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flush_tlb_local();
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}
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void __init sme_unmap_bootdata(char *real_mode_data)
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{
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struct boot_params *boot_data;
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unsigned long cmdline_paddr;
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if (!cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT))
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return;
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/* Get the command line address before unmapping the real_mode_data */
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boot_data = (struct boot_params *)real_mode_data;
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cmdline_paddr = boot_data->hdr.cmd_line_ptr | ((u64)boot_data->ext_cmd_line_ptr << 32);
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__sme_early_map_unmap_mem(real_mode_data, sizeof(boot_params), false);
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if (!cmdline_paddr)
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return;
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__sme_early_map_unmap_mem(__va(cmdline_paddr), COMMAND_LINE_SIZE, false);
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}
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void __init sme_map_bootdata(char *real_mode_data)
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{
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struct boot_params *boot_data;
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unsigned long cmdline_paddr;
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if (!cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT))
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return;
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__sme_early_map_unmap_mem(real_mode_data, sizeof(boot_params), true);
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/* Get the command line address after mapping the real_mode_data */
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boot_data = (struct boot_params *)real_mode_data;
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cmdline_paddr = boot_data->hdr.cmd_line_ptr | ((u64)boot_data->ext_cmd_line_ptr << 32);
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if (!cmdline_paddr)
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return;
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__sme_early_map_unmap_mem(__va(cmdline_paddr), COMMAND_LINE_SIZE, true);
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}
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void __init sev_setup_arch(void)
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{
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phys_addr_t total_mem = memblock_phys_mem_size();
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unsigned long size;
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if (!cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT))
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return;
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/*
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* For SEV, all DMA has to occur via shared/unencrypted pages.
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* SEV uses SWIOTLB to make this happen without changing device
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* drivers. However, depending on the workload being run, the
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* default 64MB of SWIOTLB may not be enough and SWIOTLB may
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* run out of buffers for DMA, resulting in I/O errors and/or
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* performance degradation especially with high I/O workloads.
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*
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* Adjust the default size of SWIOTLB for SEV guests using
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* a percentage of guest memory for SWIOTLB buffers.
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* Also, as the SWIOTLB bounce buffer memory is allocated
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* from low memory, ensure that the adjusted size is within
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* the limits of low available memory.
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*
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* The percentage of guest memory used here for SWIOTLB buffers
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* is more of an approximation of the static adjustment which
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* 64MB for <1G, and ~128M to 256M for 1G-to-4G, i.e., the 6%
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*/
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size = total_mem * 6 / 100;
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size = clamp_val(size, IO_TLB_DEFAULT_SIZE, SZ_1G);
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swiotlb_adjust_size(size);
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/* Set restricted memory access for virtio. */
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platform_set(PLATFORM_VIRTIO_RESTRICTED_MEM_ACCESS);
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}
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static unsigned long pg_level_to_pfn(int level, pte_t *kpte, pgprot_t *ret_prot)
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{
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unsigned long pfn = 0;
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pgprot_t prot;
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switch (level) {
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case PG_LEVEL_4K:
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pfn = pte_pfn(*kpte);
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prot = pte_pgprot(*kpte);
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break;
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case PG_LEVEL_2M:
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pfn = pmd_pfn(*(pmd_t *)kpte);
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prot = pmd_pgprot(*(pmd_t *)kpte);
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break;
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case PG_LEVEL_1G:
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pfn = pud_pfn(*(pud_t *)kpte);
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prot = pud_pgprot(*(pud_t *)kpte);
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break;
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default:
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WARN_ONCE(1, "Invalid level for kpte\n");
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return 0;
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}
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if (ret_prot)
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*ret_prot = prot;
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return pfn;
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}
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static bool amd_enc_tlb_flush_required(bool enc)
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{
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return true;
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}
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static bool amd_enc_cache_flush_required(void)
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{
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return !cpu_feature_enabled(X86_FEATURE_SME_COHERENT);
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}
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static void enc_dec_hypercall(unsigned long vaddr, int npages, bool enc)
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{
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#ifdef CONFIG_PARAVIRT
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unsigned long sz = npages << PAGE_SHIFT;
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unsigned long vaddr_end = vaddr + sz;
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while (vaddr < vaddr_end) {
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int psize, pmask, level;
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unsigned long pfn;
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pte_t *kpte;
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kpte = lookup_address(vaddr, &level);
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if (!kpte || pte_none(*kpte)) {
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WARN_ONCE(1, "kpte lookup for vaddr\n");
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return;
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}
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pfn = pg_level_to_pfn(level, kpte, NULL);
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if (!pfn)
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continue;
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psize = page_level_size(level);
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pmask = page_level_mask(level);
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notify_page_enc_status_changed(pfn, psize >> PAGE_SHIFT, enc);
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vaddr = (vaddr & pmask) + psize;
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}
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#endif
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}
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static void amd_enc_status_change_prepare(unsigned long vaddr, int npages, bool enc)
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{
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/*
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* To maintain the security guarantees of SEV-SNP guests, make sure
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* to invalidate the memory before encryption attribute is cleared.
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*/
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if (cc_platform_has(CC_ATTR_GUEST_SEV_SNP) && !enc)
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snp_set_memory_shared(vaddr, npages);
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}
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/* Return true unconditionally: return value doesn't matter for the SEV side */
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static bool amd_enc_status_change_finish(unsigned long vaddr, int npages, bool enc)
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{
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/*
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* After memory is mapped encrypted in the page table, validate it
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* so that it is consistent with the page table updates.
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*/
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if (cc_platform_has(CC_ATTR_GUEST_SEV_SNP) && enc)
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snp_set_memory_private(vaddr, npages);
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if (!cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT))
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enc_dec_hypercall(vaddr, npages, enc);
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return true;
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}
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static void __init __set_clr_pte_enc(pte_t *kpte, int level, bool enc)
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{
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pgprot_t old_prot, new_prot;
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unsigned long pfn, pa, size;
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pte_t new_pte;
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pfn = pg_level_to_pfn(level, kpte, &old_prot);
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if (!pfn)
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return;
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new_prot = old_prot;
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if (enc)
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pgprot_val(new_prot) |= _PAGE_ENC;
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else
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pgprot_val(new_prot) &= ~_PAGE_ENC;
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/* If prot is same then do nothing. */
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if (pgprot_val(old_prot) == pgprot_val(new_prot))
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return;
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pa = pfn << PAGE_SHIFT;
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size = page_level_size(level);
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/*
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* We are going to perform in-place en-/decryption and change the
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* physical page attribute from C=1 to C=0 or vice versa. Flush the
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* caches to ensure that data gets accessed with the correct C-bit.
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*/
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clflush_cache_range(__va(pa), size);
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/* Encrypt/decrypt the contents in-place */
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if (enc) {
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sme_early_encrypt(pa, size);
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} else {
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sme_early_decrypt(pa, size);
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/*
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* ON SNP, the page state in the RMP table must happen
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* before the page table updates.
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*/
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early_snp_set_memory_shared((unsigned long)__va(pa), pa, 1);
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}
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/* Change the page encryption mask. */
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new_pte = pfn_pte(pfn, new_prot);
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set_pte_atomic(kpte, new_pte);
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/*
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* If page is set encrypted in the page table, then update the RMP table to
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* add this page as private.
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*/
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if (enc)
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early_snp_set_memory_private((unsigned long)__va(pa), pa, 1);
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}
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static int __init early_set_memory_enc_dec(unsigned long vaddr,
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unsigned long size, bool enc)
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{
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unsigned long vaddr_end, vaddr_next, start;
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unsigned long psize, pmask;
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int split_page_size_mask;
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int level, ret;
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pte_t *kpte;
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start = vaddr;
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vaddr_next = vaddr;
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vaddr_end = vaddr + size;
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for (; vaddr < vaddr_end; vaddr = vaddr_next) {
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kpte = lookup_address(vaddr, &level);
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if (!kpte || pte_none(*kpte)) {
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ret = 1;
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goto out;
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}
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if (level == PG_LEVEL_4K) {
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__set_clr_pte_enc(kpte, level, enc);
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vaddr_next = (vaddr & PAGE_MASK) + PAGE_SIZE;
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continue;
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}
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psize = page_level_size(level);
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pmask = page_level_mask(level);
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/*
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* Check whether we can change the large page in one go.
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* We request a split when the address is not aligned and
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* the number of pages to set/clear encryption bit is smaller
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* than the number of pages in the large page.
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*/
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if (vaddr == (vaddr & pmask) &&
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((vaddr_end - vaddr) >= psize)) {
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__set_clr_pte_enc(kpte, level, enc);
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vaddr_next = (vaddr & pmask) + psize;
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continue;
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}
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/*
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* The virtual address is part of a larger page, create the next
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* level page table mapping (4K or 2M). If it is part of a 2M
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* page then we request a split of the large page into 4K
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* chunks. A 1GB large page is split into 2M pages, resp.
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*/
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if (level == PG_LEVEL_2M)
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split_page_size_mask = 0;
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else
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split_page_size_mask = 1 << PG_LEVEL_2M;
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/*
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* kernel_physical_mapping_change() does not flush the TLBs, so
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* a TLB flush is required after we exit from the for loop.
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*/
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kernel_physical_mapping_change(__pa(vaddr & pmask),
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__pa((vaddr_end & pmask) + psize),
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split_page_size_mask);
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}
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ret = 0;
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early_set_mem_enc_dec_hypercall(start, PAGE_ALIGN(size) >> PAGE_SHIFT, enc);
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out:
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__flush_tlb_all();
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return ret;
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}
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int __init early_set_memory_decrypted(unsigned long vaddr, unsigned long size)
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{
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return early_set_memory_enc_dec(vaddr, size, false);
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}
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int __init early_set_memory_encrypted(unsigned long vaddr, unsigned long size)
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{
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return early_set_memory_enc_dec(vaddr, size, true);
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}
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void __init early_set_mem_enc_dec_hypercall(unsigned long vaddr, int npages, bool enc)
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{
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enc_dec_hypercall(vaddr, npages, enc);
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}
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void __init sme_early_init(void)
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{
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unsigned int i;
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if (!sme_me_mask)
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return;
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early_pmd_flags = __sme_set(early_pmd_flags);
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__supported_pte_mask = __sme_set(__supported_pte_mask);
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/* Update the protection map with memory encryption mask */
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for (i = 0; i < ARRAY_SIZE(protection_map); i++)
|
|
protection_map[i] = pgprot_encrypted(protection_map[i]);
|
|
|
|
x86_platform.guest.enc_status_change_prepare = amd_enc_status_change_prepare;
|
|
x86_platform.guest.enc_status_change_finish = amd_enc_status_change_finish;
|
|
x86_platform.guest.enc_tlb_flush_required = amd_enc_tlb_flush_required;
|
|
x86_platform.guest.enc_cache_flush_required = amd_enc_cache_flush_required;
|
|
}
|
|
|
|
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 (cc_platform_has(CC_ATTR_MEM_ENCRYPT)) {
|
|
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);
|
|
}
|