OpenCloudOS-Kernel/arch/x86/mm/mem_encrypt.c

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x86/sev: Move common memory encryption code to mem_encrypt.c SEV and TDX both protect guest memory from host accesses. They both use guest physical address bits to communicate to the hardware which pages receive protection or not. SEV and TDX both assume that all I/O (real devices and virtio) must be performed to pages *without* protection. To add this support, AMD SEV code forces force_dma_unencrypted() to decrypt DMA pages when DMA pages were allocated for I/O. It also uses swiotlb_update_mem_attributes() to update decryption bits in SWIOTLB DMA buffers. Since TDX also uses a similar memory sharing design, all the above mentioned changes can be reused. So move force_dma_unencrypted(), SWIOTLB update code and virtio changes out of mem_encrypt_amd.c to mem_encrypt.c. Introduce a new config option X86_MEM_ENCRYPT that can be selected by platforms which use x86 memory encryption features (needed in both AMD SEV and Intel TDX guest platforms). Since the code is moved from mem_encrypt_amd.c, inherit the same make flags. This is preparation for enabling TDX memory encryption support and it has no functional changes. Co-developed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Andi Kleen <ak@linux.intel.com> Reviewed-by: Tony Luck <tony.luck@intel.com> Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com> Tested-by: Tom Lendacky <thomas.lendacky@amd.com> Link: https://lore.kernel.org/r/20211206135505.75045-4-kirill.shutemov@linux.intel.com
2021-12-06 21:55:05 +08:00
// SPDX-License-Identifier: GPL-2.0-only
/*
* Memory Encryption Support Common Code
*
* Copyright (C) 2016 Advanced Micro Devices, Inc.
*
* Author: Tom Lendacky <thomas.lendacky@amd.com>
*/
#include <linux/dma-direct.h>
#include <linux/dma-mapping.h>
#include <linux/swiotlb.h>
#include <linux/cc_platform.h>
#include <linux/mem_encrypt.h>
/* Override for DMA direct allocation check - ARCH_HAS_FORCE_DMA_UNENCRYPTED */
bool force_dma_unencrypted(struct device *dev)
{
/*
* For SEV, all DMA must be to unencrypted addresses.
*/
if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT))
return true;
/*
* For SME, all DMA must be to unencrypted addresses if the
* device does not support DMA to addresses that include the
* encryption mask.
*/
if (cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT)) {
u64 dma_enc_mask = DMA_BIT_MASK(__ffs64(sme_me_mask));
u64 dma_dev_mask = min_not_zero(dev->coherent_dma_mask,
dev->bus_dma_limit);
if (dma_dev_mask <= dma_enc_mask)
return true;
}
return false;
}
static void print_mem_encrypt_feature_info(void)
{
x86/mm: Make DMA memory shared for TD guest Intel TDX doesn't allow VMM to directly access guest private memory. Any memory that is required for communication with the VMM must be shared explicitly. The same rule applies for any DMA to and from the TDX guest. All DMA pages have to be marked as shared pages. A generic way to achieve this without any changes to device drivers is to use the SWIOTLB framework. The previous patch ("Add support for TDX shared memory") gave TDX guests the _ability_ to make some pages shared, but did not make any pages shared. This actually marks SWIOTLB buffers *as* shared. Start returning true for cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT) in TDX guests. This has several implications: - Allows the existing mem_encrypt_init() to be used for TDX which sets SWIOTLB buffers shared (aka. "decrypted"). - Ensures that all DMA is routed via the SWIOTLB mechanism (see pci_swiotlb_detect()) Stop selecting DYNAMIC_PHYSICAL_MASK directly. It will get set indirectly by selecting X86_MEM_ENCRYPT. mem_encrypt_init() is currently under an AMD-specific #ifdef. Move it to a generic area of the header. Co-developed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Andi Kleen <ak@linux.intel.com> Reviewed-by: Tony Luck <tony.luck@intel.com> Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com> Link: https://lkml.kernel.org/r/20220405232939.73860-28-kirill.shutemov@linux.intel.com
2022-04-06 07:29:36 +08:00
pr_info("Memory Encryption Features active:");
if (cpu_feature_enabled(X86_FEATURE_TDX_GUEST)) {
pr_cont(" Intel TDX\n");
return;
}
pr_cont(" AMD");
x86/sev: Move common memory encryption code to mem_encrypt.c SEV and TDX both protect guest memory from host accesses. They both use guest physical address bits to communicate to the hardware which pages receive protection or not. SEV and TDX both assume that all I/O (real devices and virtio) must be performed to pages *without* protection. To add this support, AMD SEV code forces force_dma_unencrypted() to decrypt DMA pages when DMA pages were allocated for I/O. It also uses swiotlb_update_mem_attributes() to update decryption bits in SWIOTLB DMA buffers. Since TDX also uses a similar memory sharing design, all the above mentioned changes can be reused. So move force_dma_unencrypted(), SWIOTLB update code and virtio changes out of mem_encrypt_amd.c to mem_encrypt.c. Introduce a new config option X86_MEM_ENCRYPT that can be selected by platforms which use x86 memory encryption features (needed in both AMD SEV and Intel TDX guest platforms). Since the code is moved from mem_encrypt_amd.c, inherit the same make flags. This is preparation for enabling TDX memory encryption support and it has no functional changes. Co-developed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Andi Kleen <ak@linux.intel.com> Reviewed-by: Tony Luck <tony.luck@intel.com> Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com> Tested-by: Tom Lendacky <thomas.lendacky@amd.com> Link: https://lore.kernel.org/r/20211206135505.75045-4-kirill.shutemov@linux.intel.com
2021-12-06 21:55:05 +08:00
/* Secure Memory Encryption */
if (cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT)) {
/*
* SME is mutually exclusive with any of the SEV
* features below.
*/
pr_cont(" SME\n");
return;
}
/* Secure Encrypted Virtualization */
if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT))
pr_cont(" SEV");
/* Encrypted Register State */
if (cc_platform_has(CC_ATTR_GUEST_STATE_ENCRYPT))
pr_cont(" SEV-ES");
/* Secure Nested Paging */
if (cc_platform_has(CC_ATTR_GUEST_SEV_SNP))
pr_cont(" SEV-SNP");
x86/sev: Move common memory encryption code to mem_encrypt.c SEV and TDX both protect guest memory from host accesses. They both use guest physical address bits to communicate to the hardware which pages receive protection or not. SEV and TDX both assume that all I/O (real devices and virtio) must be performed to pages *without* protection. To add this support, AMD SEV code forces force_dma_unencrypted() to decrypt DMA pages when DMA pages were allocated for I/O. It also uses swiotlb_update_mem_attributes() to update decryption bits in SWIOTLB DMA buffers. Since TDX also uses a similar memory sharing design, all the above mentioned changes can be reused. So move force_dma_unencrypted(), SWIOTLB update code and virtio changes out of mem_encrypt_amd.c to mem_encrypt.c. Introduce a new config option X86_MEM_ENCRYPT that can be selected by platforms which use x86 memory encryption features (needed in both AMD SEV and Intel TDX guest platforms). Since the code is moved from mem_encrypt_amd.c, inherit the same make flags. This is preparation for enabling TDX memory encryption support and it has no functional changes. Co-developed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Andi Kleen <ak@linux.intel.com> Reviewed-by: Tony Luck <tony.luck@intel.com> Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com> Tested-by: Tom Lendacky <thomas.lendacky@amd.com> Link: https://lore.kernel.org/r/20211206135505.75045-4-kirill.shutemov@linux.intel.com
2021-12-06 21:55:05 +08:00
pr_cont("\n");
}
/* Architecture __weak replacement functions */
void __init mem_encrypt_init(void)
{
if (!cc_platform_has(CC_ATTR_MEM_ENCRYPT))
return;
/* Call into SWIOTLB to update the SWIOTLB DMA buffers */
swiotlb_update_mem_attributes();
print_mem_encrypt_feature_info();
}