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// 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>
#include <linux/virtio_config.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)
{
pr_info("AMD Memory Encryption Features active:");
/* 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");
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();
}
int arch_has_restricted_virtio_memory_access(void)
{
return cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT);
}
EXPORT_SYMBOL_GPL(arch_has_restricted_virtio_memory_access);
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