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x86/mm: Add DMA support for SEV memory encryption

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DMA access to encrypted memory cannot be performed when SEV is active.
In order for DMA to properly work when SEV is active, the SWIOTLB bounce
buffers must be used.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>C
Tested-by: Borislav Petkov <bp@suse.de>
Cc: kvm@vger.kernel.org
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Link: https://lkml.kernel.org/r/20171020143059.3291-12-brijesh.singh@amd.com
This commit is contained in:
Tom Lendacky
2017-10-20 09:30:53 -05:00
committed by Thomas Gleixner
parent 0e4c12b45a
commit d7b417fa08
2 changed files with 89 additions and 2 deletions
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5
lib/swiotlb.c
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@@ -507,8 +507,9 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
if (no_iotlb_memory)
panic("Can not allocate SWIOTLB buffer earlier and can't now provide you with the DMA bounce buffer");
if (sme_active())
pr_warn_once("SME is active and system is using DMA bounce buffers\n");
if (mem_encrypt_active())
pr_warn_once("%s is active and system is using DMA bounce buffers\n",
sme_active() ? "SME" : "SEV");
mask = dma_get_seg_boundary(hwdev);