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authorTom Lendacky <thomas.lendacky@amd.com>2017-10-06 16:35:40 -0500
committerJoerg Roedel <jroedel@suse.de>2017-10-10 19:49:30 +0200
commitaba2d9a6385a5cc4f7a7e8eb5788e1ddbc213fc0 (patch)
tree6cfb500a8efede70d0f23bfa6de5364547afd41d
parent8a5776a5f49812d29fe4b2d0a2d71675c3facf3f (diff)
iommu/amd: Do not disable SWIOTLB if SME is active
When SME memory encryption is active it will rely on SWIOTLB to handle DMA for devices that cannot support the addressing requirements of having the encryption mask set in the physical address. The IOMMU currently disables SWIOTLB if it is not running in passthrough mode. This is not desired as non-PCI devices attempting DMA may fail. Update the code to check if SME is active and not disable SWIOTLB. Fixes: 2543a786aa25 ("iommu/amd: Allow the AMD IOMMU to work with memory encryption") Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> Signed-off-by: Joerg Roedel <jroedel@suse.de>
-rw-r--r--drivers/iommu/amd_iommu.c10
1 files changed, 6 insertions, 4 deletions
diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 51f8215877f5..822679ac90a1 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -2773,14 +2773,16 @@ int __init amd_iommu_init_api(void)
int __init amd_iommu_init_dma_ops(void)
{
- swiotlb = iommu_pass_through ? 1 : 0;
+ swiotlb = (iommu_pass_through || sme_me_mask) ? 1 : 0;
iommu_detected = 1;
/*
* In case we don't initialize SWIOTLB (actually the common case
- * when AMD IOMMU is enabled), make sure there are global
- * dma_ops set as a fall-back for devices not handled by this
- * driver (for example non-PCI devices).
+ * when AMD IOMMU is enabled and SME is not active), make sure there
+ * are global dma_ops set as a fall-back for devices not handled by
+ * this driver (for example non-PCI devices). When SME is active,
+ * make sure that swiotlb variable remains set so the global dma_ops
+ * continue to be SWIOTLB.
*/
if (!swiotlb)
dma_ops = &nommu_dma_ops;