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authorLogan Gunthorpe <logang@deltatee.com>2019-06-19 12:56:26 -0600
committerBjorn Helgaas <bhelgaas@google.com>2019-06-19 16:43:42 -0500
commit6dbbd053e6aea827abde89ac9b9d6855dab1a66b (patch)
tree22cc773a03637c7d72351c53d2306dc764f5e57a
parenta188339ca5a396acc588e5851ed7e19f66b0ebd9 (diff)
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PCI/P2PDMA: Ignore root complex whitelist when an IOMMU is present
Presently, there is no path to DMA map P2PDMA memory, so if a TLP targeting this memory hits the root complex and an IOMMU is present, the IOMMU will reject the transaction, even if the RC would support P2PDMA. So until the kernel knows to map these DMA addresses in the IOMMU, we should not enable the whitelist when an IOMMU is present. Link: https://lore.kernel.org/linux-pci/20190522201252.2997-1-logang@deltatee.com/ Fixes: 0f97da831026 ("PCI/P2PDMA: Allow P2P DMA between any devices under AMD ZEN Root Complex") Signed-off-by: Logan Gunthorpe <logang@deltatee.com> Reviewed-by: Christian K├Ânig <christian.koenig@amd.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Cc: Christoph Hellwig <hch@lst.de>
-rw-r--r--drivers/pci/p2pdma.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c
index 742928d0053e..84ba3058eada 100644
--- a/drivers/pci/p2pdma.c
+++ b/drivers/pci/p2pdma.c
@@ -18,6 +18,7 @@
#include <linux/percpu-refcount.h>
#include <linux/random.h>
#include <linux/seq_buf.h>
+#include <linux/iommu.h>
struct pci_p2pdma {
struct percpu_ref devmap_ref;
@@ -284,6 +285,9 @@ static bool root_complex_whitelist(struct pci_dev *dev)
struct pci_dev *root = pci_get_slot(host->bus, PCI_DEVFN(0, 0));
unsigned short vendor, device;
+ if (iommu_present(dev->dev.bus))
+ return false;
+
if (!root)
return false;