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Subject[PATCH 2/2] iommu/dma: Avoid SAC address trick for PCIe devices
Date
As for the intel-iommu implementation, relegate the opportunistic
attempt to allocate a SAC address to the domain of conventional PCI
devices only, to avoid it increasingly causing far more performance
issues than possible benefits on modern PCI Express systems.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
---
drivers/iommu/dma-iommu.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 4959f5df21bd..0ff124f16ad4 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -426,7 +426,8 @@ static dma_addr_t iommu_dma_alloc_iova(struct iommu_domain *domain,
dma_limit = min(dma_limit, (u64)domain->geometry.aperture_end);

/* Try to get PCI devices a SAC address */
- if (dma_limit > DMA_BIT_MASK(32) && dev_is_pci(dev))
+ if (dma_limit > DMA_BIT_MASK(32) &&
+ dev_is_pci(dev) && !pci_is_pcie(to_pci_dev(dev)))
iova = alloc_iova_fast(iovad, iova_len,
DMA_BIT_MASK(32) >> shift, false);

--
2.23.0.dirty
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