be2net: enable IOMMU pass through for be2net

This patch sets the coherent DMA mask to 64-bit after the be2net driver has
been acknowledged that the system is 64-bit DMA capable. The coherent DMA
mask is examined by the Intel IOMMU driver to determine whether to allow
pass through context mapping for all devices. With this patch, the be2net
driver combined with be2net compatible hardware provides comparable
performance to the case where vt-d is disabled. The main use-case for this
change is to decrease the time necessary to copy virtual machine memory
during KVM live migration instantiations.

This patch was tested on a system that enables the IOMMU in non-coherent
mode. Two DMA remapper issues were encountered in the previous version and
both patches have been committed.
    commit f6af0cba92a8be38e9fe66c73884bce5860c17d6
    commit 36042fab6e41dbcb03a026c94117a5c49c1bab69

Signed-off-by: Craig Hada <craig.hada@hp.com>
Signed-off-by: Sathya Perla <sathya.perla@emulex.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/emulex/benet/be_main.c b/drivers/net/ethernet/emulex/benet/be_main.c
index e773fbaf8d02480865e7f15318996a365f8490b5..21808680b91fb3b8e238b9be5d3bcf34096eeacc 100644 (file)
--- a/drivers/net/ethernet/emulex/benet/be_main.c
+++ b/drivers/net/ethernet/emulex/benet/be_main.c
@@ -4134,6 +4134,11 @@ static int be_probe(struct pci_dev *pdev, const struct pci_device_id *pdev_id)
 
        status = dma_set_mask(&pdev->dev, DMA_BIT_MASK(64));
        if (!status) {
+               status = dma_set_coherent_mask(&pdev->dev, DMA_BIT_MASK(64));
+               if (status < 0) {
+                       dev_err(&pdev->dev, "dma_set_coherent_mask failed\n");
+                       goto free_netdev;
+               }
                netdev->features |= NETIF_F_HIGHDMA;
        } else {
                status = dma_set_mask(&pdev->dev, DMA_BIT_MASK(32));