diff options
authorRonny Hegewald <>2012-08-31 09:57:52 +0000
committerGreg Kroah-Hartman <>2012-09-14 10:00:33 -0700
commit095ac020be339cad6f158508cc3b9f740c60b53a (patch)
parent9db2bc1e0363bb9401e6407b198463c01f32dd84 (diff)
xen: Use correct masking in xen_swiotlb_alloc_coherent.
commit b5031ed1be0aa419250557123633453753181643 upstream. When running 32-bit pvops-dom0 and a driver tries to allocate a coherent DMA-memory the xen swiotlb-implementation returned memory beyond 4GB. The underlaying reason is that if the supplied driver passes in a DMA_BIT_MASK(64) ( hwdev->coherent_dma_mask is set to 0xffffffffffffffff) our dma_mask will be u64 set to 0xffffffffffffffff even if we set it to DMA_BIT_MASK(32) previously. Meaning we do not reset the upper bits. By using the dma_alloc_coherent_mask function - it does the proper casting and we get 0xfffffffff. This caused not working sound on a system with 4 GB and a 64-bit compatible sound-card with sets the DMA-mask to 64bit. On bare-metal and the forward-ported xen-dom0 patches from OpenSuse a coherent DMA-memory is always allocated inside the 32-bit address-range by calling dma_alloc_coherent_mask. This patch adds the same functionality to xen swiotlb and is a rebase of the original patch from Ronny Hegewald which never got upstream b/c the underlaying reason was not understood until now. The original email with the original patch is in: the original thread from where the discussion started is in: Signed-off-by: Ronny Hegewald <> Signed-off-by: Stefano Panella <> Acked-By: David Vrabel <> Signed-off-by: Konrad Rzeszutek Wilk <> Signed-off-by: Greg Kroah-Hartman <>
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index 1afb4fba11b..4d519488d30 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -232,7 +232,7 @@ xen_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
return ret;
if (hwdev && hwdev->coherent_dma_mask)
- dma_mask = hwdev->coherent_dma_mask;
+ dma_mask = dma_alloc_coherent_mask(hwdev, flags);
phys = virt_to_phys(ret);
dev_addr = xen_phys_to_bus(phys);