[dpdk-dev] [PATCH dpdk 5/5] RFC: vfio/ppc64/spapr: Use correct bus addresses for DMA map

[Alexey Kardashevskiy <aik@ozlabs.ru>]

VFIO_IOMMU_SPAPR_TCE_CREATE ioctl() returns the actual bus address for
just created DMA window. It happens to start from zero because the default
window is removed (leaving no windows) and new window starts from zero.
However this is not guaranteed and the new window may start from another
address, this adds an error check.

Another issue is that IOVA passed to VFIO_IOMMU_MAP_DMA should be a PCI
bus address while in this case a physical address of a user page is used.
This changes IOVA to start from zero in a hope that the rest of DPDK
expects this.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
 lib/librte_eal/linuxapp/eal/eal_vfio.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/lib/librte_eal/linuxapp/eal/eal_vfio.c b/lib/librte_eal/linuxapp/eal/eal_vfio.c
index 46f951f4d..8b8e75c4f 100644
--- a/lib/librte_eal/linuxapp/eal/eal_vfio.c
+++ b/lib/librte_eal/linuxapp/eal/eal_vfio.c
@@ -658,7 +658,7 @@ vfio_spapr_dma_map(int vfio_container_fd)
 {
 	const struct rte_memseg *ms = rte_eal_get_physmem_layout();
 	int i, ret;
-
+	phys_addr_t io_offset;
 	struct vfio_iommu_spapr_register_memory reg = {
 		.argsz = sizeof(reg),
 		.flags = 0
@@ -702,6 +702,13 @@ vfio_spapr_dma_map(int vfio_container_fd)
 		return -1;
 	}
 
+	io_offset = create.start_addr;
+	if (io_offset) {
+		RTE_LOG(ERR, EAL, "  DMA offsets other than zero is not supported, "
+				"new window is created at %lx\n", io_offset);
+		return -1;
+	}
+
 	/* map all DPDK segments for DMA. use 1:1 PA to IOVA mapping */
 	for (i = 0; i < RTE_MAX_MEMSEG; i++) {
 		struct vfio_iommu_type1_dma_map dma_map;
@@ -723,7 +730,7 @@ vfio_spapr_dma_map(int vfio_container_fd)
 		dma_map.argsz = sizeof(struct vfio_iommu_type1_dma_map);
 		dma_map.vaddr = ms[i].addr_64;
 		dma_map.size = ms[i].len;
-		dma_map.iova = ms[i].phys_addr;
+		dma_map.iova = io_offset;
 		dma_map.flags = VFIO_DMA_MAP_FLAG_READ |
 				 VFIO_DMA_MAP_FLAG_WRITE;
 
@@ -735,6 +742,7 @@ vfio_spapr_dma_map(int vfio_container_fd)
 			return -1;
 		}
 
+		io_offset += dma_map.size;
 	}
 
 	return 0;
-- 
2.11.0