[PATCH v4 07/15] vfio/common: Track whether DMA Translation is enabled on the vIOMMU

[Joao Martins]

vfio_get_group() allocates and fills the group/container/space on
success which will store the AddressSpace inside the VFIOSpace struct.
Use the newly added pci_device_iommu_get_attr() to see if DMA
translation is enabled or not. Assume that by default it is enabled.

Today, this means only intel-iommu supports it.

Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
---
 include/hw/vfio/vfio-common.h |  1 +
 hw/vfio/pci.c                 | 15 ++++++++++++++-
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
index eed244f25f34..f41860988d6b 100644
--- a/include/hw/vfio/vfio-common.h
+++ b/include/hw/vfio/vfio-common.h
@@ -70,6 +70,7 @@ typedef struct VFIOMigration {
 
 typedef struct VFIOAddressSpace {
     AddressSpace *as;
+    bool no_dma_translation;
     QLIST_HEAD(, VFIOContainer) containers;
     QLIST_ENTRY(VFIOAddressSpace) list;
 } VFIOAddressSpace;
diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index 73874a94de12..8a98e6ffc480 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -2900,6 +2900,7 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
     VFIOPCIDevice *vdev = VFIO_PCI(pdev);
     VFIODevice *vbasedev = &vdev->vbasedev;
     VFIODevice *vbasedev_iter;
+    VFIOAddressSpace *space;
     VFIOGroup *group;
     char *tmp, *subsys, group_path[PATH_MAX], *group_name;
     Error *err = NULL;
@@ -2907,7 +2908,7 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
     struct stat st;
     int groupid;
     int i, ret;
-    bool is_mdev;
+    bool is_mdev, dma_translation;
     char uuid[UUID_FMT_LEN];
     char *name;
 
@@ -2961,6 +2962,18 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
         goto error;
     }
 
+    space = group->container->space;
+
+    /*
+     * Support for toggling DMA translation is optional.
+     * By default, DMA translation is assumed to be enabled i.e.
+     * space::no_dma_translation is 0.
+     */
+    dma_translation = true;
+    pci_device_iommu_get_attr(pdev, IOMMU_ATTR_DMA_TRANSLATION,
+                              &dma_translation);
+    space->no_dma_translation = !dma_translation;
+
     QLIST_FOREACH(vbasedev_iter, &group->device_list, next) {
         if (strcmp(vbasedev_iter->name, vbasedev->name) == 0) {
             error_setg(errp, "device is already attached");
-- 
2.17.2