[Qemu-devel] [PATCH v9 4/4] vfio: Enable for SPAPR

[Alexey Kardashevskiy <aik@ozlabs.ru>]

This turns the sPAPR support on and enables VFIO container use
in the kernel.

This extends vfio_connect_container to support VFIO_SPAPR_TCE_IOMMU type
in the host kernel.

This registers a memory listener which sPAPR IOMMU will notify when
executing H_PUT_TCE/etc DMA calls. The listener then will notify the host
kernel about DMA map/unmap operation via VFIO_IOMMU_MAP_DMA/
VFIO_IOMMU_UNMAP_DMA ioctls.

This executes VFIO_IOMMU_ENABLE ioctl to make sure that the IOMMU is free
of mappings and can be exclusively given to the user. At the moment SPAPR
is the only platform requiring this call to be implemented.

Note that the host kernel function implementing VFIO_IOMMU_DISABLE
is called automatically when container's fd is closed so there is
no need to call it explicitly from QEMU. We may need to call
VFIO_IOMMU_DISABLE explicitly in the future for some sort of dynamic
reconfiguration (PCI hotplug or dynamic IOMMU group management).

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
Changes:
v9:
* vfio_container_ioctl() checks for @req now
* fixed commit log and added a comment about implicit call of VFIO_IOMMU_DISABLE

v8:
* added note about VFIO_IOMMU_DISABLE in the commit log

v7:
* added more details in commit log

v5:
* multiple returns converted to gotos

v4:
* fixed format string to use %m which is a glibc extension:
"Print output of strerror(errno). No argument is required."
---
 hw/misc/vfio.c | 36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/hw/misc/vfio.c b/hw/misc/vfio.c
index bdd6e33..7b279c4 100644
--- a/hw/misc/vfio.c
+++ b/hw/misc/vfio.c
@@ -3650,6 +3650,39 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as)
 
         container->iommu_data.type1.initialized = true;
 
+    } else if (ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_SPAPR_TCE_IOMMU)) {
+        ret = ioctl(group->fd, VFIO_GROUP_SET_CONTAINER, &fd);
+        if (ret) {
+            error_report("vfio: failed to set group container: %m");
+            ret = -errno;
+            goto free_container_exit;
+        }
+
+        ret = ioctl(fd, VFIO_SET_IOMMU, VFIO_SPAPR_TCE_IOMMU);
+        if (ret) {
+            error_report("vfio: failed to set iommu for container: %m");
+            ret = -errno;
+            goto free_container_exit;
+        }
+
+        /*
+         * The host kernel code implementing VFIO_IOMMU_DISABLE is called
+         * when container fd is closed so we do not call it explicitly
+         * in this file.
+         */
+        ret = ioctl(fd, VFIO_IOMMU_ENABLE);
+        if (ret) {
+            error_report("vfio: failed to enable container: %m");
+            ret = -errno;
+            goto free_container_exit;
+        }
+
+        container->iommu_data.type1.listener = vfio_memory_listener;
+        container->iommu_data.release = vfio_listener_release;
+
+        memory_listener_register(&container->iommu_data.type1.listener,
+                                 container->space->as);
+
     } else {
         error_report("vfio: No available IOMMU models");
         ret = -EINVAL;
@@ -4352,6 +4385,9 @@ int vfio_container_ioctl(AddressSpace *as, int32_t groupid,
 {
     /* We allow only certain ioctls to the container */
     switch (req) {
+    case VFIO_CHECK_EXTENSION:
+    case VFIO_IOMMU_SPAPR_TCE_GET_INFO:
+        break;
     default:
         /* Return an error on unknown requests */
         error_report("vfio: unsupported ioctl %X", req);
-- 
2.0.0