backends/iommufd: change process ioctl

Define the change process ioctl

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Reviewed-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Link: https://lore.kernel.org/qemu-devel/1751493538-202042-7-git-send-email-steven.sistare@oracle.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>

2 files changed, 25 insertions, 0 deletions

diff --git a/backends/iommufd.c b/backends/iommufd.c
index 3a2ecc7f5b..87f81a05f6 100644
--- a/backends/iommufd.c
+++ b/backends/iommufd.c
@@ -73,6 +73,30 @@ static void iommufd_backend_class_init(ObjectClass *oc, const void *data)
     object_class_property_add_str(oc, "fd", NULL, iommufd_backend_set_fd);
 }
 
+bool iommufd_change_process_capable(IOMMUFDBackend *be)
+{
+    struct iommu_ioas_change_process args = {.size = sizeof(args)};
+
+    /*
+     * Call IOMMU_IOAS_CHANGE_PROCESS to verify it is a recognized ioctl.
+     * This is a no-op if the process has not changed since DMA was mapped.
+     */
+    return !ioctl(be->fd, IOMMU_IOAS_CHANGE_PROCESS, &args);
+}
+
+bool iommufd_change_process(IOMMUFDBackend *be, Error **errp)
+{
+    struct iommu_ioas_change_process args = {.size = sizeof(args)};
+    bool ret = !ioctl(be->fd, IOMMU_IOAS_CHANGE_PROCESS, &args);
+
+    if (!ret) {
+        error_setg_errno(errp, errno, "IOMMU_IOAS_CHANGE_PROCESS fd %d failed",
+                         be->fd);
+    }
+    trace_iommufd_change_process(be->fd, ret);
+    return ret;
+}
+
 bool iommufd_backend_connect(IOMMUFDBackend *be, Error **errp)
 {
     int fd;
diff --git a/backends/trace-events b/backends/trace-events
index e5f3e70cd1..56132d3fd2 100644
--- a/backends/trace-events
+++ b/backends/trace-events
@@ -7,6 +7,7 @@ dbus_vmstate_loading(const char *id) "id: %s"
 dbus_vmstate_saving(const char *id) "id: %s"
 
 # iommufd.c
+iommufd_change_process(int fd, bool ret) "fd=%d (%d)"
 iommufd_backend_connect(int fd, bool owned, uint32_t users) "fd=%d owned=%d users=%d"
 iommufd_backend_disconnect(int fd, uint32_t users) "fd=%d users=%d"
 iommu_backend_set_fd(int fd) "pre-opened /dev/iommu fd=%d"