From: Steve Sistare <steven.sistare@oracle.com>

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>
---
 include/system/iommufd.h |  3 +++
 backends/iommufd.c       | 24 ++++++++++++++++++++++++
 backends/trace-events    |  1 +
 3 files changed, 28 insertions(+)

diff --git a/include/system/iommufd.h b/include/system/iommufd.h
index 2d24d93d17e280bce53030a52588bd91425e03ea..db5f2c716c5be6cd1313045ab6dd28eb1f8356f3 100644
--- a/include/system/iommufd.h
+++ b/include/system/iommufd.h
@@ -69,6 +69,9 @@ bool iommufd_backend_invalidate_cache(IOMMUFDBackend *be, uint32_t id,
                                       uint32_t *entry_num, void *data,
                                       Error **errp);
 
+bool iommufd_change_process_capable(IOMMUFDBackend *be);
+bool iommufd_change_process(IOMMUFDBackend *be, Error **errp);
+
 #define TYPE_HOST_IOMMU_DEVICE_IOMMUFD TYPE_HOST_IOMMU_DEVICE "-iommufd"
 OBJECT_DECLARE_TYPE(HostIOMMUDeviceIOMMUFD, HostIOMMUDeviceIOMMUFDClass,
                     HOST_IOMMU_DEVICE_IOMMUFD)
diff --git a/backends/iommufd.c b/backends/iommufd.c
index 3a2ecc7f5ba67699249ae1ad632fc8a45e9b53d3..87f81a05f6465cabc5673745f95947db2bb4a4fb 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 e5f3e70cd1ba7eb532c8f763b12460ef8f552245..56132d3fd22b5a217b07349c74f17e50d553a799 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"
-- 
2.50.0