>-----Original Message-----
>From: Steve Sistare <steven.sist...@oracle.com>
>Subject: [PATCH V5 32/38] vfio/iommufd: preserve descriptors
>
>Save the iommu and vfio device fd in CPR state when it is created.
>After CPR, the fd number is found in CPR state and reused.
>
>Signed-off-by: Steve Sistare <steven.sist...@oracle.com>
>---
> backends/iommufd.c | 25 ++++++++++++++++++++++++-
> hw/vfio/cpr-iommufd.c | 10 ++++++++++
> hw/vfio/device.c | 9 +--------
> 3 files changed, 35 insertions(+), 9 deletions(-)
>
>diff --git a/backends/iommufd.c b/backends/iommufd.c
>index c554ce5..e02f06e 100644
>--- a/backends/iommufd.c
>+++ b/backends/iommufd.c
>@@ -16,12 +16,18 @@
> #include "qemu/module.h"
> #include "qom/object_interfaces.h"
> #include "qemu/error-report.h"
>+#include "migration/cpr.h"
> #include "monitor/monitor.h"
> #include "trace.h"
> #include "hw/vfio/vfio-device.h"
> #include <sys/ioctl.h>
> #include <linux/iommufd.h>
>
>+static const char *iommufd_fd_name(IOMMUFDBackend *be)
>+{
>+ return object_get_canonical_path_component(OBJECT(be));
>+}
>+
> static void iommufd_backend_init(Object *obj)
> {
> IOMMUFDBackend *be = IOMMUFD_BACKEND(obj);
>@@ -64,11 +70,27 @@ static bool
>iommufd_backend_can_be_deleted(UserCreatable *uc)
> return !be->users;
> }
>
>+static void iommufd_backend_complete(UserCreatable *uc, Error **errp)
>+{
>+ IOMMUFDBackend *be = IOMMUFD_BACKEND(uc);
>+ const char *name = iommufd_fd_name(be);
>+
>+ if (!be->owned) {
>+ /* fd came from the command line. Fetch updated value from cpr state.
>*/
>+ if (cpr_is_incoming()) {
>+ be->fd = cpr_find_fd(name, 0);
>+ } else {
>+ cpr_save_fd(name, 0, be->fd);
>+ }
Maybe this can be handled in iommufd_backend_set_fd() instead of introducing
complete callback? Can we call cpr_get_fd_param()?
>+ }
>+}
>+
> static void iommufd_backend_class_init(ObjectClass *oc, const void *data)
> {
> UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
>
> ucc->can_be_deleted = iommufd_backend_can_be_deleted;
>+ ucc->complete = iommufd_backend_complete;
>
> object_class_property_add_str(oc, "fd", NULL, iommufd_backend_set_fd);
> }
>@@ -102,7 +124,7 @@ bool iommufd_backend_connect(IOMMUFDBackend *be,
>Error **errp)
> int fd;
>
> if (be->owned && !be->users) {
>- fd = qemu_open("/dev/iommu", O_RDWR, errp);
>+ fd = cpr_open_fd("/dev/iommu", O_RDWR, iommufd_fd_name(be), 0, errp);
> if (fd < 0) {
> return false;
> }
>@@ -134,6 +156,7 @@ void iommufd_backend_disconnect(IOMMUFDBackend
>*be)
> out:
> if (!be->users) {
> vfio_iommufd_cpr_unregister_iommufd(be);
>+ cpr_delete_fd(iommufd_fd_name(be), 0);
I think we shouldn't call this if not owned.
> }
> trace_iommufd_backend_disconnect(be->fd, be->users);
> }
>diff --git a/hw/vfio/cpr-iommufd.c b/hw/vfio/cpr-iommufd.c
>index 2eca8a6..152a661 100644
>--- a/hw/vfio/cpr-iommufd.c
>+++ b/hw/vfio/cpr-iommufd.c
>@@ -162,17 +162,27 @@ void
>vfio_iommufd_cpr_unregister_container(VFIOIOMMUFDContainer *container)
> void vfio_iommufd_cpr_register_device(VFIODevice *vbasedev)
> {
> if (!cpr_is_incoming()) {
>+ /*
>+ * Beware fd may have already been saved by vfio_device_set_fd,
>+ * so call resave to avoid a duplicate entry.
>+ */
>+ cpr_resave_fd(vbasedev->name, 0, vbasedev->fd);
> vfio_cpr_save_device(vbasedev);
> }
> }
>
> void vfio_iommufd_cpr_unregister_device(VFIODevice *vbasedev)
> {
>+ cpr_delete_fd(vbasedev->name, 0);
> vfio_cpr_delete_device(vbasedev->name);
> }
>
> void vfio_cpr_load_device(VFIODevice *vbasedev)
> {
>+ if (vbasedev->fd < 0) {
>+ vbasedev->fd = cpr_find_fd(vbasedev->name, 0);
Maybe call this after checking cpr_is_incoming()?
>+ }
>+
> if (cpr_is_incoming()) {
> bool ret = vfio_cpr_find_device(vbasedev);
> g_assert(ret);
>diff --git a/hw/vfio/device.c b/hw/vfio/device.c
>index 8c3835b..6bcc65c 100644
>--- a/hw/vfio/device.c
>+++ b/hw/vfio/device.c
>@@ -335,14 +335,7 @@ void vfio_device_free_name(VFIODevice *vbasedev)
>
> void vfio_device_set_fd(VFIODevice *vbasedev, const char *str, Error **errp)
> {
>- ERRP_GUARD();
>- int fd = monitor_fd_param(monitor_cur(), str, errp);
>-
>- if (fd < 0) {
>- error_prepend(errp, "Could not parse remote object fd %s:", str);
>- return;
>- }
>- vbasedev->fd = fd;
>+ vbasedev->fd = cpr_get_fd_param(vbasedev->dev->id, str, 0, errp);
> }
>
> static VFIODeviceIOOps vfio_device_io_ops_ioctl;
>--
>1.8.3.1
