cpr-transfer will use the device name as a key to find the value
of the device descriptor in new QEMU. However, if the descriptor
number is specified by a command-line fd parameter, then
vfio_device_get_name creates a name that includes the fd number.
This causes a chicken-and-egg problem: new QEMU must know the fd
number to construct a name to find the fd number.
To fix, create an invariant name based on the id command-line
parameter. If id is not defined, add a CPR blocker.
Signed-off-by: Steve Sistare <steven.sist...@oracle.com>
---
hw/vfio/cpr.c | 21 +++++++++++++++++++++
hw/vfio/helpers.c | 10 ++++------
hw/vfio/iommufd.c | 2 ++
include/hw/vfio/vfio-cpr.h | 4 ++++
4 files changed, 31 insertions(+), 6 deletions(-)
diff --git a/hw/vfio/cpr.c b/hw/vfio/cpr.c
index a2400ca..e3ea2bf 100644
--- a/hw/vfio/cpr.c
+++ b/hw/vfio/cpr.c
@@ -11,6 +11,7 @@
#include "hw/vfio/pci.h"
#include "hw/pci/msix.h"
#include "hw/pci/msi.h"
+#include "migration/blocker.h"
#include "migration/cpr.h"
#include "qapi/error.h"
#include "system/runstate.h"
@@ -184,3 +185,23 @@ const VMStateDescription vfio_cpr_pci_vmstate = {
VMSTATE_END_OF_LIST()
}
};
+
+bool vfio_cpr_set_device_name(VFIODevice *vbasedev, Error **errp)
+{
+ if (vbasedev->dev->id) {
+ vbasedev->name = g_strdup(vbasedev->dev->id);
+ return true;
+ } else {
+ /*
+ * Assign a name so any function printing it will not break, but the
+ * fd number changes across processes, so this cannot be used as an
+ * invariant name for CPR.
+ */
+ vbasedev->name = g_strdup_printf("VFIO_FD%d", vbasedev->fd);
+ error_setg(&vbasedev->cpr.id_blocker,
+ "vfio device with fd=%d needs an id property",
+ vbasedev->fd);
+ return migrate_add_blocker_modes(&vbasedev->cpr.id_blocker, errp,
+ MIG_MODE_CPR_TRANSFER, -1) == 0;
+ }
+}
diff --git a/hw/vfio/helpers.c b/hw/vfio/helpers.c
index 4b255d4..4ff794c 100644
--- a/hw/vfio/helpers.c
+++ b/hw/vfio/helpers.c
@@ -29,6 +29,7 @@
#include "qapi/error.h"
#include "qemu/error-report.h"
#include "qemu/units.h"
+#include "migration/cpr.h"
#include "monitor/monitor.h"
/*
@@ -637,6 +638,7 @@ bool vfio_device_get_name(VFIODevice *vbasedev, Error
**errp)
{
ERRP_GUARD();
struct stat st;
+ bool ret = true;
if (vbasedev->fd < 0) {
if (stat(vbasedev->sysfsdev, &st) < 0) {
@@ -653,16 +655,12 @@ bool vfio_device_get_name(VFIODevice *vbasedev, Error
**errp)
error_setg(errp, "Use FD passing only with iommufd backend");
return false;
}
- /*
- * Give a name with fd so any function printing out vbasedev->name
- * will not break.
- */
if (!vbasedev->name) {
- vbasedev->name = g_strdup_printf("VFIO_FD%d", vbasedev->fd);
+ ret = vfio_cpr_set_device_name(vbasedev, errp);
}
}
- return true;
+ return ret;
}
void vfio_device_set_fd(VFIODevice *vbasedev, const char *str, Error **errp)
diff --git a/hw/vfio/iommufd.c b/hw/vfio/iommufd.c
index 7c0cdd7..2de2811 100644
--- a/hw/vfio/iommufd.c
+++ b/hw/vfio/iommufd.c
@@ -24,6 +24,7 @@
#include "system/reset.h"
#include "qemu/cutils.h"
#include "qemu/chardev_open.h"
+#include "migration/blocker.h"
#include "pci.h"
#include "exec/ram_addr.h"
@@ -661,6 +662,7 @@ static void iommufd_cdev_detach(VFIODevice *vbasedev)
iommufd_cdev_container_destroy(container);
vfio_put_address_space(space);
+ migrate_del_blocker(&vbasedev->cpr.id_blocker);
iommufd_cdev_unbind_and_disconnect(vbasedev);
close(vbasedev->fd);
}
diff --git a/include/hw/vfio/vfio-cpr.h b/include/hw/vfio/vfio-cpr.h
index a9f2fbe..8a30d30 100644
--- a/include/hw/vfio/vfio-cpr.h
+++ b/include/hw/vfio/vfio-cpr.h
@@ -22,12 +22,14 @@ typedef struct VFIOContainerCPR {
typedef struct VFIODeviceCPR {
bool reused;
Error *mdev_blocker;
+ Error *id_blocker;
} VFIODeviceCPR;
struct VFIOContainer;
struct VFIOGroup;
struct VFIOContainerBase;
struct VFIOPCIDevice;
+struct VFIODevice;
int vfio_cpr_reboot_notifier(NotifierWithReturn *notifier, MigrationEvent *e,
Error **errp);
@@ -53,4 +55,6 @@ void vfio_cpr_delete_vector_fd(struct VFIOPCIDevice *vdev,
const char *name,
int nr);
extern const VMStateDescription vfio_cpr_pci_vmstate;
+
+bool vfio_cpr_set_device_name(struct VFIODevice *vbasedev, Error **errp);
#endif
--
1.8.3.1
