cpr-transfer breaks vfio network connectivity to and from the guest, and
the host system log shows:
irq bypass consumer (token 00000000a03c32e5) registration fails: -16
which is EBUSY. This occurs because KVM descriptors are still open in
the old QEMU process. Close them.
Cc: Paolo Bonzini <pbonz...@redhat.com>
Signed-off-by: Steve Sistare <steven.sist...@oracle.com>
---
include/hw/vfio/vfio-device.h | 2 ++
include/migration/cpr.h | 2 ++
include/system/kvm.h | 1 +
accel/kvm/kvm-all.c | 32 ++++++++++++++++++++++++++++++++
accel/stubs/kvm-stub.c | 5 +++++
hw/vfio/helpers.c | 10 ++++++++++
hw/vfio/vfio-stubs.c | 13 +++++++++++++
migration/cpr-transfer.c | 18 ++++++++++++++++++
migration/cpr.c | 8 ++++++++
migration/migration.c | 1 +
hw/vfio/meson.build | 2 ++
11 files changed, 94 insertions(+)
create mode 100644 hw/vfio/vfio-stubs.c
diff --git a/include/hw/vfio/vfio-device.h b/include/hw/vfio/vfio-device.h
index 4e4d0b6..6eb6f21 100644
--- a/include/hw/vfio/vfio-device.h
+++ b/include/hw/vfio/vfio-device.h
@@ -231,4 +231,6 @@ void vfio_device_set_fd(VFIODevice *vbasedev, const char
*str, Error **errp);
void vfio_device_init(VFIODevice *vbasedev, int type, VFIODeviceOps *ops,
DeviceState *dev, bool ram_discard);
int vfio_device_get_aw_bits(VFIODevice *vdev);
+
+void vfio_kvm_device_close(void);
#endif /* HW_VFIO_VFIO_COMMON_H */
diff --git a/include/migration/cpr.h b/include/migration/cpr.h
index 07858e9..d09b657 100644
--- a/include/migration/cpr.h
+++ b/include/migration/cpr.h
@@ -32,7 +32,9 @@ void cpr_state_close(void);
struct QIOChannel *cpr_state_ioc(void);
bool cpr_incoming_needed(void *opaque);
+void cpr_kvm_close(void);
+void cpr_transfer_init(void);
QEMUFile *cpr_transfer_output(MigrationChannel *channel, Error **errp);
QEMUFile *cpr_transfer_input(MigrationChannel *channel, Error **errp);
diff --git a/include/system/kvm.h b/include/system/kvm.h
index 7cc60d2..4896a3c 100644
--- a/include/system/kvm.h
+++ b/include/system/kvm.h
@@ -195,6 +195,7 @@ bool kvm_has_sync_mmu(void);
int kvm_has_vcpu_events(void);
int kvm_max_nested_state_length(void);
int kvm_has_gsi_routing(void);
+void kvm_close(void);
/**
* kvm_arm_supports_user_irq
diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index a317783..3d3a557 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -515,16 +515,23 @@ static int do_kvm_destroy_vcpu(CPUState *cpu)
goto err;
}
+ /* If I am the CPU that created coalesced_mmio_ring, then discard it */
+ if (s->coalesced_mmio_ring == (void *)cpu->kvm_run + PAGE_SIZE) {
+ s->coalesced_mmio_ring = NULL;
+ }
+
ret = munmap(cpu->kvm_run, mmap_size);
if (ret < 0) {
goto err;
}
+ cpu->kvm_run = NULL;
if (cpu->kvm_dirty_gfns) {
ret = munmap(cpu->kvm_dirty_gfns, s->kvm_dirty_ring_bytes);
if (ret < 0) {
goto err;
}
+ cpu->kvm_dirty_gfns = NULL;
}
kvm_park_vcpu(cpu);
@@ -608,6 +615,31 @@ err:
return ret;
}
+void kvm_close(void)
+{
+ CPUState *cpu;
+
+ if (!kvm_state || kvm_state->fd == -1) {
+ return;
+ }
+
+ CPU_FOREACH(cpu) {
+ cpu_remove_sync(cpu);
+ close(cpu->kvm_fd);
+ cpu->kvm_fd = -1;
+ close(cpu->kvm_vcpu_stats_fd);
+ cpu->kvm_vcpu_stats_fd = -1;
+ }
+
+ if (kvm_state && kvm_state->fd != -1) {
+ close(kvm_state->vmfd);
+ kvm_state->vmfd = -1;
+ close(kvm_state->fd);
+ kvm_state->fd = -1;
+ }
+ kvm_state = NULL;
+}
+
/*
* dirty pages logging control
*/
diff --git a/accel/stubs/kvm-stub.c b/accel/stubs/kvm-stub.c
index ecfd763..97dacb3 100644
--- a/accel/stubs/kvm-stub.c
+++ b/accel/stubs/kvm-stub.c
@@ -134,3 +134,8 @@ int kvm_create_guest_memfd(uint64_t size, uint64_t flags,
Error **errp)
{
return -ENOSYS;
}
+
+void kvm_close(void)
+{
+ return;
+}
diff --git a/hw/vfio/helpers.c b/hw/vfio/helpers.c
index d0dbab1..af1db2f 100644
--- a/hw/vfio/helpers.c
+++ b/hw/vfio/helpers.c
@@ -117,6 +117,16 @@ bool vfio_get_info_dma_avail(struct vfio_iommu_type1_info
*info,
int vfio_kvm_device_fd = -1;
#endif
+void vfio_kvm_device_close(void)
+{
+#ifdef CONFIG_KVM
+ if (vfio_kvm_device_fd != -1) {
+ close(vfio_kvm_device_fd);
+ vfio_kvm_device_fd = -1;
+ }
+#endif
+}
+
int vfio_kvm_device_add_fd(int fd, Error **errp)
{
#ifdef CONFIG_KVM
diff --git a/hw/vfio/vfio-stubs.c b/hw/vfio/vfio-stubs.c
new file mode 100644
index 0000000..a4c8b56
--- /dev/null
+++ b/hw/vfio/vfio-stubs.c
@@ -0,0 +1,13 @@
+/*
+ * Copyright (c) 2025 Oracle and/or its affiliates.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "hw/vfio/vfio-device.h"
+
+void vfio_kvm_device_close(void)
+{
+ return;
+}
diff --git a/migration/cpr-transfer.c b/migration/cpr-transfer.c
index e1f1403..396558f 100644
--- a/migration/cpr-transfer.c
+++ b/migration/cpr-transfer.c
@@ -17,6 +17,24 @@
#include "migration/vmstate.h"
#include "trace.h"
+static int cpr_transfer_notifier(NotifierWithReturn *notifier,
+ MigrationEvent *e,
+ Error **errp)
+{
+ if (e->type == MIG_EVENT_PRECOPY_DONE) {
+ cpr_kvm_close();
+ }
+ return 0;
+}
+
+void cpr_transfer_init(void)
+{
+ static NotifierWithReturn notifier;
+
+ migration_add_notifier_mode(¬ifier, cpr_transfer_notifier,
+ MIG_MODE_CPR_TRANSFER);
+}
+
QEMUFile *cpr_transfer_output(MigrationChannel *channel, Error **errp)
{
MigrationAddress *addr = channel->addr;
diff --git a/migration/cpr.c b/migration/cpr.c
index a50a57e..49fb0a5 100644
--- a/migration/cpr.c
+++ b/migration/cpr.c
@@ -7,12 +7,14 @@
#include "qemu/osdep.h"
#include "qapi/error.h"
+#include "hw/vfio/vfio-device.h"
#include "migration/cpr.h"
#include "migration/misc.h"
#include "migration/options.h"
#include "migration/qemu-file.h"
#include "migration/savevm.h"
#include "migration/vmstate.h"
+#include "system/kvm.h"
#include "system/runstate.h"
#include "trace.h"
@@ -264,3 +266,9 @@ bool cpr_incoming_needed(void *opaque)
MigMode mode = migrate_mode();
return mode == MIG_MODE_CPR_TRANSFER;
}
+
+void cpr_kvm_close(void)
+{
+ kvm_close();
+ vfio_kvm_device_close();
+}
diff --git a/migration/migration.c b/migration/migration.c
index 4098870..8f23cff 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -337,6 +337,7 @@ void migration_object_init(void)
ram_mig_init();
dirty_bitmap_mig_init();
+ cpr_transfer_init();
/* Initialize cpu throttle timers */
cpu_throttle_init();
diff --git a/hw/vfio/meson.build b/hw/vfio/meson.build
index 73d29f9..98134a7 100644
--- a/hw/vfio/meson.build
+++ b/hw/vfio/meson.build
@@ -17,6 +17,8 @@ vfio_ss.add(when: 'CONFIG_VFIO_IGD', if_true: files('igd.c'))
specific_ss.add_all(when: 'CONFIG_VFIO', if_true: vfio_ss)
+system_ss.add(when: 'CONFIG_VFIO', if_false: files('vfio-stubs.c'))
+
system_ss.add(when: 'CONFIG_VFIO_XGMAC', if_true: files('calxeda-xgmac.c'))
system_ss.add(when: 'CONFIG_VFIO_AMD_XGBE', if_true: files('amd-xgbe.c'))
system_ss.add(when: 'CONFIG_VFIO', if_true: files(
