* [PATCH v7 01/15] s390/vfio-ap: Provide function to get the number of queues assigned to mdev
2026-08-07 22:18 [PATCH v7 00/15] s390/vfio-ap: Add live guest migration support Anthony Krowiak
@ 2026-08-07 22:18 ` Anthony Krowiak
2026-08-07 22:18 ` [PATCH v7 02/15] s390/vfio-ap: Data structures for facilitating vfio device migration Anthony Krowiak
` (13 subsequent siblings)
14 siblings, 0 replies; 16+ messages in thread
From: Anthony Krowiak @ 2026-08-07 22:18 UTC (permalink / raw)
To: linux-s390, linux-kernel, kvm
Cc: jjherne, borntraeger, mjrosato, pasic, alex, kwankhede, fiuczy,
pbonzini, frankja, imbrenda, agordeev, hca, gor
Provides a function that returns the number of queues that are or will be
passed through to a guest when the mdev is attached to a guest.
Signed-off-by: Anthony Krowiak <akrowiak@linux.ibm.com>
---
drivers/s390/crypto/vfio_ap_ops.c | 8 ++++++++
drivers/s390/crypto/vfio_ap_private.h | 2 ++
2 files changed, 10 insertions(+)
diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index 44b3a1dcc1b3..36786d70a88f 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -2098,6 +2098,14 @@ static void vfio_ap_mdev_request(struct vfio_device *vdev, unsigned int count)
release_update_locks_for_mdev(matrix_mdev);
}
+int vfio_ap_mdev_get_num_queues(struct ap_matrix *ap_matrix)
+{
+ lockdep_assert_held(&matrix_dev->mdevs_lock);
+
+ return bitmap_weight(ap_matrix->apm, AP_DEVICES) *
+ bitmap_weight(ap_matrix->aqm, AP_DOMAINS);
+}
+
static int vfio_ap_mdev_get_device_info(unsigned long arg)
{
unsigned long minsz;
diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h
index 9bff666b0b35..9677e49554d7 100644
--- a/drivers/s390/crypto/vfio_ap_private.h
+++ b/drivers/s390/crypto/vfio_ap_private.h
@@ -152,6 +152,8 @@ struct vfio_ap_queue {
struct work_struct reset_work;
};
+int vfio_ap_mdev_get_num_queues(struct ap_matrix *ap_matrix);
+
int vfio_ap_mdev_register(void);
void vfio_ap_mdev_unregister(void);
--
2.53.0
^ permalink raw reply related [flat|nested] 16+ messages in thread* [PATCH v7 02/15] s390/vfio-ap: Data structures for facilitating vfio device migration
2026-08-07 22:18 [PATCH v7 00/15] s390/vfio-ap: Add live guest migration support Anthony Krowiak
2026-08-07 22:18 ` [PATCH v7 01/15] s390/vfio-ap: Provide function to get the number of queues assigned to mdev Anthony Krowiak
@ 2026-08-07 22:18 ` Anthony Krowiak
2026-08-07 22:18 ` [PATCH v7 03/15] s390/vfio-ap: Functions to initialize/release vfio device migration data Anthony Krowiak
` (12 subsequent siblings)
14 siblings, 0 replies; 16+ messages in thread
From: Anthony Krowiak @ 2026-08-07 22:18 UTC (permalink / raw)
To: linux-s390, linux-kernel, kvm
Cc: jjherne, borntraeger, mjrosato, pasic, alex, kwankhede, fiuczy,
pbonzini, frankja, imbrenda, agordeev, hca, gor
Creates the data structures used to facilitate state transitions during
vfio device migration.
Signed-off-by: Anthony Krowiak <akrowiak@linux.ibm.com>
---
drivers/s390/crypto/Makefile | 2 +-
drivers/s390/crypto/vfio_ap_migration.c | 113 ++++++++++++++++++++++++
drivers/s390/crypto/vfio_ap_private.h | 5 ++
3 files changed, 119 insertions(+), 1 deletion(-)
create mode 100644 drivers/s390/crypto/vfio_ap_migration.c
diff --git a/drivers/s390/crypto/Makefile b/drivers/s390/crypto/Makefile
index e83c6603c858..20f29184825a 100644
--- a/drivers/s390/crypto/Makefile
+++ b/drivers/s390/crypto/Makefile
@@ -34,5 +34,5 @@ pkey-uv-objs := pkey_uv.o
obj-$(CONFIG_PKEY_UV) += pkey-uv.o
# adjunct processor matrix
-vfio_ap-objs := vfio_ap_drv.o vfio_ap_ops.o
+vfio_ap-objs := vfio_ap_drv.o vfio_ap_ops.o vfio_ap_migration.o
obj-$(CONFIG_VFIO_AP) += vfio_ap.o
diff --git a/drivers/s390/crypto/vfio_ap_migration.c b/drivers/s390/crypto/vfio_ap_migration.c
new file mode 100644
index 000000000000..374d3a67cb21
--- /dev/null
+++ b/drivers/s390/crypto/vfio_ap_migration.c
@@ -0,0 +1,113 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Drives vfio_ap mdev migration.
+ *
+ * Copyright IBM Corp. 2025
+ */
+#include "vfio_ap_private.h"
+
+/* Magic number and version for the vfio_ap_config migration blob */
+#define VFIO_AP_MIG_MAGIC 0x76666170U /* "vfap" */
+#define VFIO_AP_MIG_VERSION 1U
+
+/**
+ * struct vfio_ap_migration_file
+ *
+ * This object is used for chunk processing of multiple reads and writes of
+ * AP configuration information.
+ *
+ * @filp: file stream used to read or write AP configuration data
+ * @ap_config: object used to store AP configuration data between read or write
+ * calls
+ * @config_sz: the size (in bytes) of @ap_config
+ */
+struct vfio_ap_migration_file {
+ struct file *filp;
+ struct vfio_ap_config *ap_config;
+ unsigned long config_sz;
+};
+
+/**
+ * struct vfio_ap_migration_data:
+ *
+ * Manages the migration state for the VFIO device that maintains the AP
+ * configuration of the guest being migrated.
+ *
+ * @mig_state: the current migration state
+ * @resuming_mig_file: the object used to restore the state of the vfio-ap
+ * device on the destination host.
+ * @stop_copy_mig_file: the object used to store the AP configuration of the
+ * source guest for transfer to the destination host.
+ */
+struct vfio_ap_migration_data {
+ enum vfio_device_mig_state mig_state;
+ struct vfio_ap_migration_file resuming_mig_file;
+ struct vfio_ap_migration_file stop_copy_mig_file;
+};
+
+/**
+ * struct vfio_ap_queue_info - the information for an AP queue
+ *
+ * @data: contains the queue information returned in GR2 from the PQAP(TAPQ)
+ * command
+ * @apqn: the APQN of the queue
+ * @reserved: padding to ensure consistent structure size across platforms
+ */
+struct vfio_ap_queue_info {
+ u64 data;
+ u16 apqn;
+ u8 reserved[6];
+};
+
+/**
+ * struct vfio_ap_config:
+ *
+ * Stores the state of a guest's AP configuration.
+ *
+ * VFIO device migration state transition from STOP to STOP_COPY:
+ * -------------------------------------------------------------
+ * When the migration state transitions from STOP to STOP_COPY, the vfio_ap device
+ * driver will open a file stream in read-only mode and return the fd to userspace.
+ * This fd is used during the STOP_COPY phase to read the current state of the
+ * vfio-ap device on the source host. In response, the driver will store the
+ * source guest's AP configuration data in a vfio_ap_config object and copy it to
+ * userspace.
+ *
+ * VFIO device migration state transition from STOP to RESUMING:
+ * ------------------------------------------------------------
+ * When the VFIO migration state transitions from STOP to RESUMING,
+ * the vfio_ap device driver will open a file stream in write-only mode and
+ * return the fd to userspace. This fd is used during the RESUMING phase to
+ * write the source guest's vfio_ap_config data that was read in during the
+ * STOP_COPY phase to the vfio_ap device driver on the destination host. In
+ * response, the device driver will copy the data sent from userspace to a
+ * vfio_ap_config instance which is then used to update the destination guest's
+ * AP configuration.
+ *
+ * Since the source and destination hosts may be running different versions of
+ * the linux kernel, the vfio_ap_config object provides two fields (@magic and
+ * @version) which must be set by the source device driver and verified by the
+ * destination device driver to ensure the migration ABI of the source and
+ * destination hosts are compatible.
+ *
+ * Note: Since a guest's AP configuration could be comprise of a large number of
+ * AP queue devices, a vfio_ap_config object should be allocated using
+ * kvzalloc.
+ *
+ * @magic: identifies this as a valid vfio_ap_config migration blob;
+ * must equal VFIO_AP_MIG_MAGIC
+ * @version: layout version; must equal VFIO_AP_MIG_VERSION
+ * @num_queues: the number of queues passed through to the guest
+ * @reserved: padding to ensure proper alignment of @adm
+ * @adm: bitmap specifying the control domains in the AP configuration
+ * @qinfo: an array of vfio_ap_queue_info objects, each specifying the
+ * queue information for a queue passed through to the guest
+ */
+struct vfio_ap_config {
+ u32 magic;
+ u32 version;
+ u32 num_queues;
+ u8 reserved[4];
+ u64 adm[DIV_ROUND_UP(AP_DOMAINS, 64)];
+ struct vfio_ap_queue_info qinfo[] __counted_by(num_queues);
+};
diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h
index 9677e49554d7..2b542648964b 100644
--- a/drivers/s390/crypto/vfio_ap_private.h
+++ b/drivers/s390/crypto/vfio_ap_private.h
@@ -91,6 +91,9 @@ struct ap_queue_table {
DECLARE_HASHTABLE(queues, 8);
};
+/* Forward declaration for migration data structure */
+struct vfio_ap_migration_data;
+
/**
* struct ap_matrix_mdev - Contains the data associated with a matrix mediated
* device.
@@ -110,6 +113,7 @@ struct ap_queue_table {
* @aqm_add: bitmap of APQIs added to the host's AP configuration
* @adm_add: bitmap of control domain numbers added to the host's AP
* configuration
+ * @mig_data: vfio device migration data
*/
struct ap_matrix_mdev {
struct vfio_device vdev;
@@ -125,6 +129,7 @@ struct ap_matrix_mdev {
DECLARE_BITMAP(apm_add, AP_DEVICES);
DECLARE_BITMAP(aqm_add, AP_DOMAINS);
DECLARE_BITMAP(adm_add, AP_DOMAINS);
+ struct vfio_ap_migration_data *mig_data;
};
/**
--
2.53.0
^ permalink raw reply related [flat|nested] 16+ messages in thread* [PATCH v7 03/15] s390/vfio-ap: Functions to initialize/release vfio device migration data
2026-08-07 22:18 [PATCH v7 00/15] s390/vfio-ap: Add live guest migration support Anthony Krowiak
2026-08-07 22:18 ` [PATCH v7 01/15] s390/vfio-ap: Provide function to get the number of queues assigned to mdev Anthony Krowiak
2026-08-07 22:18 ` [PATCH v7 02/15] s390/vfio-ap: Data structures for facilitating vfio device migration Anthony Krowiak
@ 2026-08-07 22:18 ` Anthony Krowiak
2026-08-07 22:18 ` [PATCH v7 04/15] s390/vfio-ap: Reset migration state in VFIO_DEVICE_RESET ioctl handler Anthony Krowiak
` (11 subsequent siblings)
14 siblings, 0 replies; 16+ messages in thread
From: Anthony Krowiak @ 2026-08-07 22:18 UTC (permalink / raw)
To: linux-s390, linux-kernel, kvm
Cc: jjherne, borntraeger, mjrosato, pasic, alex, kwankhede, fiuczy,
pbonzini, frankja, imbrenda, agordeev, hca, gor
Provides the functions that initialize and release the data structures
used during live guest migration:
* vfio_ap_init_migration_capabilities
Sets the migration flags and vfio_migration_ops structure into the
vfio_device object when the mdev is probed.
* vfio_ap_init_migration_data
Allocates and initializes the object used to maintain the state of the
VFIO migration. It is called when the VFIO device is opened.
* vfio_ap_release_migration_data
Frees the memory of the object used to maintain the VFIO migration state.
It is called when the VFIO device release callback is invoked and when
the VFIO device is closed.
* vfio_ap_release_mig_files
This function is called from the vfio_ap_release_migration_data
function (above) and releases the vfio_ap_migration_file objects
contained within the vfio_ap_migation_data object used to maintain the
state of the VFIO migration process.
* vfio_ap_release_stop_copy_file
This function is called from the vfio_ap_release_mig_files
function (above) to release the vfio_ap_migration_file used
during the STOP_COPY phase of migration. For now, this is a
stub function that will be fully implemented in a subsequent
patch after the vfio_ap_config object referenced within
is allocated, as it will need to be freed according to how it
is allocated
* vfio_ap_release_resuming_file
This function is called from the vfio_ap_release_mig_files
function (above) to release the vfio_ap_migration_file used
during the RESUMING phase of migration. For now, this is a
stub function that will be fully implemented in a subsequent
patch after the vfio_ap_config object referenced within
is allocated, as it will need to be freed according to how it
is allocated
* vfio_ap_set_state, vfio_ap_get_state and vfio_ap_get_data_size
These three functions are callback functions assigned to the
vfio_ap_migration_ops (.migration_set_state, .migration_get_state and
.migration_get_data_size function pointers). These are implemented
as stub functions here and each will be fully implemented in a subsequent
patch.
Signed-off-by: Anthony Krowiak <akrowiak@linux.ibm.com>
---
drivers/s390/crypto/vfio_ap_migration.c | 127 ++++++++++++++++++++++++
drivers/s390/crypto/vfio_ap_ops.c | 64 ++++++++++--
drivers/s390/crypto/vfio_ap_private.h | 4 +
3 files changed, 187 insertions(+), 8 deletions(-)
diff --git a/drivers/s390/crypto/vfio_ap_migration.c b/drivers/s390/crypto/vfio_ap_migration.c
index 374d3a67cb21..cf303d228a0a 100644
--- a/drivers/s390/crypto/vfio_ap_migration.c
+++ b/drivers/s390/crypto/vfio_ap_migration.c
@@ -4,6 +4,7 @@
*
* Copyright IBM Corp. 2025
*/
+#include <linux/file.h>
#include "vfio_ap_private.h"
/* Magic number and version for the vfio_ap_config migration blob */
@@ -111,3 +112,129 @@ struct vfio_ap_config {
u64 adm[DIV_ROUND_UP(AP_DOMAINS, 64)];
struct vfio_ap_queue_info qinfo[] __counted_by(num_queues);
};
+
+static void
+vfio_ap_release_stop_copy_file(struct vfio_ap_migration_data *mig_data)
+{
+ /* Stub to be implemented when the mig_data->stop_copy_mig_file.ap_config
+ * object is allocated.
+ */
+}
+
+static void vfio_ap_release_resuming_file(struct vfio_ap_migration_data *mig_data)
+{
+ /* Stub to be implemented when the mig_data->resuming_mig_file.ap_config
+ * object is allocated.
+ */
+}
+
+static struct file *vfio_ap_set_state(struct vfio_device *vdev,
+ enum vfio_device_mig_state new_state)
+{
+ return NULL;
+}
+
+static int vfio_ap_get_state(struct vfio_device *vdev,
+ enum vfio_device_mig_state *current_state)
+{
+ return -EOPNOTSUPP;
+}
+
+static int vfio_ap_get_data_size(struct vfio_device *vdev,
+ unsigned long *stop_copy_length)
+{
+ return -EOPNOTSUPP;
+}
+
+static const struct vfio_migration_ops vfio_ap_migration_ops = {
+ .migration_set_state = vfio_ap_set_state,
+ .migration_get_state = vfio_ap_get_state,
+ .migration_get_data_size = vfio_ap_get_data_size,
+};
+
+/**
+ * vfio_ap_init_migrations_capabilities - initialize migration capabilities
+ *
+ * @matrix_mdev: pointer to object containing the mdev state
+ */
+void vfio_ap_init_migration_capabilities(struct ap_matrix_mdev *matrix_mdev)
+{
+ if (ap_is_se_guest())
+ return;
+
+ matrix_mdev->vdev.migration_flags = VFIO_MIGRATION_STOP_COPY;
+ matrix_mdev->vdev.mig_ops = &vfio_ap_migration_ops;
+}
+
+/**
+ * vfio_ap_init_migration_data - initialize migration data and functions
+ *
+ * @matrix_mdev: pointer to object containing the mdev state
+ *
+ * Return: zero if initialization is successful; otherwise, returns a error.
+ */
+int vfio_ap_init_migration_data(struct ap_matrix_mdev *matrix_mdev)
+{
+ struct vfio_ap_migration_data *mig_data;
+
+ lockdep_assert_held(&matrix_dev->mdevs_lock);
+
+ mig_data = kzalloc_obj(struct vfio_ap_migration_data, GFP_KERNEL);
+ if (!mig_data)
+ return -ENOMEM;
+
+ mig_data->mig_state = VFIO_DEVICE_STATE_RUNNING;
+ matrix_mdev->mig_data = mig_data;
+
+ return 0;
+}
+
+/**
+ * vfio_ap_release_mig_files:
+ *
+ * Free the ap_config buffers for any open migration FDs. Although a
+ * migration FD may still be held open by userspace, it is safe to free
+ * mig_data here because:
+ *
+ * 1. matrix_mdev remains valid for the lifetime of any open migration
+ * FD via the vfio_device registration reference taken in
+ * vfio_ap_open_file_stream() and dropped in
+ * vfio_ap_release_mig_file().
+ *
+ * 2. mig_data is only accessed by the migration file ops
+ * (vfio_ap_stop_copy_read, vfio_ap_resuming_write) under
+ * mdevs_lock. Once mig_data is set to NULL by the caller, those
+ * paths will see NULL and return -ENODEV before dereferencing it.
+ *
+ * @matrix_mdev: The object used to maintain the state for a mediated device
+ */
+static void vfio_ap_release_mig_files(struct ap_matrix_mdev *matrix_mdev)
+{
+ struct vfio_ap_migration_data *mig_data;
+
+ lockdep_assert_held(&matrix_dev->mdevs_lock);
+
+ mig_data = matrix_mdev->mig_data;
+ if (!mig_data)
+ return;
+
+ vfio_ap_release_stop_copy_file(mig_data);
+ vfio_ap_release_resuming_file(mig_data);
+}
+
+/**
+ * vfio_ap_release_migration_data: reclaim private migration data
+ *
+ * @vdev: pointer to the mdev
+ */
+void vfio_ap_release_migration_data(struct ap_matrix_mdev *matrix_mdev)
+{
+ lockdep_assert_held(&matrix_dev->mdevs_lock);
+
+ if (!matrix_mdev->mig_data)
+ return;
+
+ vfio_ap_release_mig_files(matrix_mdev);
+ kfree(matrix_mdev->mig_data);
+ matrix_mdev->mig_data = NULL;
+}
diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index 36786d70a88f..90b0fce0123b 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -775,18 +775,30 @@ static bool vfio_ap_mdev_filter_matrix(struct ap_matrix_mdev *matrix_mdev,
static int vfio_ap_mdev_init_dev(struct vfio_device *vdev)
{
- struct ap_matrix_mdev *matrix_mdev =
- container_of(vdev, struct ap_matrix_mdev, vdev);
+ struct ap_matrix_mdev *matrix_mdev;
+ mutex_lock(&matrix_dev->mdevs_lock);
+ matrix_mdev = container_of(vdev, struct ap_matrix_mdev, vdev);
matrix_mdev->mdev = to_mdev_device(vdev->dev);
vfio_ap_matrix_init(&matrix_dev->info, &matrix_mdev->matrix);
matrix_mdev->pqap_hook = handle_pqap;
vfio_ap_matrix_init(&matrix_dev->info, &matrix_mdev->shadow_apcb);
hash_init(matrix_mdev->qtable.queues);
+ mutex_unlock(&matrix_dev->mdevs_lock);
return 0;
}
+static void vfio_ap_mdev_release_dev(struct vfio_device *vdev)
+{
+ struct ap_matrix_mdev *matrix_mdev;
+
+ mutex_lock(&matrix_dev->mdevs_lock);
+ matrix_mdev = container_of(vdev, struct ap_matrix_mdev, vdev);
+ vfio_ap_release_migration_data(matrix_mdev);
+ mutex_unlock(&matrix_dev->mdevs_lock);
+}
+
static int vfio_ap_mdev_probe(struct mdev_device *mdev)
{
struct ap_matrix_mdev *matrix_mdev;
@@ -797,13 +809,28 @@ static int vfio_ap_mdev_probe(struct mdev_device *mdev)
if (IS_ERR(matrix_mdev))
return PTR_ERR(matrix_mdev);
+ /*
+ * Migration capabilities must be initialized before calling
+ * vfio_register_emulated_iommu_dev; otherwise, the VFIO core
+ * will see mig_ops as NULL during the registration. This could
+ * prevent the VFIO core from properly setting up migration
+ * infrastructure like debugfs entries.
+ *
+ * This must be done before acquiring mdevs_lock to avoid an ABBA
+ * deadlock: vfio_register_emulated_iommu_dev() acquires dev_set->lock
+ * internally, while vfio_ap_mdev_open_device() is called by the VFIO
+ * core with dev_set->lock already held and then acquires mdevs_lock.
+ */
+ vfio_ap_init_migration_capabilities(matrix_mdev);
+
ret = vfio_register_emulated_iommu_dev(&matrix_mdev->vdev);
if (ret)
goto err_put_vdev;
+
+ mutex_lock(&matrix_dev->mdevs_lock);
matrix_mdev->req_trigger = NULL;
matrix_mdev->cfg_chg_trigger = NULL;
dev_set_drvdata(&mdev->dev, matrix_mdev);
- mutex_lock(&matrix_dev->mdevs_lock);
list_add(&matrix_mdev->node, &matrix_dev->mdev_list);
mutex_unlock(&matrix_dev->mdevs_lock);
return 0;
@@ -2052,19 +2079,39 @@ static int vfio_ap_mdev_reset_qlist(struct list_head *qlist)
static int vfio_ap_mdev_open_device(struct vfio_device *vdev)
{
- struct ap_matrix_mdev *matrix_mdev =
- container_of(vdev, struct ap_matrix_mdev, vdev);
+ struct ap_matrix_mdev *matrix_mdev;
+ int ret;
if (!vdev->kvm)
return -EINVAL;
- return vfio_ap_mdev_set_kvm(matrix_mdev, vdev->kvm);
+ mutex_lock(&matrix_dev->mdevs_lock);
+ matrix_mdev = container_of(vdev, struct ap_matrix_mdev, vdev);
+ ret = vfio_ap_init_migration_data(matrix_mdev);
+ mutex_unlock(&matrix_dev->mdevs_lock);
+
+ if (ret)
+ return ret;
+
+ ret = vfio_ap_mdev_set_kvm(matrix_mdev, vdev->kvm);
+ if (ret) {
+ /* Clean up migration data on failure */
+ mutex_lock(&matrix_dev->mdevs_lock);
+ vfio_ap_release_migration_data(matrix_mdev);
+ mutex_unlock(&matrix_dev->mdevs_lock);
+ }
+
+ return ret;
}
static void vfio_ap_mdev_close_device(struct vfio_device *vdev)
{
- struct ap_matrix_mdev *matrix_mdev =
- container_of(vdev, struct ap_matrix_mdev, vdev);
+ struct ap_matrix_mdev *matrix_mdev;
+
+ mutex_lock(&matrix_dev->mdevs_lock);
+ matrix_mdev = container_of(vdev, struct ap_matrix_mdev, vdev);
+ vfio_ap_release_migration_data(matrix_mdev);
+ mutex_unlock(&matrix_dev->mdevs_lock);
vfio_ap_mdev_unset_kvm(matrix_mdev);
}
@@ -2368,6 +2415,7 @@ static const struct attribute_group vfio_queue_attr_group = {
static const struct vfio_device_ops vfio_ap_matrix_dev_ops = {
.init = vfio_ap_mdev_init_dev,
+ .release = vfio_ap_mdev_release_dev,
.open_device = vfio_ap_mdev_open_device,
.close_device = vfio_ap_mdev_close_device,
.ioctl = vfio_ap_mdev_ioctl,
diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h
index 2b542648964b..a2a713f93674 100644
--- a/drivers/s390/crypto/vfio_ap_private.h
+++ b/drivers/s390/crypto/vfio_ap_private.h
@@ -172,4 +172,8 @@ void vfio_ap_on_cfg_changed(struct ap_config_info *new_config_info,
void vfio_ap_on_scan_complete(struct ap_config_info *new_config_info,
struct ap_config_info *old_config_info);
+void vfio_ap_init_migration_capabilities(struct ap_matrix_mdev *matrix_mdev);
+int vfio_ap_init_migration_data(struct ap_matrix_mdev *matrix_mdev);
+void vfio_ap_release_migration_data(struct ap_matrix_mdev *matrix_mdev);
+
#endif /* _VFIO_AP_PRIVATE_H_ */
--
2.53.0
^ permalink raw reply related [flat|nested] 16+ messages in thread* [PATCH v7 04/15] s390/vfio-ap: Reset migration state in VFIO_DEVICE_RESET ioctl handler
2026-08-07 22:18 [PATCH v7 00/15] s390/vfio-ap: Add live guest migration support Anthony Krowiak
` (2 preceding siblings ...)
2026-08-07 22:18 ` [PATCH v7 03/15] s390/vfio-ap: Functions to initialize/release vfio device migration data Anthony Krowiak
@ 2026-08-07 22:18 ` Anthony Krowiak
2026-08-07 22:18 ` [PATCH v7 05/15] s390/vfio-ap: Callback to get/set vfio device mig state during guest migration Anthony Krowiak
` (10 subsequent siblings)
14 siblings, 0 replies; 16+ messages in thread
From: Anthony Krowiak @ 2026-08-07 22:18 UTC (permalink / raw)
To: linux-s390, linux-kernel, kvm
Cc: jjherne, borntraeger, mjrosato, pasic, alex, kwankhede, fiuczy,
pbonzini, frankja, imbrenda, agordeev, hca, gor
According to the VFIO migration specifications, userspace must issue a
VFIO_DEVICE_RESET ioctl if a vfio device enters an error state or fails a
state transition to recover the device and return its migration state to
RUNNING. This patch adds a function that is called when a VFIO_DEVICE_RESET
is issued that releases the migration files and frees the storage allocated
for maintaining the migration state.
Signed-off-by: Anthony Krowiak <akrowiak@linux.ibm.com>
---
drivers/s390/crypto/vfio_ap_migration.c | 20 ++++++++++++++++++++
drivers/s390/crypto/vfio_ap_ops.c | 4 ++++
drivers/s390/crypto/vfio_ap_private.h | 1 +
3 files changed, 25 insertions(+)
diff --git a/drivers/s390/crypto/vfio_ap_migration.c b/drivers/s390/crypto/vfio_ap_migration.c
index cf303d228a0a..1613813124b6 100644
--- a/drivers/s390/crypto/vfio_ap_migration.c
+++ b/drivers/s390/crypto/vfio_ap_migration.c
@@ -238,3 +238,23 @@ void vfio_ap_release_migration_data(struct ap_matrix_mdev *matrix_mdev)
kfree(matrix_mdev->mig_data);
matrix_mdev->mig_data = NULL;
}
+
+/**
+ * vfio_ap_reset_migration_state - Reset the vfio-ap migration state
+ *
+ * @matrix_mdev: pointer to the object maintaining the vfio-ap device state
+ *
+ * Called during VFIO_DEVICE_RESET to clean up any active migration
+ * state and reset the device to RUNNING state as required by the VFIO
+ * migration specification.
+ */
+void vfio_ap_reset_migration_state(struct ap_matrix_mdev *matrix_mdev)
+{
+ lockdep_assert_held(&matrix_dev->mdevs_lock);
+
+ if (!matrix_mdev->mig_data)
+ return;
+
+ vfio_ap_release_mig_files(matrix_mdev);
+ matrix_mdev->mig_data->mig_state = VFIO_DEVICE_STATE_RUNNING;
+}
diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index 90b0fce0123b..d05372b50d2f 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -2330,6 +2330,10 @@ static ssize_t vfio_ap_mdev_ioctl(struct vfio_device *vdev,
break;
case VFIO_DEVICE_RESET:
ret = vfio_ap_mdev_reset_queues(matrix_mdev);
+ if (ret == 0) {
+ /* Reset migration state per VFIO migration spec */
+ vfio_ap_reset_migration_state(matrix_mdev);
+ }
break;
case VFIO_DEVICE_GET_IRQ_INFO:
ret = vfio_ap_get_irq_info(arg);
diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h
index a2a713f93674..1fbdfcce5a11 100644
--- a/drivers/s390/crypto/vfio_ap_private.h
+++ b/drivers/s390/crypto/vfio_ap_private.h
@@ -175,5 +175,6 @@ void vfio_ap_on_scan_complete(struct ap_config_info *new_config_info,
void vfio_ap_init_migration_capabilities(struct ap_matrix_mdev *matrix_mdev);
int vfio_ap_init_migration_data(struct ap_matrix_mdev *matrix_mdev);
void vfio_ap_release_migration_data(struct ap_matrix_mdev *matrix_mdev);
+void vfio_ap_reset_migration_state(struct ap_matrix_mdev *matrix_mdev);
#endif /* _VFIO_AP_PRIVATE_H_ */
--
2.53.0
^ permalink raw reply related [flat|nested] 16+ messages in thread* [PATCH v7 05/15] s390/vfio-ap: Callback to get/set vfio device mig state during guest migration
2026-08-07 22:18 [PATCH v7 00/15] s390/vfio-ap: Add live guest migration support Anthony Krowiak
` (3 preceding siblings ...)
2026-08-07 22:18 ` [PATCH v7 04/15] s390/vfio-ap: Reset migration state in VFIO_DEVICE_RESET ioctl handler Anthony Krowiak
@ 2026-08-07 22:18 ` Anthony Krowiak
2026-08-07 22:18 ` [PATCH v7 06/15] s390/vfio-ap: Transition guest migration state from STOP to STOP_COPY Anthony Krowiak
` (9 subsequent siblings)
14 siblings, 0 replies; 16+ messages in thread
From: Anthony Krowiak @ 2026-08-07 22:18 UTC (permalink / raw)
To: linux-s390, linux-kernel, kvm
Cc: jjherne, borntraeger, mjrosato, pasic, alex, kwankhede, fiuczy,
pbonzini, frankja, imbrenda, agordeev, hca, gor
Implements two callbacks related to the current state of a vfio-ap device:
* The callback that sets a new migration state of a vfio-ap device during
live migration of guests with pass-through access to AP devices. This
callback is mandatory for VFIO_DEVICE_FEATURE_MIGRATION support.
The function pointer for this callback is specified via the
'migration_set_state' field of the 'vfio_migration_ops' structure
which is stored with the VFIO device when the 'vfio_device'
structure representing the mediated device is initialized.
* The callback that returns the current vfio device migration state during
live migration of guests with pass-through access to AP devices.
The function pointer for this callback is specified via the
'migration_get_state' field of the 'vfio_migration_ops' structure
which is stored with the VFIO device when the 'vfio_device'
structure representing the mediated device is initialized.
Signed-off-by: Anthony Krowiak <akrowiak@linux.ibm.com>
---
drivers/s390/crypto/vfio_ap_migration.c | 130 +++++++++++++++++++++++-
1 file changed, 128 insertions(+), 2 deletions(-)
diff --git a/drivers/s390/crypto/vfio_ap_migration.c b/drivers/s390/crypto/vfio_ap_migration.c
index 1613813124b6..af740b177c97 100644
--- a/drivers/s390/crypto/vfio_ap_migration.c
+++ b/drivers/s390/crypto/vfio_ap_migration.c
@@ -128,16 +128,141 @@ static void vfio_ap_release_resuming_file(struct vfio_ap_migration_data *mig_dat
*/
}
+static struct file *
+vfio_ap_transition_to_state(struct ap_matrix_mdev *matrix_mdev,
+ enum vfio_device_mig_state new_state)
+{
+ struct vfio_ap_migration_data *mig_data;
+ enum vfio_device_mig_state cur_state;
+
+ lockdep_assert_held(&matrix_dev->mdevs_lock);
+ mig_data = matrix_mdev->mig_data;
+ cur_state = mig_data->mig_state;
+ dev_dbg(matrix_mdev->vdev.dev, "%s: %d -> %d\n", __func__, cur_state,
+ new_state);
+
+ if (cur_state == VFIO_DEVICE_STATE_STOP &&
+ new_state == VFIO_DEVICE_STATE_STOP_COPY) {
+ /* TODO */
+ return ERR_PTR(-EOPNOTSUPP);
+ }
+
+ if (cur_state == VFIO_DEVICE_STATE_STOP &&
+ new_state == VFIO_DEVICE_STATE_RESUMING) {
+ /* TODO */
+ return ERR_PTR(-EOPNOTSUPP);
+ }
+
+ if ((cur_state == VFIO_DEVICE_STATE_RESUMING &&
+ new_state == VFIO_DEVICE_STATE_STOP) ||
+ (cur_state == VFIO_DEVICE_STATE_STOP_COPY &&
+ new_state == VFIO_DEVICE_STATE_STOP)) {
+ /* TODO */
+ return ERR_PTR(-EOPNOTSUPP);
+ }
+
+ if ((cur_state == VFIO_DEVICE_STATE_STOP &&
+ new_state == VFIO_DEVICE_STATE_RUNNING) ||
+ (cur_state == VFIO_DEVICE_STATE_RUNNING &&
+ new_state == VFIO_DEVICE_STATE_STOP)) {
+ /* TODO */
+ return ERR_PTR(-EOPNOTSUPP);
+ }
+
+ /* vfio_mig_get_next_state() does not use arcs other than the above */
+ WARN_ON(true);
+
+ return ERR_PTR(-EINVAL);
+}
+
static struct file *vfio_ap_set_state(struct vfio_device *vdev,
enum vfio_device_mig_state new_state)
{
- return NULL;
+ int ret;
+ struct file *filp = NULL;
+ struct ap_matrix_mdev *matrix_mdev;
+ enum vfio_device_mig_state next_state;
+ struct vfio_ap_migration_data *mig_data;
+
+ matrix_mdev = container_of(vdev, struct ap_matrix_mdev, vdev);
+
+ mutex_lock(&matrix_dev->mdevs_lock);
+ if (ap_is_se_guest()) {
+ dev_err_once(matrix_mdev->vdev.dev,
+ "Migration not allowed from or to a Secure Execution guest\n");
+ mutex_unlock(&matrix_dev->mdevs_lock);
+ return ERR_PTR(-EPERM);
+ }
+
+ mig_data = matrix_mdev->mig_data;
+
+ /*
+ * The mig_data pointer is set in the vfio_ap_init_migration_data
+ * function which is called when the vfio-ap device fd is opened.
+ * Since the implicit pre-open state is RUNNING, a request to set
+ * RUNNING is a no-op. Any other state transition is invalid before
+ * open_device.
+ */
+ if (!mig_data) {
+ mutex_unlock(&matrix_dev->mdevs_lock);
+ if (new_state == VFIO_DEVICE_STATE_RUNNING)
+ return NULL;
+ return ERR_PTR(-ENODEV);
+ }
+
+ dev_dbg(vdev->dev, "%s -> %d\n", __func__, new_state);
+
+ while (mig_data->mig_state != VFIO_DEVICE_STATE_ERROR &&
+ mig_data->mig_state != new_state) {
+ ret = vfio_mig_get_next_state(vdev, mig_data->mig_state,
+ new_state, &next_state);
+ if (ret) {
+ filp = ERR_PTR(ret);
+ break;
+ }
+
+ filp = vfio_ap_transition_to_state(matrix_mdev, next_state);
+ if (IS_ERR(filp))
+ break;
+
+ mig_data->mig_state = next_state;
+
+ if (WARN_ON(filp && new_state != next_state)) {
+ fput(filp);
+ filp = ERR_PTR(-EINVAL);
+ break;
+ }
+ }
+
+ mutex_unlock(&matrix_dev->mdevs_lock);
+
+ return filp;
}
static int vfio_ap_get_state(struct vfio_device *vdev,
enum vfio_device_mig_state *current_state)
{
- return -EOPNOTSUPP;
+ struct ap_matrix_mdev *matrix_mdev;
+ struct vfio_ap_migration_data *mig_data;
+
+ mutex_lock(&matrix_dev->mdevs_lock);
+
+ matrix_mdev = container_of(vdev, struct ap_matrix_mdev, vdev);
+ mig_data = matrix_mdev->mig_data;
+
+ /*
+ * The mig_data pointer is set in the vfio_ap_init_migration_data
+ * function which is called when the vfio-ap device fd is opened.
+ * If mig_data is NULL, report RUNNING as the implicit pre-open state
+ * so userspace doesn't need to perform any state transition before the
+ * device becomes active.
+ */
+ *current_state = (mig_data) ? mig_data->mig_state :
+ VFIO_DEVICE_STATE_RUNNING;
+
+ mutex_unlock(&matrix_dev->mdevs_lock);
+
+ return 0;
}
static int vfio_ap_get_data_size(struct vfio_device *vdev,
@@ -159,6 +284,7 @@ static const struct vfio_migration_ops vfio_ap_migration_ops = {
*/
void vfio_ap_init_migration_capabilities(struct ap_matrix_mdev *matrix_mdev)
{
+ /* Live guest migration is not supported for SE guests */
if (ap_is_se_guest())
return;
--
2.53.0
^ permalink raw reply related [flat|nested] 16+ messages in thread* [PATCH v7 06/15] s390/vfio-ap: Transition guest migration state from STOP to STOP_COPY
2026-08-07 22:18 [PATCH v7 00/15] s390/vfio-ap: Add live guest migration support Anthony Krowiak
` (4 preceding siblings ...)
2026-08-07 22:18 ` [PATCH v7 05/15] s390/vfio-ap: Callback to get/set vfio device mig state during guest migration Anthony Krowiak
@ 2026-08-07 22:18 ` Anthony Krowiak
2026-08-07 22:18 ` [PATCH v7 07/15] s390/vfio-ap: File ops called to save the vfio device migration state Anthony Krowiak
` (8 subsequent siblings)
14 siblings, 0 replies; 16+ messages in thread
From: Anthony Krowiak @ 2026-08-07 22:18 UTC (permalink / raw)
To: linux-s390, linux-kernel, kvm
Cc: jjherne, borntraeger, mjrosato, pasic, alex, kwankhede, fiuczy,
pbonzini, frankja, imbrenda, agordeev, hca, gor
The transition of the guest migration state from VFIO_DEVICE_STATE_STOP to
VFIO_DEVICE_STATE_STOP_COPY begins the process of saving the
vfio device state. The vfio device state is comprised of the guest's
AP configuration which specifies the adapters, domains and control
domains to which the guest will be given access.
To begin the process of saving the vfio device state, the VFIO AP device
driver opens a file stream that will be used to read the source guest's
AP configuration.
Note:
This commit introduces the file operations structure for migration state
files with a stub implementation of the read operation. The complete
implementation is provided in the subsequent commit.
This incremental approach allows for easier review of the migration
infrastructure setup separate from the actual implementation logic.
Signed-off-by: Anthony Krowiak <akrowiak@linux.ibm.com>
---
drivers/s390/crypto/vfio_ap_migration.c | 72 ++++++++++++++++++++++++-
1 file changed, 70 insertions(+), 2 deletions(-)
diff --git a/drivers/s390/crypto/vfio_ap_migration.c b/drivers/s390/crypto/vfio_ap_migration.c
index af740b177c97..de693b308925 100644
--- a/drivers/s390/crypto/vfio_ap_migration.c
+++ b/drivers/s390/crypto/vfio_ap_migration.c
@@ -4,6 +4,7 @@
*
* Copyright IBM Corp. 2025
*/
+#include <linux/anon_inodes.h>
#include <linux/file.h>
#include "vfio_ap_private.h"
@@ -128,6 +129,61 @@ static void vfio_ap_release_resuming_file(struct vfio_ap_migration_data *mig_dat
*/
}
+static ssize_t
+vfio_ap_stop_copy_read(struct file *, char __user *, size_t, loff_t *)
+{
+ /* TODO */
+ return -EOPNOTSUPP;
+}
+
+static int vfio_ap_release_mig_file(struct inode *file_inode, struct file *filp)
+{
+ struct ap_matrix_mdev *matrix_mdev = filp->private_data;
+
+ /*
+ * The VFIO device lifetime is tied to migration FD lifetime (see
+ * vfio_ap_open_file_stream() function) to guarantee that the
+ * matrix_mdev remains valid for every read/write operation. Let's drop
+ * it here since the migration FD is being released.
+ */
+ vfio_device_put_registration(&matrix_mdev->vdev);
+ return 0;
+}
+
+static const struct file_operations vfio_ap_stop_copy_fops = {
+ .owner = THIS_MODULE,
+ .read = vfio_ap_stop_copy_read,
+ .compat_ioctl = compat_ptr_ioctl,
+ .release = vfio_ap_release_mig_file,
+};
+
+static struct file *vfio_ap_open_file_stream(struct ap_matrix_mdev *matrix_mdev,
+ const struct file_operations *fops,
+ int flags)
+{
+ struct file *filp;
+
+ lockdep_assert_held(&matrix_dev->mdevs_lock);
+
+ /*
+ * Pin the vfio_device registration so that matrix_mdev cannot be freed
+ * while the migration FD is still open. The matching put is in
+ * vfio_ap_release_mig_file().
+ */
+ if (!vfio_device_try_get_registration(&matrix_mdev->vdev))
+ return ERR_PTR(-ENODEV);
+
+ filp = anon_inode_getfile("vfio_ap_mig_file", fops, matrix_mdev, flags);
+ if (IS_ERR(filp)) {
+ vfio_device_put_registration(&matrix_mdev->vdev);
+ return filp;
+ }
+
+ stream_open(filp->f_inode, filp);
+
+ return filp;
+}
+
static struct file *
vfio_ap_transition_to_state(struct ap_matrix_mdev *matrix_mdev,
enum vfio_device_mig_state new_state)
@@ -141,10 +197,22 @@ vfio_ap_transition_to_state(struct ap_matrix_mdev *matrix_mdev,
dev_dbg(matrix_mdev->vdev.dev, "%s: %d -> %d\n", __func__, cur_state,
new_state);
+ /*
+ * Begins the process of saving the vfio device state by creating and
+ * returning a streaming data_fd to be used to read out the internal
+ * state of the vfio-ap device on the source host.
+ */
if (cur_state == VFIO_DEVICE_STATE_STOP &&
new_state == VFIO_DEVICE_STATE_STOP_COPY) {
- /* TODO */
- return ERR_PTR(-EOPNOTSUPP);
+ struct file *filp = vfio_ap_open_file_stream(matrix_mdev,
+ &vfio_ap_stop_copy_fops,
+ O_RDONLY);
+ if (IS_ERR(filp))
+ return ERR_CAST(filp);
+
+ mig_data->stop_copy_mig_file.filp = filp;
+
+ return filp;
}
if (cur_state == VFIO_DEVICE_STATE_STOP &&
--
2.53.0
^ permalink raw reply related [flat|nested] 16+ messages in thread* [PATCH v7 07/15] s390/vfio-ap: File ops called to save the vfio device migration state
2026-08-07 22:18 [PATCH v7 00/15] s390/vfio-ap: Add live guest migration support Anthony Krowiak
` (5 preceding siblings ...)
2026-08-07 22:18 ` [PATCH v7 06/15] s390/vfio-ap: Transition guest migration state from STOP to STOP_COPY Anthony Krowiak
@ 2026-08-07 22:18 ` Anthony Krowiak
2026-08-07 22:18 ` [PATCH v7 08/15] s390/vfio-ap: Transition device migration state from STOP to RESUMING Anthony Krowiak
` (7 subsequent siblings)
14 siblings, 0 replies; 16+ messages in thread
From: Anthony Krowiak @ 2026-08-07 22:18 UTC (permalink / raw)
To: linux-s390, linux-kernel, kvm
Cc: jjherne, borntraeger, mjrosato, pasic, alex, kwankhede, fiuczy,
pbonzini, frankja, imbrenda, agordeev, hca, gor
Implements the read callback function that was added to the
file_operations structure for the file created to save the state of the
vfio-ap device when the migration state transitioned from STOP to
to the STOP_COPY state.
This function copies the guest's AP configuration information to
userspace. The information copied is comprised of the APQN of each queue
device passed through to the guest along with its hardware information.
This state data will be transferred to the vfio_ap device driver on the
destination host when the state is transitioned to RESUMING.
Signed-off-by: Anthony Krowiak <akrowiak@linux.ibm.com>
---
drivers/s390/crypto/vfio_ap_migration.c | 287 +++++++++++++++++++++++-
1 file changed, 277 insertions(+), 10 deletions(-)
diff --git a/drivers/s390/crypto/vfio_ap_migration.c b/drivers/s390/crypto/vfio_ap_migration.c
index de693b308925..50781b61f7f1 100644
--- a/drivers/s390/crypto/vfio_ap_migration.c
+++ b/drivers/s390/crypto/vfio_ap_migration.c
@@ -117,9 +117,10 @@ struct vfio_ap_config {
static void
vfio_ap_release_stop_copy_file(struct vfio_ap_migration_data *mig_data)
{
- /* Stub to be implemented when the mig_data->stop_copy_mig_file.ap_config
- * object is allocated.
- */
+ kvfree(mig_data->stop_copy_mig_file.ap_config);
+ mig_data->stop_copy_mig_file.ap_config = NULL;
+ mig_data->stop_copy_mig_file.config_sz = 0;
+ mig_data->stop_copy_mig_file.filp = NULL;
}
static void vfio_ap_release_resuming_file(struct vfio_ap_migration_data *mig_data)
@@ -129,13 +130,6 @@ static void vfio_ap_release_resuming_file(struct vfio_ap_migration_data *mig_dat
*/
}
-static ssize_t
-vfio_ap_stop_copy_read(struct file *, char __user *, size_t, loff_t *)
-{
- /* TODO */
- return -EOPNOTSUPP;
-}
-
static int vfio_ap_release_mig_file(struct inode *file_inode, struct file *filp)
{
struct ap_matrix_mdev *matrix_mdev = filp->private_data;
@@ -150,6 +144,279 @@ static int vfio_ap_release_mig_file(struct inode *file_inode, struct file *filp)
return 0;
}
+/**
+ * validate_stop_copy_read_parms: Validate the input parameters to the
+ * vfio_ap_stop_copy_read function
+ *
+ * @matrix_mdev: The object device containing the state to be read
+ * @filp: Pointer to the file stream used to read the vfio-ap device state
+ * @pos: The file offset from which to start reading data
+ * @len: The length of the data to be read
+ *
+ * Verify the following:
+ * - @filp private data is an ap_matrix_mdev instance
+ * - @filp is the instance opened when state transitioned from STOP to STOP_COPY
+ * - @pos + @len does not cause integer overflow
+ *
+ * Returns: 0 if the parameters pass validation; otherwise returns an error
+ */
+static int validate_stop_copy_read_parms(struct file *filp, loff_t *pos,
+ size_t len)
+{
+ struct vfio_ap_migration_data *mig_data;
+ struct ap_matrix_mdev *matrix_mdev;
+ loff_t total_len;
+
+ lockdep_assert_held(&matrix_dev->mdevs_lock);
+
+ if (check_add_overflow((loff_t)len, *pos, &total_len))
+ return -EIO;
+
+ /*
+ * matrix_mdev is guaranteed live here: vfio_ap_open_file_stream() took
+ * a vfio_device registration reference that is held until
+ * vfio_ap_release_mig_file() runs, so the embedding matrix_mdev cannot
+ * be freed while this file descriptor is open.
+ */
+ matrix_mdev = filp->private_data;
+
+ if (!matrix_mdev->mig_data)
+ return -ENODEV;
+
+ mig_data = matrix_mdev->mig_data;
+
+ if (mig_data->stop_copy_mig_file.filp != filp)
+ return -EINVAL;
+
+ return 0;
+}
+
+static size_t vfio_ap_config_size(struct ap_matrix_mdev *matrix_mdev,
+ int *num_queues)
+{
+ size_t qinfo_size;
+
+ lockdep_assert_held(&matrix_dev->mdevs_lock);
+
+ *num_queues = vfio_ap_mdev_get_num_queues(&matrix_mdev->shadow_apcb);
+ qinfo_size = *num_queues * sizeof(struct vfio_ap_queue_info);
+
+ return qinfo_size + sizeof(struct vfio_ap_config);
+}
+
+static int get_hardware_info_for_queue(const char *mdev_name,
+ struct ap_tapq_hwinfo *hwinfo,
+ unsigned long apqn)
+{
+ struct ap_queue_status status;
+
+ status = ap_tapq(apqn, hwinfo);
+
+ switch (status.response_code) {
+ case AP_RESPONSE_NORMAL:
+ case AP_RESPONSE_RESET_IN_PROGRESS:
+ case AP_RESPONSE_DECONFIGURED:
+ case AP_RESPONSE_CHECKSTOPPED:
+ case AP_RESPONSE_BUSY:
+ /* For all these RCs the tapq info should be available */
+ return 0;
+ case AP_RESPONSE_Q_NOT_AVAIL:
+ pr_err_ratelimited("vfio_ap_mdev %s: Failed to get hwinfo for queue %02lx.%04lx: TAPQ rc=%d",
+ mdev_name, AP_QID_CARD(apqn), AP_QID_QUEUE(apqn),
+ status.response_code);
+ return -ENODEV;
+ default:
+ /*
+ * Without a pending async error, the tapq info should be
+ * available
+ */
+ if (status.async)
+ return 0;
+
+ pr_err_ratelimited("vfio_ap_mdev %s:Failed to get hwinfo for queue %02lx.%04lx: TAPQ rc=%d",
+ mdev_name, AP_QID_CARD(apqn), AP_QID_QUEUE(apqn),
+ status.response_code);
+ return -EIO;
+ }
+}
+
+/**
+ * vfio_ap_store_queue_info:
+ *
+ * Stores the hardware information returned from the PQAP(TAPQ) command for each
+ * queue device identified in the 'qinfo' field of the a vfio_ap_config
+ * object. If there are a large number of queues for which hardware information
+ * must be retrieved, this function must be called without the mdevs_lock
+ * held. This should not be a problem since the APQNs in the 'qinfo' field
+ * should already have been snapshotted prior to calling this function.
+ *
+ * @mdev_name: The name (UUID) of the mediated device to use in log messages
+ * @ap_config: A reference to the vfio_ap_config instance in which to store
+ * the queue information. It is expected that each APQN identifying
+ * a queue device for which hardware information is to be retrieved
+ * shall be snapshotted prior to calling this function.
+ *
+ * Returns: Zero (0) if the hardware information is retrieved for each queue
+ * device in the AP configuration; otherwise, returns an error.
+ */
+static int vfio_ap_store_queue_info(const char *mdev_name,
+ struct vfio_ap_config *ap_config)
+{
+ struct ap_tapq_hwinfo source_hwinfo;
+ unsigned long num_queues;
+ int ret;
+
+ for (num_queues = 0; num_queues < ap_config->num_queues; num_queues++) {
+ ret = get_hardware_info_for_queue(mdev_name, &source_hwinfo,
+ ap_config->qinfo[num_queues].apqn);
+ if (ret)
+ return ret;
+
+ ap_config->qinfo[num_queues].data = source_hwinfo.value;
+ }
+
+ return 0;
+}
+
+static int vfio_ap_get_config(struct ap_matrix_mdev *matrix_mdev)
+{
+ struct vfio_ap_config *ap_configuration;
+ unsigned long *apm, *aqm, apid, apqi;
+ const char *mdev_name;
+ size_t ap_config_size;
+ int ret, num_queues;
+
+ lockdep_assert_held(&matrix_dev->mdevs_lock);
+
+ ap_config_size = vfio_ap_config_size(matrix_mdev, (int *)&num_queues);
+
+ ap_configuration = kvzalloc(ap_config_size, GFP_KERNEL_ACCOUNT);
+ if (!ap_configuration)
+ return -ENOMEM;
+
+ ap_configuration->magic = VFIO_AP_MIG_MAGIC;
+ ap_configuration->version = VFIO_AP_MIG_VERSION;
+
+ /*
+ * num_queues must be set before writing qinfo[] elements; the
+ * __counted_by(num_queues) annotation on qinfo[] causes the compiler to
+ * insert bounds checks that evaluate against ap_configuration->num_queues.
+ * Writing through qinfo[i] with num_queues still 0 would trap.
+ */
+ ap_configuration->num_queues = num_queues;
+
+ apm = matrix_mdev->shadow_apcb.apm;
+ aqm = matrix_mdev->shadow_apcb.aqm;
+ num_queues = 0;
+ for_each_set_bit_inv(apid, apm, AP_DEVICES) {
+ for_each_set_bit_inv(apqi, aqm, AP_DOMAINS) {
+ ap_configuration->qinfo[num_queues].apqn =
+ AP_MKQID(apid, apqi);
+ num_queues += 1;
+ }
+ }
+ memcpy(ap_configuration->adm, matrix_mdev->shadow_apcb.adm,
+ sizeof(ap_configuration->adm));
+ mdev_name = dev_name(matrix_mdev->vdev.dev);
+
+ /*
+ * Unlock the mdevs_lock so other mdevs are not precluded from being
+ * accessed while a potentially long running operation is performed.
+ */
+ mutex_unlock(&matrix_dev->mdevs_lock);
+ ret = vfio_ap_store_queue_info(mdev_name, ap_configuration);
+ mutex_lock(&matrix_dev->mdevs_lock);
+ if (ret) {
+ kvfree(ap_configuration);
+ return ret;
+ }
+
+ if (!matrix_mdev->mig_data) {
+ kvfree(ap_configuration);
+ return -ENODEV;
+ }
+
+ matrix_mdev->mig_data->stop_copy_mig_file.ap_config = ap_configuration;
+ matrix_mdev->mig_data->stop_copy_mig_file.config_sz = ap_config_size;
+
+ return 0;
+}
+
+static ssize_t vfio_ap_stop_copy_read(struct file *filp, char __user *buf,
+ size_t len, loff_t *pos)
+{
+ struct vfio_ap_migration_file *mig_file;
+ struct ap_matrix_mdev *matrix_mdev;
+ loff_t read_pos;
+ ssize_t ret;
+
+ /*
+ * This file was opened with stream_open(), so pos should be NULL for
+ * sequential read() calls; a non-NULL pointer will be passed only
+ * for positional pread() calls in which case we return an error
+ * indicating broken pipe/illegal seek on a non-seekable file
+ */
+ if (pos)
+ return -ESPIPE;
+
+ mutex_lock(&matrix_dev->mdevs_lock);
+
+ pos = &filp->f_pos;
+
+ ret = validate_stop_copy_read_parms(filp, pos, len);
+ if (ret) {
+ mutex_unlock(&matrix_dev->mdevs_lock);
+ return ret;
+ }
+
+ matrix_mdev = filp->private_data;
+ mig_file = &matrix_mdev->mig_data->stop_copy_mig_file;
+
+ if (!mig_file->ap_config) {
+ ret = vfio_ap_get_config(matrix_mdev);
+ if (ret) {
+ mutex_unlock(&matrix_dev->mdevs_lock);
+ return ret;
+ }
+ }
+
+ /*
+ * Compute the offset and clamped length fully under the lock so that
+ * concurrent read()s on this stream file each see a consistent view of
+ * the current position. *pos is advanced here while we still hold the
+ * lock; copy_to_user() then uses the snapshot read_pos. This prevents
+ * two threads from calculating the same offset and both copying the
+ * same region (or one reading past the end of the buffer).
+ */
+ if (*pos >= mig_file->config_sz) {
+ mutex_unlock(&matrix_dev->mdevs_lock);
+ return 0;
+ }
+
+ len = min_t(size_t, mig_file->config_sz - *pos, len);
+ if (len == 0) {
+ mutex_unlock(&matrix_dev->mdevs_lock);
+ return 0;
+ }
+
+ read_pos = *pos;
+ *pos += len;
+
+ /*
+ * Drop the lock only for the copy_to_user(). The ap_config buffer is
+ * stable: it is allocated once in vfio_ap_get_config() and freed only
+ * in vfio_ap_release_stop_copy_file() which requires mdevs_lock.
+ * Since we already advanced *pos above, no other thread will compute an
+ * overlapping region.
+ */
+ mutex_unlock(&matrix_dev->mdevs_lock);
+
+ if (copy_to_user(buf, (char *)mig_file->ap_config + read_pos, len))
+ return -EFAULT;
+
+ return len;
+}
+
static const struct file_operations vfio_ap_stop_copy_fops = {
.owner = THIS_MODULE,
.read = vfio_ap_stop_copy_read,
--
2.53.0
^ permalink raw reply related [flat|nested] 16+ messages in thread* [PATCH v7 08/15] s390/vfio-ap: Transition device migration state from STOP to RESUMING
2026-08-07 22:18 [PATCH v7 00/15] s390/vfio-ap: Add live guest migration support Anthony Krowiak
` (6 preceding siblings ...)
2026-08-07 22:18 ` [PATCH v7 07/15] s390/vfio-ap: File ops called to save the vfio device migration state Anthony Krowiak
@ 2026-08-07 22:18 ` Anthony Krowiak
2026-08-07 22:18 ` [PATCH v7 09/15] s390/vfio-ap: Add method to set a new guest AP configuration Anthony Krowiak
` (6 subsequent siblings)
14 siblings, 0 replies; 16+ messages in thread
From: Anthony Krowiak @ 2026-08-07 22:18 UTC (permalink / raw)
To: linux-s390, linux-kernel, kvm
Cc: jjherne, borntraeger, mjrosato, pasic, alex, kwankhede, fiuczy,
pbonzini, frankja, imbrenda, agordeev, hca, gor
Transitioning from VFIO_DEVICE_STATE_STOP to VFIO_DEVICE_STATE_RESUMING
starts a process of restoring the device state of the vfio device on the
target system. To prepare for restoring the device state, open a file
stream to receive the guest's AP configuration saved when the device state
on the source system transitioned from VFIO_DEVICE_STATE_STOP to
VFIO_DEVICE_STATE_STOP_COPY.
Note:
This commit introduces the file operations structure for migration state
files with a stub implementation of the write operation. The complete
implementation is provided in the subsequent commit.
This incremental approach allows for easier review of the migration
infrastructure setup separate from the actual implementation logic.
Signed-off-by: Anthony Krowiak <akrowiak@linux.ibm.com>
---
drivers/s390/crypto/vfio_ap_migration.c | 34 +++++++++++++++++++++++--
1 file changed, 32 insertions(+), 2 deletions(-)
diff --git a/drivers/s390/crypto/vfio_ap_migration.c b/drivers/s390/crypto/vfio_ap_migration.c
index 50781b61f7f1..e2e7ae8515e5 100644
--- a/drivers/s390/crypto/vfio_ap_migration.c
+++ b/drivers/s390/crypto/vfio_ap_migration.c
@@ -451,6 +451,26 @@ static struct file *vfio_ap_open_file_stream(struct ap_matrix_mdev *matrix_mdev,
return filp;
}
+static ssize_t vfio_ap_resuming_write(struct file *filp, const char __user *buf,
+ size_t len, loff_t *pos)
+{
+ /* TODO */
+ return -EOPNOTSUPP;
+}
+
+static const struct file_operations vfio_ap_resume_fops = {
+ .owner = THIS_MODULE,
+ .write = vfio_ap_resuming_write,
+ .release = vfio_ap_release_mig_file,
+};
+
+static struct file *vfio_ap_resuming_init(struct ap_matrix_mdev *matrix_mdev)
+{
+ lockdep_assert_held(&matrix_dev->mdevs_lock);
+
+ return vfio_ap_open_file_stream(matrix_mdev, &vfio_ap_resume_fops, O_WRONLY);
+}
+
static struct file *
vfio_ap_transition_to_state(struct ap_matrix_mdev *matrix_mdev,
enum vfio_device_mig_state new_state)
@@ -482,10 +502,20 @@ vfio_ap_transition_to_state(struct ap_matrix_mdev *matrix_mdev,
return filp;
}
+ /*
+ * Begins the process of restoring the vfio device state by creating and
+ * returning a streaming data_fd to be used to read in the internal
+ * state of the vfio-ap device on the destination host.
+ */
if (cur_state == VFIO_DEVICE_STATE_STOP &&
new_state == VFIO_DEVICE_STATE_RESUMING) {
- /* TODO */
- return ERR_PTR(-EOPNOTSUPP);
+ struct file *filp = vfio_ap_resuming_init(matrix_mdev);
+
+ if (IS_ERR(filp))
+ return ERR_CAST(filp);
+
+ mig_data->resuming_mig_file.filp = filp;
+ return filp;
}
if ((cur_state == VFIO_DEVICE_STATE_RESUMING &&
--
2.53.0
^ permalink raw reply related [flat|nested] 16+ messages in thread* [PATCH v7 09/15] s390/vfio-ap: Add method to set a new guest AP configuration
2026-08-07 22:18 [PATCH v7 00/15] s390/vfio-ap: Add live guest migration support Anthony Krowiak
` (7 preceding siblings ...)
2026-08-07 22:18 ` [PATCH v7 08/15] s390/vfio-ap: Transition device migration state from STOP to RESUMING Anthony Krowiak
@ 2026-08-07 22:18 ` Anthony Krowiak
2026-08-07 22:18 ` [PATCH v7 10/15] s390/vfio-ap: File ops called to resume the vfio device migration Anthony Krowiak
` (5 subsequent siblings)
14 siblings, 0 replies; 16+ messages in thread
From: Anthony Krowiak @ 2026-08-07 22:18 UTC (permalink / raw)
To: linux-s390, linux-kernel, kvm
Cc: jjherne, borntraeger, mjrosato, pasic, alex, kwankhede, fiuczy,
pbonzini, frankja, imbrenda, agordeev, hca, gor
Adds a new vfio_ap_set_new_config function to set a guest's AP
configuration. This is needed in order to set the state of the mdev when
it is migrated from a remote host system during the RESUMING phase.
Key changes:
* Refactored code from the ap_config_store function - handles changes to
the sysfs ap_config attribute - into a new, non-static function which
is callable from the ap_config_store function as well as the live guest
migration code.
Signed-off-by: Anthony Krowiak <akrowiak@linux.ibm.com>
---
drivers/s390/crypto/vfio_ap_ops.c | 221 ++++++++++++++------------
drivers/s390/crypto/vfio_ap_private.h | 61 +++++++
2 files changed, 184 insertions(+), 98 deletions(-)
diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index d05372b50d2f..0f33f5189153 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -81,53 +81,6 @@ static inline void release_update_locks_for_kvm(struct kvm *kvm)
mutex_unlock(&matrix_dev->guests_lock);
}
-/**
- * get_update_locks_for_mdev: Acquire the locks required to dynamically update a
- * KVM guest's APCB in the proper order.
- *
- * @matrix_mdev: a pointer to a struct ap_matrix_mdev object containing the AP
- * configuration data to use to update a KVM guest's APCB.
- *
- * The proper locking order is:
- * 1. matrix_dev->guests_lock: required to use the KVM pointer to update a KVM
- * guest's APCB.
- * 2. matrix_mdev->kvm->lock: required to update a guest's APCB
- * 3. matrix_dev->mdevs_lock: required to access data stored in a matrix_mdev
- *
- * Note: If @matrix_mdev is NULL or is not attached to a KVM guest, the KVM
- * lock will not be taken.
- */
-static inline void get_update_locks_for_mdev(struct ap_matrix_mdev *matrix_mdev)
-{
- mutex_lock(&matrix_dev->guests_lock);
- if (matrix_mdev && matrix_mdev->kvm)
- mutex_lock(&matrix_mdev->kvm->lock);
- mutex_lock(&matrix_dev->mdevs_lock);
-}
-
-/**
- * release_update_locks_for_mdev: Release the locks used to dynamically update a
- * KVM guest's APCB in the proper order.
- *
- * @matrix_mdev: a pointer to a struct ap_matrix_mdev object containing the AP
- * configuration data to use to update a KVM guest's APCB.
- *
- * The proper unlocking order is:
- * 1. matrix_dev->mdevs_lock
- * 2. matrix_mdev->kvm->lock
- * 3. matrix_dev->guests_lock
- *
- * Note: If @matrix_mdev is NULL or is not attached to a KVM guest, the KVM
- * lock will not be released.
- */
-static inline void release_update_locks_for_mdev(struct ap_matrix_mdev *matrix_mdev)
-{
- mutex_unlock(&matrix_dev->mdevs_lock);
- if (matrix_mdev && matrix_mdev->kvm)
- mutex_unlock(&matrix_mdev->kvm->lock);
- mutex_unlock(&matrix_dev->guests_lock);
-}
-
/**
* get_update_locks_by_apqn: Find the mdev to which an APQN is assigned and
* acquire the locks required to update the APCB of
@@ -642,8 +595,7 @@ static int handle_pqap(struct kvm_vcpu *vcpu)
return 0;
}
-static void vfio_ap_matrix_init(struct ap_config_info *info,
- struct ap_matrix *matrix)
+void vfio_ap_matrix_init(struct ap_config_info *info, struct ap_matrix *matrix)
{
matrix->apm_max = info->apxa ? info->na : 63;
matrix->aqm_max = info->apxa ? info->nd : 15;
@@ -1018,13 +970,12 @@ static void vfio_ap_mdev_link_adapter(struct ap_matrix_mdev *matrix_mdev,
unsigned long apqi;
for_each_set_bit_inv(apqi, matrix_mdev->matrix.aqm, AP_DOMAINS)
- vfio_ap_mdev_link_apqn(matrix_mdev,
- AP_MKQID(apid, apqi));
+ vfio_ap_mdev_link_apqn(matrix_mdev, AP_MKQID(apid, apqi));
}
-static void collect_queues_to_reset(struct ap_matrix_mdev *matrix_mdev,
- unsigned long apid,
- struct list_head *qlist)
+static void collect_queues_by_apid(struct ap_matrix_mdev *matrix_mdev,
+ unsigned long apid,
+ struct list_head *qlist)
{
struct vfio_ap_queue *q;
unsigned long apqi;
@@ -1042,7 +993,7 @@ static void reset_queues_for_apid(struct ap_matrix_mdev *matrix_mdev,
struct list_head qlist;
INIT_LIST_HEAD(&qlist);
- collect_queues_to_reset(matrix_mdev, apid, &qlist);
+ collect_queues_by_apid(matrix_mdev, apid, &qlist);
vfio_ap_mdev_reset_qlist(&qlist);
}
@@ -1058,7 +1009,7 @@ static int reset_queues_for_apids(struct ap_matrix_mdev *matrix_mdev,
INIT_LIST_HEAD(&qlist);
for_each_set_bit_inv(apid, apm_reset, AP_DEVICES)
- collect_queues_to_reset(matrix_mdev, apid, &qlist);
+ collect_queues_by_apid(matrix_mdev, apid, &qlist);
return vfio_ap_mdev_reset_qlist(&qlist);
}
@@ -1729,54 +1680,100 @@ static void ap_matrix_copy(struct ap_matrix *dst, struct ap_matrix *src)
bitmap_copy(dst->adm, src->adm, AP_DOMAINS);
}
-static ssize_t ap_config_store(struct device *dev, struct device_attribute *attr,
- const char *buf, size_t count)
+static void get_removed_matrixes(struct ap_matrix *m_removed,
+ struct ap_matrix *m_old,
+ struct ap_matrix *m_new)
{
- struct ap_matrix_mdev *matrix_mdev = dev_get_drvdata(dev);
- struct ap_matrix m_new, m_old, m_added, m_removed;
+ bitmap_andnot(m_removed->apm, m_old->apm, m_new->apm, AP_DEVICES);
+ bitmap_andnot(m_removed->aqm, m_old->aqm, m_new->aqm, AP_DOMAINS);
+ bitmap_andnot(m_removed->adm, m_old->adm, m_new->adm, AP_DOMAINS);
+}
+
+static void get_added_matrixes(struct ap_matrix *m_added,
+ struct ap_matrix *m_old,
+ struct ap_matrix *m_new)
+{
+ bitmap_andnot(m_added->apm, m_new->apm, m_old->apm, AP_DEVICES);
+ bitmap_andnot(m_added->aqm, m_new->aqm, m_old->aqm, AP_DOMAINS);
+ bitmap_andnot(m_added->adm, m_new->adm, m_old->adm, AP_DOMAINS);
+}
+
+static int validate_new_state(struct ap_matrix_mdev *matrix_mdev)
+{
+ int rc;
+
+ /* Ensure new state is valid, else undo new state */
+ rc = vfio_ap_mdev_validate_masks(matrix_mdev);
+ if (rc)
+ return rc;
+
+ rc = ap_matrix_overflow_check(matrix_mdev);
+ if (rc)
+ return rc;
+
+ return 0;
+}
+
+static void link_new_queues(struct ap_matrix_mdev *matrix_mdev,
+ struct ap_matrix *m_added)
+{
+ unsigned long apid, apqi;
+
+ for_each_set_bit_inv(apid, m_added->apm, AP_DEVICES)
+ vfio_ap_mdev_link_adapter(matrix_mdev, apid);
+
+ for_each_set_bit_inv(apqi, m_added->aqm, AP_DOMAINS)
+ vfio_ap_mdev_link_domain(matrix_mdev, apqi);
+}
+
+/**
+ * vfio_ap_set_new_guest_config:
+ *
+ * Set a new AP configuration for a guest.
+ *
+ * @matrix_mdev: Object used to maintain the AP configuration for a guest
+ * @m_new: Object used to set the new AP configuration
+ *
+ * Returns: zero (0) if the new AP configuration is successfully set; otherwise,
+ * returns an error:
+ *
+ * ~ EADDRNOTAVAIL One or more APQNs are reserved for host use
+ * ~ EADDRINUSE One or more APQNs are assigned to another mdev
+ * ~ ENODEV An adapter, domain or control domain in the new
+ * AP configuration exceeds the max architected value
+ */
+int vfio_ap_set_new_guest_config(struct ap_matrix_mdev *matrix_mdev,
+ struct ap_matrix *m_new)
+{
+ struct ap_matrix m_old, m_old_shadow, m_added, m_removed;
DECLARE_BITMAP(apm_filtered, AP_DEVICES);
- unsigned long newbit;
- char *newbuf, *rest;
- int rc = count;
bool do_update;
+ int rc;
- newbuf = kstrndup(buf, AP_CONFIG_STRLEN, GFP_KERNEL);
- if (!newbuf)
- return -ENOMEM;
- rest = newbuf;
+ lockdep_assert_held(&ap_attr_mutex);
+ assert_has_update_locks_for_mdev(matrix_mdev);
- mutex_lock(&ap_attr_mutex);
- get_update_locks_for_mdev(matrix_mdev);
-
- /* Save old state */
+ /* Save the old state */
ap_matrix_copy(&m_old, &matrix_mdev->matrix);
- if (parse_bitmap(&rest, m_new.apm, AP_DEVICES) ||
- parse_bitmap(&rest, m_new.aqm, AP_DOMAINS) ||
- parse_bitmap(&rest, m_new.adm, AP_DOMAINS)) {
- rc = -EINVAL;
- goto out;
- }
+ ap_matrix_copy(&m_old_shadow, &matrix_mdev->shadow_apcb);
- bitmap_andnot(m_removed.apm, m_old.apm, m_new.apm, AP_DEVICES);
- bitmap_andnot(m_removed.aqm, m_old.aqm, m_new.aqm, AP_DOMAINS);
- bitmap_andnot(m_added.apm, m_new.apm, m_old.apm, AP_DEVICES);
- bitmap_andnot(m_added.aqm, m_new.aqm, m_old.aqm, AP_DOMAINS);
+ /*
+ * Get the adapters, domains and control domains added and/or removed
+ * from the existing configuration
+ */
+ get_removed_matrixes(&m_removed, &m_old, m_new);
+ get_added_matrixes(&m_added, &m_old, m_new);
/* Need new bitmaps in matrix_mdev for validation */
- ap_matrix_copy(&matrix_mdev->matrix, &m_new);
+ ap_matrix_copy(&matrix_mdev->matrix, m_new);
/* Ensure new state is valid, else undo new state */
- rc = vfio_ap_mdev_validate_masks(matrix_mdev);
- if (rc) {
- ap_matrix_copy(&matrix_mdev->matrix, &m_old);
- goto out;
- }
- rc = ap_matrix_overflow_check(matrix_mdev);
+ rc = validate_new_state(matrix_mdev);
if (rc) {
ap_matrix_copy(&matrix_mdev->matrix, &m_old);
- goto out;
+ ap_matrix_copy(&matrix_mdev->shadow_apcb, &m_old_shadow);
+ return rc;
}
- rc = count;
/* Need old bitmaps in matrix_mdev for unplug/unlink */
ap_matrix_copy(&matrix_mdev->matrix, &m_old);
@@ -1786,14 +1783,10 @@ static ssize_t ap_config_store(struct device *dev, struct device_attribute *attr
vfio_ap_mdev_hot_unplug_domains(matrix_mdev, m_removed.aqm);
/* Need new bitmaps in matrix_mdev for linking new adapters/domains */
- ap_matrix_copy(&matrix_mdev->matrix, &m_new);
-
- /* Link newly added adapters */
- for_each_set_bit_inv(newbit, m_added.apm, AP_DEVICES)
- vfio_ap_mdev_link_adapter(matrix_mdev, newbit);
+ ap_matrix_copy(&matrix_mdev->matrix, m_new);
- for_each_set_bit_inv(newbit, m_added.aqm, AP_DOMAINS)
- vfio_ap_mdev_link_domain(matrix_mdev, newbit);
+ /* Link queues associated with the newly added adapters and domains */
+ link_new_queues(matrix_mdev, &m_added);
/* filter resources not bound to vfio-ap */
do_update = vfio_ap_mdev_filter_matrix(matrix_mdev, apm_filtered);
@@ -1804,7 +1797,39 @@ static ssize_t ap_config_store(struct device *dev, struct device_attribute *attr
vfio_ap_mdev_update_guest_apcb(matrix_mdev);
reset_queues_for_apids(matrix_mdev, apm_filtered);
}
-out:
+
+ return 0;
+}
+
+static ssize_t ap_config_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct ap_matrix_mdev *matrix_mdev = dev_get_drvdata(dev);
+ struct ap_matrix m_new;
+ char *newbuf, *rest;
+ ssize_t rc;
+
+ newbuf = kstrndup(buf, AP_CONFIG_STRLEN, GFP_KERNEL);
+ if (!newbuf)
+ return -ENOMEM;
+ rest = newbuf;
+
+ mutex_lock(&ap_attr_mutex);
+ get_update_locks_for_mdev(matrix_mdev);
+
+ if (parse_bitmap(&rest, m_new.apm, AP_DEVICES) ||
+ parse_bitmap(&rest, m_new.aqm, AP_DOMAINS) ||
+ parse_bitmap(&rest, m_new.adm, AP_DOMAINS)) {
+ kfree(newbuf);
+ release_update_locks_for_mdev(matrix_mdev);
+ mutex_unlock(&ap_attr_mutex);
+ return -EINVAL;
+ }
+
+ rc = vfio_ap_set_new_guest_config(matrix_mdev, &m_new);
+ if (!rc)
+ rc = count;
+
release_update_locks_for_mdev(matrix_mdev);
mutex_unlock(&ap_attr_mutex);
kfree(newbuf);
diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h
index 1fbdfcce5a11..150dfce8a674 100644
--- a/drivers/s390/crypto/vfio_ap_private.h
+++ b/drivers/s390/crypto/vfio_ap_private.h
@@ -157,6 +157,62 @@ struct vfio_ap_queue {
struct work_struct reset_work;
};
+/**
+ * get_update_locks_for_mdev: Acquire the locks required to dynamically update a
+ * KVM guest's APCB in the proper order.
+ *
+ * @matrix_mdev: a pointer to a struct ap_matrix_mdev object containing the AP
+ * configuration data to use to update a KVM guest's APCB.
+ *
+ * The proper locking order is:
+ * 1. matrix_dev->guests_lock: required to use the KVM pointer to update a KVM
+ * guest's APCB.
+ * 2. matrix_mdev->kvm->lock: required to update a guest's APCB
+ * 3. matrix_dev->mdevs_lock: required to access data stored in a matrix_mdev
+ *
+ * Note: If @matrix_mdev is NULL or is not attached to a KVM guest, the KVM
+ * lock will not be taken.
+ */
+static inline void get_update_locks_for_mdev(struct ap_matrix_mdev *matrix_mdev)
+{
+ mutex_lock(&matrix_dev->guests_lock);
+ if (matrix_mdev && matrix_mdev->kvm)
+ mutex_lock(&matrix_mdev->kvm->lock);
+ mutex_lock(&matrix_dev->mdevs_lock);
+}
+
+/**
+ * release_update_locks_for_mdev: Release the locks used to dynamically update a
+ * KVM guest's APCB in the proper order.
+ *
+ * @matrix_mdev: a pointer to a struct ap_matrix_mdev object containing the AP
+ * configuration data to use to update a KVM guest's APCB.
+ *
+ * The proper unlocking order is:
+ * 1. matrix_dev->mdevs_lock
+ * 2. matrix_mdev->kvm->lock
+ * 3. matrix_dev->guests_lock
+ *
+ * Note: If @matrix_mdev is NULL or is not attached to a KVM guest, the KVM
+ * lock will not be released.
+ */
+static inline void release_update_locks_for_mdev(struct ap_matrix_mdev *matrix_mdev)
+{
+ mutex_unlock(&matrix_dev->mdevs_lock);
+ if (matrix_mdev && matrix_mdev->kvm)
+ mutex_unlock(&matrix_mdev->kvm->lock);
+ mutex_unlock(&matrix_dev->guests_lock);
+}
+
+static inline void
+assert_has_update_locks_for_mdev(struct ap_matrix_mdev *matrix_mdev)
+{
+ lockdep_assert_held(&matrix_dev->guests_lock);
+ if (matrix_mdev && matrix_mdev->kvm)
+ lockdep_assert_held(&matrix_mdev->kvm->lock);
+ lockdep_assert_held(&matrix_dev->mdevs_lock);
+}
+
int vfio_ap_mdev_get_num_queues(struct ap_matrix *ap_matrix);
int vfio_ap_mdev_register(void);
@@ -172,9 +228,14 @@ void vfio_ap_on_cfg_changed(struct ap_config_info *new_config_info,
void vfio_ap_on_scan_complete(struct ap_config_info *new_config_info,
struct ap_config_info *old_config_info);
+void vfio_ap_matrix_init(struct ap_config_info *info, struct ap_matrix *matrix);
+
void vfio_ap_init_migration_capabilities(struct ap_matrix_mdev *matrix_mdev);
int vfio_ap_init_migration_data(struct ap_matrix_mdev *matrix_mdev);
void vfio_ap_release_migration_data(struct ap_matrix_mdev *matrix_mdev);
void vfio_ap_reset_migration_state(struct ap_matrix_mdev *matrix_mdev);
+int vfio_ap_set_new_guest_config(struct ap_matrix_mdev *matrix_mdev,
+ struct ap_matrix *m_new);
+
#endif /* _VFIO_AP_PRIVATE_H_ */
--
2.53.0
^ permalink raw reply related [flat|nested] 16+ messages in thread* [PATCH v7 10/15] s390/vfio-ap: File ops called to resume the vfio device migration
2026-08-07 22:18 [PATCH v7 00/15] s390/vfio-ap: Add live guest migration support Anthony Krowiak
` (8 preceding siblings ...)
2026-08-07 22:18 ` [PATCH v7 09/15] s390/vfio-ap: Add method to set a new guest AP configuration Anthony Krowiak
@ 2026-08-07 22:18 ` Anthony Krowiak
2026-08-07 22:18 ` [PATCH v7 11/15] s390/vfio-ap: Transition device migration state to STOP Anthony Krowiak
` (4 subsequent siblings)
14 siblings, 0 replies; 16+ messages in thread
From: Anthony Krowiak @ 2026-08-07 22:18 UTC (permalink / raw)
To: linux-s390, linux-kernel, kvm
Cc: jjherne, borntraeger, mjrosato, pasic, alex, kwankhede, fiuczy,
pbonzini, frankja, imbrenda, agordeev, hca, gor
Implements the 'write' callback function that was added to the
'file_operations' structure for the file stream created to restore the
state of the vfio-ap device on the destination system when the migration
state transitioned from STOP to RESUMING
The write callback retrieves the vfio device migration state saved to the
file stream created when the vfio device state was transitioned from
STOP to STOP_COPY. The saved state contains the source guest's AP
configuration information. This data is copied from the userspace buffer
passed to the 'write' callback and stored in the vfio_ap_config structure
used to set the state of the vfio-ap device on the destination host. If the
source guest's AP configuration is compatible with the AP configuration on
the destination host, it will be hot plugged into the destination guest.
In order for the source guest's and destination host's AP configurations
to be considered compatible:
* Each APQN in the source guest's AP configuration must also be in the
destination host's AP configuration
* Each matching APQN in the destination host's AP configuration must be
bound to the vfio_ap device driver
* Each matching APQN in the destination host's AP configuration must
reference a queue device with compatible hardware:
- The source and destination queues must have the same facilities
installed:
~ APSC facility
~ APQKM facility
~ AP4KC facility
- The source and destination queues must have the same mode:
~ Coprocessor-mode
~ Accelerator-mode
~ XCP-mode
- The source and destination queues must have the same APXA facility
setting
~ If the APXA facility is installed on source queue, it must also
be installed on the destination queue and vice versa
- The source and destination queues must have a compatible
classification setting. If the source queue has full native card
function, then the destination queue must also have full native
card function. If the source queue has stateless functions, then
the destination queue can have stateless functions or full native card
function because the latter includes the stateless functions.
- The binding and associated state for both the source and destination
queues must indicate that the queue is usable for all messages
(i.e., BS bits equal to 00).
- The AP type of the destination queue must be the same as or newer than
the source queue (backward compatibility)
Note: The get_hardware_info_for_queue function that was created in
a previous patch was modified to take a mediated device name rather
than an ap_matrix_mdev object because that is what is needed for
this patch so the function can be executed without holding the
matrix_dev->mdevs_lock.
Signed-off-by: Anthony Krowiak <akrowiak@linux.ibm.com>
---
drivers/s390/crypto/vfio_ap_migration.c | 1009 ++++++++++++++++++++++-
1 file changed, 1001 insertions(+), 8 deletions(-)
diff --git a/drivers/s390/crypto/vfio_ap_migration.c b/drivers/s390/crypto/vfio_ap_migration.c
index e2e7ae8515e5..4dd7373c3d9d 100644
--- a/drivers/s390/crypto/vfio_ap_migration.c
+++ b/drivers/s390/crypto/vfio_ap_migration.c
@@ -12,6 +12,61 @@
#define VFIO_AP_MIG_MAGIC 0x76666170U /* "vfap" */
#define VFIO_AP_MIG_VERSION 1U
+/*
+ * Masks the fields of the queue information returned from the PQAP(TAPQ)
+ * command. In order to migrate a guest, it's AP configuration must be
+ * compatible with AP configuration assigned to the target guest's mdev.
+ * This mask is used to verify that the queue information for each source and
+ * target queue is compatible.
+ *
+ * The following bits must match for the source device and the corresponding
+ * destination device:
+ * -------------------------------------------------------------------------
+ * S bit 0: APSC facility installed
+ * M bit 1: APQKM facility installed
+ * C bit 2: AP4KC facility installed
+ * Mode bits 3-5:
+ * D bit 3: CCA-mode facility
+ * A bit 4: accelerator-mode facility
+ * X bit 5: XCP-mode facility
+ * N bit 6: APXA facility installed
+ * SL bit 7: SLCF facility installed
+ *
+ * Either bit 8 or bit 9 will be set. If bit 8 is set for the source device,
+ * then it must also be set for the corresponding destination device:
+ * -------------------------------------------------------------------------
+ * Classification (functional capabilities) bits 8-16
+ * bit 8: Native card function
+ * bit 9: Only stateless functions
+ *
+ * The BS bits must be set to 0 for both the source and corresponding
+ * destination device:
+ * -------------------------------------------------------------------------
+ * BS bits 16-17:
+ *
+ * The AP type of the source device must be less than or equal to that of
+ * the corresponding destination device:
+ * -------------------------------------------------------------------------
+ * AP Type bits 32-40:
+ */
+#define QINFO_DATA_MASK 0xffffc000ff000000
+
+/*
+ * Masks the bit that indicates whether full native card function is available
+ * from the 8 bits specifying the functional capabilities of a queue
+ */
+#define CLASSIFICATION_NATIVE_FCN_MASK 0x80
+
+/* The maximum number of queues that can be installed in an s390 system */
+#define MAX_AP_QUEUES (AP_DEVICES * AP_DOMAINS)
+
+/*
+ * The size of the 'buf' array in struct vfio_ap_config_buffer. It needs to be
+ * large enough to store the first three fields (magic, version and num_queues)
+ * of a struct vfio_ap_config instance.
+ */
+#define VFIO_AP_CONFIG_BUF_SIZE (sizeof(u32) * 3)
+
/**
* struct vfio_ap_migration_file
*
@@ -29,6 +84,28 @@ struct vfio_ap_migration_file {
unsigned long config_sz;
};
+/**
+ * struct vfio_ap_config_buffer:
+ *
+ * During the RESUMING phase of migration, userspace may send AP configuration
+ * data in chunks. Until we know how many queues to which the source guest
+ * has access, it is not possible to allocate the appropriate amount of
+ * storage for a struct vfio_ap_config instance. The vfio_ap_config_buffer
+ * will accumulate the data until the 'num_queues' field of the vfio_ap_config
+ * object is sent.
+ *
+ * @filled: indicates whether the buffer is filled (true if it
+ * includes the 'num_queues' field) or not (false, i.e.,
+ * more data needs to be sent from userspace and read in).
+ * @bytes_read_in: the number of bytes that have been read into the buffer
+ * @buf: the buffer into which source data is read
+ */
+struct vfio_ap_config_buffer {
+ bool filled;
+ size_t bytes_read_in;
+ u8 buf[VFIO_AP_CONFIG_BUF_SIZE];
+};
+
/**
* struct vfio_ap_migration_data:
*
@@ -36,15 +113,25 @@ struct vfio_ap_migration_file {
* configuration of the guest being migrated.
*
* @mig_state: the current migration state
+ * @resuming_config_buf: buffer used for chunk writes of a struct vfio_ap_config
+ * object from userspace during the RESUMING phase of
+ * migration until the 'num_queues' field of the object has
+ * been written and read into the buffer.
* @resuming_mig_file: the object used to restore the state of the vfio-ap
* device on the destination host.
* @stop_copy_mig_file: the object used to store the AP configuration of the
* source guest for transfer to the destination host.
+ * @write_in_progress: true if a write() is currently in progress on the
+ * resuming migration file; used to reject concurrent
+ * writes, which are not supported on this streaming
+ * interface.
*/
struct vfio_ap_migration_data {
enum vfio_device_mig_state mig_state;
+ struct vfio_ap_config_buffer resuming_config_buf;
struct vfio_ap_migration_file resuming_mig_file;
struct vfio_ap_migration_file stop_copy_mig_file;
+ bool write_in_progress;
};
/**
@@ -125,9 +212,10 @@ vfio_ap_release_stop_copy_file(struct vfio_ap_migration_data *mig_data)
static void vfio_ap_release_resuming_file(struct vfio_ap_migration_data *mig_data)
{
- /* Stub to be implemented when the mig_data->resuming_mig_file.ap_config
- * object is allocated.
- */
+ kvfree(mig_data->resuming_mig_file.ap_config);
+ mig_data->resuming_mig_file.ap_config = NULL;
+ mig_data->resuming_mig_file.config_sz = 0;
+ mig_data->resuming_mig_file.filp = NULL;
}
static int vfio_ap_release_mig_file(struct inode *file_inode, struct file *filp)
@@ -221,7 +309,7 @@ static int get_hardware_info_for_queue(const char *mdev_name,
/* For all these RCs the tapq info should be available */
return 0;
case AP_RESPONSE_Q_NOT_AVAIL:
- pr_err_ratelimited("vfio_ap_mdev %s: Failed to get hwinfo for queue %02lx.%04lx: TAPQ rc=%d",
+ pr_err_ratelimited("vfio_ap_mdev %s: Failed to get hwinfo for queue %02lx.%04lx: TAPQ rc=%d\n",
mdev_name, AP_QID_CARD(apqn), AP_QID_QUEUE(apqn),
status.response_code);
return -ENODEV;
@@ -233,7 +321,7 @@ static int get_hardware_info_for_queue(const char *mdev_name,
if (status.async)
return 0;
- pr_err_ratelimited("vfio_ap_mdev %s:Failed to get hwinfo for queue %02lx.%04lx: TAPQ rc=%d",
+ pr_err_ratelimited("vfio_ap_mdev %s: Failed to get hwinfo for queue %02lx.%04lx: TAPQ rc=%d\n",
mdev_name, AP_QID_CARD(apqn), AP_QID_QUEUE(apqn),
status.response_code);
return -EIO;
@@ -288,7 +376,7 @@ static int vfio_ap_get_config(struct ap_matrix_mdev *matrix_mdev)
lockdep_assert_held(&matrix_dev->mdevs_lock);
- ap_config_size = vfio_ap_config_size(matrix_mdev, (int *)&num_queues);
+ ap_config_size = vfio_ap_config_size(matrix_mdev, &num_queues);
ap_configuration = kvzalloc(ap_config_size, GFP_KERNEL_ACCOUNT);
if (!ap_configuration)
@@ -451,11 +539,916 @@ static struct file *vfio_ap_open_file_stream(struct ap_matrix_mdev *matrix_mdev,
return filp;
}
+static int validate_resuming_write_parms(struct file *filp,
+ size_t len, loff_t *pos)
+{
+ struct vfio_ap_config_buffer resuming_config_buf;
+ struct vfio_ap_migration_file resuming_mig_file;
+ struct vfio_ap_migration_data *mig_data;
+ struct ap_matrix_mdev *matrix_mdev;
+ loff_t total_len;
+
+ lockdep_assert_held(&matrix_dev->mdevs_lock);
+
+ if (!len || *pos < 0)
+ return -EINVAL;
+
+ if (check_add_overflow((loff_t)len, *pos, &total_len))
+ return -ERANGE;
+
+ matrix_mdev = filp->private_data;
+ if (!matrix_mdev || !matrix_mdev->mig_data)
+ return -ENODEV;
+
+ mig_data = matrix_mdev->mig_data;
+ resuming_mig_file = mig_data->resuming_mig_file;
+ resuming_config_buf = mig_data->resuming_config_buf;
+
+ if (filp != resuming_mig_file.filp)
+ return -ENXIO;
+
+ /*
+ * Concurrent writes are not supported on this streaming interface.
+ * The write position, scratch buffer state, and ap_config pointer
+ * are all shared state that cannot be safely updated by more than
+ * one writer at a time.
+ */
+ if (mig_data->write_in_progress)
+ return -EBUSY;
+
+ /*
+ * If the vfio_ap_config_buffer is filled (i.e., the 'num_queues' field
+ * has been read in), then the vfio_ap_configuration should have been
+ * allocated and vice versa.
+ */
+ if ((resuming_config_buf.filled && !resuming_mig_file.ap_config) ||
+ (!resuming_config_buf.filled && resuming_mig_file.ap_config))
+ return -EFAULT;
+
+ /*
+ * If the vfio_ap_config object has been allocated, then the 'config_sz'
+ * field indicates the total size allocated. If the write operation
+ * will exceed the allocation, return an I/O error.
+ */
+ if (resuming_mig_file.ap_config) {
+ if (resuming_mig_file.ap_config->magic != VFIO_AP_MIG_MAGIC ||
+ resuming_mig_file.ap_config->version != VFIO_AP_MIG_VERSION)
+ return -EINVAL;
+
+ if (*pos + len > resuming_mig_file.config_sz)
+ return -EIO;
+ }
+
+ return 0;
+}
+
+static ssize_t calculate_ap_config_size(unsigned int num_queues)
+{
+ size_t qinfo_size;
+
+ if (num_queues > MAX_AP_QUEUES)
+ return -EINVAL;
+
+ qinfo_size = num_queues * sizeof(struct vfio_ap_queue_info);
+ return qinfo_size + sizeof(struct vfio_ap_config);
+}
+
+/**
+ * allocate_ap_config:
+ *
+ * Allocate storage for the source guest's AP configuration data sent from
+ * userspace.
+ *
+ * @ap_config_buf: Buffer containing the bytes comprising the 'magic', 'version'
+ * and 'num_queues' fields of a vfio_ap_config object.
+ * @ap_config: The location in which to store the pointer to the storage
+ * allocated for the AP configuration data.
+ *
+ * Returns: The number of bytes of storage allocated for the config data or
+ * an error:
+ *
+ * -EINVAL: if num_queues exceeds the maximum or @ap_config_buf is
+ * not filled (i.e., does not contain 'num_fields' value
+ * of a struct vfio_ap_config).
+ * -ENOMEM: the allocation of storage failed
+ */
+static ssize_t allocate_ap_config(struct vfio_ap_config_buffer *ap_config_buf,
+ struct vfio_ap_config **ap_config)
+{
+ struct vfio_ap_config tmp_ap_config;
+ ssize_t config_size;
+
+ lockdep_assert_held(&matrix_dev->mdevs_lock);
+
+ /*
+ * A vfio_ap_config object can be allocated only if the
+ * vfio_ap_config_buffer is filled, in which case we have the
+ * 'num_queues' field which is necessary to calculate the allocation
+ * size.
+ */
+ if (!ap_config_buf->filled)
+ return -EINVAL;
+ /*
+ * Copy the content of the vfio_ap_config_buffer so we can get the
+ * value of the 'num_queues' field
+ */
+ memcpy(&tmp_ap_config, ap_config_buf->buf, VFIO_AP_CONFIG_BUF_SIZE);
+
+ config_size = calculate_ap_config_size(tmp_ap_config.num_queues);
+ if (config_size < 0)
+ return config_size;
+
+ /*
+ * Use kvzalloc so that large configurations can fall back to vmalloc
+ * rather than failing a high-order contiguous physical allocation.
+ */
+ *ap_config = kvzalloc(config_size, GFP_KERNEL_ACCOUNT);
+ if (!*ap_config)
+ return -ENOMEM;
+
+ memcpy(*ap_config, ap_config_buf->buf, VFIO_AP_CONFIG_BUF_SIZE);
+
+ return config_size;
+}
+
+/**
+ * qdev_is_bound_to_vfio_ap:
+ *
+ * Query to determine whether a queue with the specified APQN is available on
+ * the host system and bound to the vfio_ap device driver.
+ *
+ * @apqn: The APQN of the queue device being queried
+ *
+ * Returns: True if there is a queue device with the specified @apqn installed
+ * in the system and is bound to the vfio_ap device driver; otherwise,
+ * returns false.
+ */
+static bool qdev_is_bound_to_vfio_ap(unsigned int apqn)
+{
+ struct ap_queue *queue;
+ bool is_bound = true;
+
+ queue = ap_get_qdev(apqn);
+ if (!queue)
+ return false;
+
+ if (queue->ap_dev.device.driver != &matrix_dev->vfio_ap_drv->driver)
+ is_bound = false;
+
+ put_device(&queue->ap_dev.device);
+
+ return is_bound;
+}
+
+/**
+ * queues_available:
+ *
+ * Query whether each queue from the source guest's AP configuration is
+ * available and bound to the vfio_ap device driver; if not, log an error
+ * message.
+ *
+ * @mdev_name: The mdev name to use in error messages
+ * @source_config: The object specifying the source guest's AP configuration
+ *
+ * Returns: true if each queue identified in @source_config is available and
+ * bound to the vfio_ap device driver; otherwise, returns false.
+ */
+static bool queues_available(const char *mdev_name,
+ struct vfio_ap_config *source_config)
+{
+ unsigned long apqn;
+ bool ret = true;
+
+ for (int i = 0; i < source_config->num_queues; i++) {
+ apqn = source_config->qinfo[i].apqn;
+
+ /*
+ * Find the queue device bound to the vfio_ap device driver. If it is
+ * not found, log an error and continue so users see all problems
+ * at once, not one-at-a-time through retries of the migration.
+ */
+ if (!qdev_is_bound_to_vfio_ap(apqn)) {
+ pr_err_ratelimited("vfio_ap_mdev %s: Queue %02lx.%04lx not available to vfio_ap driver on target host\n",
+ mdev_name, AP_QID_CARD(apqn), AP_QID_QUEUE(apqn));
+ ret = false;
+ }
+ }
+
+ return ret;
+}
+
+/**
+ * control_domains_available
+ *
+ * Query whether each control domain specified in the source guest's AP
+ * configuration is installed in the host system.
+ *
+ * @mdev_name: The name of the mdev to use when logging messages
+ * @source_config: The object specifying the source guest's AP config
+ *
+ * Returns: True if each control domain is installed; otherwise, logs an
+ * error message for each unavailable control domain and returns
+ * false.
+ */
+static bool control_domains_available(const char *mdev_name,
+ struct vfio_ap_config *source_config)
+{
+ unsigned long domain_num;
+ bool available = true;
+
+ for_each_set_bit_inv(domain_num, (unsigned long *)source_config->adm,
+ AP_DOMAINS) {
+ if (ap_test_config_ctrl_domain(domain_num))
+ continue;
+
+ pr_err_ratelimited("vfio_ap_mdev: %s: Control domain %04lx not available on the destination host\n",
+ mdev_name, domain_num);
+ available = false;
+ }
+
+ return available;
+}
+
+static void report_facilities_compatibility(const char *mdev_name,
+ unsigned long apqn,
+ struct ap_tapq_hwinfo *src_hwinfo,
+ struct ap_tapq_hwinfo *target_hwinfo)
+{
+ if (src_hwinfo->apsc != target_hwinfo->apsc) {
+ if (src_hwinfo->apsc) {
+ pr_err_ratelimited("vfio_ap_mdev %s: APSC facility installed in source queue %02lx.%04lx\n",
+ mdev_name, AP_QID_CARD(apqn), AP_QID_QUEUE(apqn));
+
+ pr_err_ratelimited("vfio_ap_mdev %s: APSC facility not installed in target queue %02lx.%04lx\n",
+ mdev_name, AP_QID_CARD(apqn), AP_QID_QUEUE(apqn));
+ } else {
+ pr_err_ratelimited("vfio_ap_mdev %s: APSC facility not installed in source queue %02lx.%04lx\n",
+ mdev_name, AP_QID_CARD(apqn), AP_QID_QUEUE(apqn));
+
+ pr_err_ratelimited("vfio_ap_mdev %s: APSC facility installed in target queue %02lx.%04lx\n",
+ mdev_name, AP_QID_CARD(apqn), AP_QID_QUEUE(apqn));
+ }
+ }
+
+ if (src_hwinfo->mex4k != target_hwinfo->mex4k) {
+ if (src_hwinfo->mex4k) {
+ pr_err_ratelimited("vfio_ap_mdev %s: mex4k facility installed in source queue %02lx.%04lx\n",
+ mdev_name, AP_QID_CARD(apqn), AP_QID_QUEUE(apqn));
+
+ pr_err_ratelimited("vfio_ap_mdev %s: mex4k facility not installed in target queue %02lx.%04lx\n",
+ mdev_name, AP_QID_CARD(apqn), AP_QID_QUEUE(apqn));
+ } else {
+ pr_err_ratelimited("vfio_ap_mdev %s: mex4k facility not installed in source queue %02lx.%04lx\n",
+ mdev_name, AP_QID_CARD(apqn), AP_QID_QUEUE(apqn));
+
+ pr_err_ratelimited("vfio_ap_mdev %s: mex4k facility installed in target queue %02lx.%04lx\n",
+ mdev_name, AP_QID_CARD(apqn), AP_QID_QUEUE(apqn));
+ }
+ }
+
+ if (src_hwinfo->crt4k != target_hwinfo->crt4k) {
+ if (src_hwinfo->crt4k) {
+ pr_err_ratelimited("vfio_ap_mdev %s: crt4k facility installed in source queue %02lx.%04lx\n",
+ mdev_name, AP_QID_CARD(apqn), AP_QID_QUEUE(apqn));
+
+ pr_err_ratelimited("vfio_ap_mdev %s: crt4k facility not installed in target queue %02lx.%04lx\n",
+ mdev_name, AP_QID_CARD(apqn), AP_QID_QUEUE(apqn));
+ } else {
+ pr_err_ratelimited("vfio_ap_mdev %s: crt4k facility not installed in source queue %02lx.%04lx\n",
+ mdev_name, AP_QID_CARD(apqn), AP_QID_QUEUE(apqn));
+
+ pr_err_ratelimited("vfio_ap_mdev %s: crt4k facility installed in target queue %02lx.%04lx\n",
+ mdev_name, AP_QID_CARD(apqn), AP_QID_QUEUE(apqn));
+ }
+ }
+}
+
+static void report_mode_compatibility(const char *mdev_name,
+ unsigned long apqn,
+ struct ap_tapq_hwinfo *src_hwinfo,
+ struct ap_tapq_hwinfo *target_hwinfo)
+{
+ if (src_hwinfo->cca != target_hwinfo->cca) {
+ if (src_hwinfo->cca) {
+ pr_err_ratelimited("vfio_ap_mdev %s: Coprocessor-mode facility installed in source queue %02lx.%04lx\n",
+ mdev_name, AP_QID_CARD(apqn), AP_QID_QUEUE(apqn));
+
+ pr_err_ratelimited("vfio_ap_mdev %s: Coprocessor-mode facility not installed in target queue %02lx.%04lx\n",
+ mdev_name, AP_QID_CARD(apqn), AP_QID_QUEUE(apqn));
+ } else {
+ pr_err_ratelimited("vfio_ap_mdev %s: Coprocessor-mode facility not installed in source queue %02lx.%04lx\n",
+ mdev_name, AP_QID_CARD(apqn), AP_QID_QUEUE(apqn));
+
+ pr_err_ratelimited("vfio_ap_mdev %s: Coprocessor-mode facility installed in target queue %02lx.%04lx\n",
+ mdev_name, AP_QID_CARD(apqn), AP_QID_QUEUE(apqn));
+ }
+ }
+
+ if (src_hwinfo->accel != target_hwinfo->accel) {
+ if (src_hwinfo->accel) {
+ pr_err_ratelimited("vfio_ap_mdev %s: Accelerator-mode facility installed in source queue %02lx.%04lx\n",
+ mdev_name, AP_QID_CARD(apqn), AP_QID_QUEUE(apqn));
+
+ pr_err_ratelimited("vfio_ap_mdev %s: Accelerator-mode facility not installed in target queue %02lx.%04lx\n",
+ mdev_name, AP_QID_CARD(apqn), AP_QID_QUEUE(apqn));
+ } else {
+ pr_err_ratelimited("vfio_ap_mdev %s: Accelerator-mode facility not installed in source queue %02lx.%04lx\n",
+ mdev_name, AP_QID_CARD(apqn), AP_QID_QUEUE(apqn));
+
+ pr_err_ratelimited("vfio_ap_mdev %s: Accelerator-mode facility installed in target queue %02lx.%04lx\n",
+ mdev_name, AP_QID_CARD(apqn), AP_QID_QUEUE(apqn));
+ }
+ }
+
+ if (src_hwinfo->ep11 != target_hwinfo->ep11) {
+ if (src_hwinfo->ep11) {
+ pr_err_ratelimited("vfio_ap_mdev %s: XCP-mode facility installed in source queue %02lx.%04lx\n",
+ mdev_name, AP_QID_CARD(apqn), AP_QID_QUEUE(apqn));
+
+ pr_err_ratelimited("vfio_ap_mdev %s: XCP-mode facility not installed in target queue %02lx.%04lx\n",
+ mdev_name, AP_QID_CARD(apqn), AP_QID_QUEUE(apqn));
+ } else {
+ pr_err_ratelimited("vfio_ap_mdev %s: XCP-mode facility not installed in source queue %02lx.%04lx\n",
+ mdev_name, AP_QID_CARD(apqn), AP_QID_QUEUE(apqn));
+
+ pr_err_ratelimited("vfio_ap_mdev %s: XCP-mode facility installed in target queue %02lx.%04lx\n",
+ mdev_name, AP_QID_CARD(apqn), AP_QID_QUEUE(apqn));
+ }
+ }
+}
+
+static void report_apxa_compatibility(const char *mdev_name,
+ unsigned long apqn,
+ struct ap_tapq_hwinfo *src_hwinfo,
+ struct ap_tapq_hwinfo *target_hwinfo)
+{
+ if (src_hwinfo->apxa != target_hwinfo->apxa) {
+ if (src_hwinfo->apxa) {
+ pr_err_ratelimited("vfio_ap_mdev %s: AP-extended-addressing (APXA) facility installed in source queue %02lx.%04lx\n",
+ mdev_name, AP_QID_CARD(apqn), AP_QID_QUEUE(apqn));
+
+ pr_err_ratelimited("vfio_ap_mdev %s: AP-extended-addressing (APXA) facility not installed in target queue %02lx.%04lx\n",
+ mdev_name, AP_QID_CARD(apqn), AP_QID_QUEUE(apqn));
+ } else {
+ pr_err_ratelimited("vfio_ap_mdev %s: AP-extended-addressing (APXA) facility not installed in source queue %02lx.%04lx\n",
+ mdev_name, AP_QID_CARD(apqn), AP_QID_QUEUE(apqn));
+
+ pr_err_ratelimited("vfio_ap_mdev %s: AP-extended-addressing (APXA) facility installed in target queue %02lx.%04lx\n",
+ mdev_name, AP_QID_CARD(apqn), AP_QID_QUEUE(apqn));
+ }
+ }
+}
+
+static void report_slcf_compatibility(const char *mdev_name,
+ unsigned long apqn,
+ struct ap_tapq_hwinfo *src_hwinfo,
+ struct ap_tapq_hwinfo *target_hwinfo)
+{
+ if (src_hwinfo->slcf != target_hwinfo->slcf) {
+ if (src_hwinfo->slcf) {
+ pr_err_ratelimited("vfio_ap_mdev %s: Stateless-command-filtering (SLCF) available in source queue %02lx.%04lx\n",
+ mdev_name, AP_QID_CARD(apqn), AP_QID_QUEUE(apqn));
+
+ pr_err_ratelimited("vfio_ap_mdev %s: Stateless-command-filtering (SLCF) not available in target queue %02lx.%04lx\n",
+ mdev_name, AP_QID_CARD(apqn), AP_QID_QUEUE(apqn));
+ } else {
+ pr_err_ratelimited("vfio_ap_mdev %s: Stateless-command-filtering (SLCF) not available in source queue %02lx.%04lx\n",
+ mdev_name, AP_QID_CARD(apqn), AP_QID_QUEUE(apqn));
+
+ pr_err_ratelimited("vfio_ap_mdev %s: Stateless-command-filtering (SLCF) available in target queue %02lx.%04lx\n",
+ mdev_name, AP_QID_CARD(apqn), AP_QID_QUEUE(apqn));
+ }
+ }
+}
+
+static void report_bs_compatibility(const char *mdev_name,
+ unsigned long apqn,
+ struct ap_tapq_hwinfo *src_hwinfo,
+ struct ap_tapq_hwinfo *target_hwinfo)
+{
+ /*
+ * The BS field on both the source and destination must be 0, so if one
+ * of them is not, then report an error.
+ */
+ if (src_hwinfo->bs || target_hwinfo->bs) {
+ pr_err_ratelimited("vfio_ap_mdev %s: Bind/associate state for source (%01x) and target (%01x) queue %02lx.%04lx must be 0\n",
+ mdev_name, src_hwinfo->bs, target_hwinfo->bs,
+ AP_QID_CARD(apqn), AP_QID_QUEUE(apqn));
+ }
+}
+
+static void report_aptype_compatibility(const char *mdev_name,
+ unsigned long apqn,
+ struct ap_tapq_hwinfo *src_hwinfo,
+ struct ap_tapq_hwinfo *target_hwinfo)
+{
+ if (src_hwinfo->at > target_hwinfo->at) {
+ pr_err_ratelimited("vfio_ap_mdev %s: AP type of source (%02x) not compatible with target (%02x)\n",
+ mdev_name, src_hwinfo->at, target_hwinfo->at);
+ }
+}
+
+static bool classes_compatible(struct ap_tapq_hwinfo *src_hwinfo,
+ struct ap_tapq_hwinfo *target_hwinfo)
+{
+ unsigned long src_native, target_native;
+
+ src_native = src_hwinfo->class & CLASSIFICATION_NATIVE_FCN_MASK;
+ target_native = target_hwinfo->class & CLASSIFICATION_NATIVE_FCN_MASK;
+
+ /*
+ * If the source queue has full native card function and the
+ * target queue has only stateless functions available, then
+ * there may be instructions that will not execute on the
+ * target queue. This shall be reported as an error.
+ *
+ * If the source queue has only stateless card functions and the
+ * target queue has full native card function available, then
+ * we are okay because the target queue can run all stateless card
+ * functions.
+ */
+ return (src_native != target_native) ? !src_native : true;
+}
+
+static void report_class_compatibility(const char *mdev_name,
+ unsigned long apqn,
+ struct ap_tapq_hwinfo *src_hwinfo,
+ struct ap_tapq_hwinfo *target_hwinfo)
+{
+ if (!classes_compatible(src_hwinfo, target_hwinfo)) {
+ pr_err_ratelimited("vfio_ap_mdev %s: Full native card function available on source queue %02lx.%04lx\n",
+ mdev_name, AP_QID_CARD(apqn), AP_QID_QUEUE(apqn));
+
+ pr_err_ratelimited("vfio_ap_mdev %s: Only stateless functions available on target queue %02lx.%04lx\n",
+ mdev_name, AP_QID_CARD(apqn), AP_QID_QUEUE(apqn));
+ }
+}
+
+/*
+ * Log a device error reporting that migration failed due to queue
+ * incompatibilities followed by a device error for each incompatible feature.
+ */
+static void report_qinfo_incompatibilities(const char *mdev_name,
+ unsigned long apqn,
+ struct ap_tapq_hwinfo *src_hwinfo,
+ struct ap_tapq_hwinfo *target_hwinfo)
+{
+ pr_err_ratelimited("vfio_ap_mdev %s: Migration failed: Source and target queue (%02lx.%04lx) not compatible\n",
+ mdev_name, AP_QID_CARD(apqn), AP_QID_QUEUE(apqn));
+
+ report_facilities_compatibility(mdev_name, apqn, src_hwinfo, target_hwinfo);
+ report_mode_compatibility(mdev_name, apqn, src_hwinfo, target_hwinfo);
+ report_apxa_compatibility(mdev_name, apqn, src_hwinfo, target_hwinfo);
+ report_slcf_compatibility(mdev_name, apqn, src_hwinfo, target_hwinfo);
+ report_aptype_compatibility(mdev_name, apqn, src_hwinfo, target_hwinfo);
+ report_bs_compatibility(mdev_name, apqn, src_hwinfo, target_hwinfo);
+ report_class_compatibility(mdev_name, apqn, src_hwinfo, target_hwinfo);
+}
+
+/**
+ * queue_hardware_info_is_compatible:
+ *
+ * Verify whether the hardware information for a source queue is compatible with
+ * the hardware info for the corresponding queue on this system.
+ *
+ * In order to be compatible, the hardware information for each queue must
+ * meet the following requirements:
+ *
+ * 1. The hardware facilities bits much match
+ * 2. The AP type of the source queue must be the same as or older than that
+ * of the target queue (target is backwards compatible)
+ * 3. The classification bits must indicate:
+ * - Both queues have full native card function or both have stateless
+ * functions available
+ * - If the classification bits don't match, then the only acceptable
+ * configuration is stateless functions for the source queue and
+ * full native function for the target queue
+ * 4. The BS bits for both queues must be 0 (Queue usable for all messages
+ * supported by the adapter)
+ *
+ * @mdev_name: The mdev name to use in error messages
+ * @apqn: The APQN for the queues
+ * @src_hwinfo: The hardware info for the source queue
+ * @target_hwinfo: The hardware info for the corresponding queue on this system
+ *
+ * Returns: true if the hardware info for the two queues is compatible;
+ * otherwise, returns false.
+ */
+static bool queue_hardware_info_is_compatible(const char *mdev_name,
+ unsigned long apqn,
+ struct ap_tapq_hwinfo *src_hwinfo,
+ struct ap_tapq_hwinfo *target_hwinfo)
+{
+ unsigned long src_bits, target_bits;
+
+ src_bits = src_hwinfo->value & QINFO_DATA_MASK;
+ target_bits = target_hwinfo->value & QINFO_DATA_MASK;
+
+ /* If all bits match the queues are compatible */
+ if (src_bits == target_bits &&
+ (src_hwinfo->bs == 0 && target_hwinfo->bs == 0))
+ return true;
+
+ if (src_hwinfo->apsc == target_hwinfo->apsc &&
+ src_hwinfo->mex4k == target_hwinfo->mex4k &&
+ src_hwinfo->crt4k == target_hwinfo->crt4k &&
+ src_hwinfo->cca == target_hwinfo->cca &&
+ src_hwinfo->accel == target_hwinfo->accel &&
+ src_hwinfo->ep11 == target_hwinfo->ep11 &&
+ src_hwinfo->slcf == target_hwinfo->slcf &&
+ src_hwinfo->apxa == target_hwinfo->apxa &&
+ src_hwinfo->at <= target_hwinfo->at &&
+ classes_compatible(src_hwinfo, target_hwinfo) &&
+ (src_hwinfo->bs == 0 && target_hwinfo->bs == 0))
+ return true;
+
+ report_qinfo_incompatibilities(mdev_name, apqn, src_hwinfo, target_hwinfo);
+
+ return false;
+}
+
+/**
+ * verify_ap_configs_are_compatible:
+ *
+ * Verifies that the queues in the source guest's AP configuration are
+ * compatible with the corresponding queues on this system.
+ *
+ * @mdev_name: The mdev name to use in error messages
+ * @source_config: The object specifying the source guest's AP configuration
+ *
+ * Returns: an error indicating either a failure to retrieve a queue's
+ * hardware information or one or more source queues are not
+ * compatible with the corresponding queue on this system; otherwise,
+ * returns zero to indicate compatibility.
+ */
+static int verify_ap_configs_are_compatible(const char *mdev_name,
+ struct vfio_ap_config *source_config)
+{
+ struct ap_tapq_hwinfo src_hwinfo, dest_hwinfo;
+ unsigned long apqn;
+ int ret = 0, rc;
+
+ for (int i = 0; i < source_config->num_queues; i++) {
+ apqn = source_config->qinfo[i].apqn;
+
+ /*
+ * If we can't get the hardware info for a particular queue, then let's
+ * capture the function return code and continue so we can log all
+ * errors to aid in debugging of migration.
+ */
+ rc = get_hardware_info_for_queue(mdev_name, &dest_hwinfo, apqn);
+ if (rc) {
+ ret = rc;
+ continue;
+ }
+
+ src_hwinfo.value = source_config->qinfo[i].data;
+
+ if (!queue_hardware_info_is_compatible(mdev_name, apqn,
+ &src_hwinfo,
+ &dest_hwinfo))
+ ret = -EINVAL;
+ }
+
+ return ret;
+}
+
+static int do_post_copy_validation(const char *mdev_name,
+ struct vfio_ap_config *source_config)
+{
+ if (!queues_available(mdev_name, source_config))
+ return -ENODEV;
+
+ if (!control_domains_available(mdev_name, source_config))
+ return -ENODEV;
+
+ return verify_ap_configs_are_compatible(mdev_name, source_config);
+}
+
+/**
+ * setup_ap_matrix_from_ap_config:
+ *
+ * Set the bits corresponding to the adapters, domains and control domains
+ * from the source guest's AP configuration into an ap_matrix object to be
+ * used to update the destination guest to run on this host.
+ *
+ * @ap_config: The source guest's AP configuration
+ * @guest_matrix: The object to be used to update the destination guest's
+ * AP configuration
+ */
+static void setup_ap_matrix_from_ap_config(struct vfio_ap_config *ap_config,
+ struct ap_matrix *guest_matrix)
+{
+ struct ap_config_info host_config_info = { 0 };
+ unsigned long apid, apqi, *guest_adm;
+ struct vfio_ap_queue_info qinfo;
+
+ ap_qci(&host_config_info);
+ /*
+ * Zero the bitmaps before calling vfio_ap_matrix_init(), which only
+ * sets the apm_max/aqm_max/adm_max scalar fields and leaves the bitmap
+ * arrays untouched. Without this, stack garbage in guest_matrix->apm,
+ * ->aqm, and ->adm would grant the destination guest access to
+ * arbitrary unassigned queues and control domains.
+ */
+ memset(guest_matrix->apm, 0, sizeof(guest_matrix->apm));
+ memset(guest_matrix->aqm, 0, sizeof(guest_matrix->aqm));
+ memset(guest_matrix->adm, 0, sizeof(guest_matrix->adm));
+ vfio_ap_matrix_init(&host_config_info, guest_matrix);
+
+ for (int i = 0; i < ap_config->num_queues; i++) {
+ qinfo = ap_config->qinfo[i];
+ apid = AP_QID_CARD(qinfo.apqn);
+ apqi = AP_QID_QUEUE(qinfo.apqn);
+
+ if (!test_bit_inv(apid, guest_matrix->apm))
+ set_bit_inv(apid, guest_matrix->apm);
+ if (!test_bit_inv(apqi, guest_matrix->aqm))
+ set_bit_inv(apqi, guest_matrix->aqm);
+ }
+
+ guest_adm = (unsigned long *)ap_config->adm;
+ for_each_set_bit_inv(apqi, guest_adm, AP_DOMAINS) {
+ if (!test_bit_inv(apqi, guest_matrix->adm))
+ set_bit_inv(apqi, guest_matrix->adm);
+ }
+}
+
+/**
+ * fill_resuming_config_buffer:
+ *
+ * Continue to fill the buffer that stores the first three fields (magic,
+ * version and num_queues) of a vfio_ap_config instance with data sent by
+ * userspace during the RESUMING phase of migration.
+ *
+ * @config_buf: reference to a 'struct vfio_ap_config_buffer' instance into which
+ * the data sent by userspace will be copied
+ * @buf: the buffer containing the data sent from userspace during the
+ * RESUMING phase of migration
+ * @len: reference to the length of data to be copied.
+ * @pos: reference to the starting position in @buf at which to store the
+ * data sent from userspace.
+ *
+ * Returns: 0 if the operation was successful; otherwise, returns an error.
+ */
+static int fill_resuming_config_buffer(struct vfio_ap_config_buffer *config_buf,
+ const char __user *buf, size_t len, loff_t pos)
+{
+ size_t copy_size, bytes_read_in;
+
+ /*
+ * Copy the data sent from userspace to @config_buf starting at @pos up
+ * to the maximum number of bytes that @config_buf can store.
+ */
+ copy_size = min(len, (size_t)VFIO_AP_CONFIG_BUF_SIZE - pos);
+ if (copy_from_user((char *)config_buf->buf + pos, buf, copy_size))
+ return -EFAULT;
+
+ bytes_read_in = copy_size + pos;
+ config_buf->bytes_read_in = bytes_read_in;
+ config_buf->filled = (bytes_read_in == (size_t)VFIO_AP_CONFIG_BUF_SIZE);
+
+ return 0;
+}
+
+static int do_post_copy_processing(struct ap_matrix_mdev *matrix_mdev,
+ struct vfio_ap_config *ap_config)
+{
+ const char *mdev_name = dev_name(matrix_mdev->vdev.dev);
+ struct ap_matrix guest_matrix;
+ int ret;
+
+ /*
+ * do_post_copy_validation() calls ap_tapq() which is a slow
+ * hardware instruction. Run it before acquiring the update
+ * locks to avoid holding guests_lock, kvm->lock, and
+ * mdevs_lock across the hardware calls.
+ */
+ ret = do_post_copy_validation(mdev_name, ap_config);
+ if (ret < 0)
+ return ret;
+
+ /*
+ * Let's set up the destination guest's AP configuration matrix from the
+ * source guest's AP configuration data sent from userspace.
+ */
+ setup_ap_matrix_from_ap_config(ap_config, &guest_matrix);
+
+ mutex_lock(&ap_attr_mutex);
+ get_update_locks_for_mdev(matrix_mdev);
+
+ /*
+ * Verify the device wasn't closed while mdevs_lock was dropped
+ * for the copy_from_user and do_post_copy_validation above.
+ * get_update_locks_for_mdev() reacquires mdevs_lock.
+ */
+ if (!matrix_mdev->mig_data) {
+ release_update_locks_for_mdev(matrix_mdev);
+ mutex_unlock(&ap_attr_mutex);
+ return -ENODEV;
+ }
+
+ /* Set the destination guest's AP configuration */
+ ret = vfio_ap_set_new_guest_config(matrix_mdev, &guest_matrix);
+
+ release_update_locks_for_mdev(matrix_mdev);
+ mutex_unlock(&ap_attr_mutex);
+
+ return ret;
+}
+
+/**
+ * set_new_ap_configuration:
+ *
+ * Sets the new AP configuration for the destination guest.
+ * @matrix_mdev: reference to the object used to maintain the guest's AP
+ * configuration
+ * @ap_config: reference to the vfio_ap_config instance containing the AP
+ * configuration data sent from userspace. If the reference to
+ * matrix_mdev->mig_data->resuming_mig_file.ap_config has not yet
+ * been set, then it will be set to @ap_config; otherwise, the
+ * content of @ap_config will be copied into
+ * matrix_mdev->mig_data->resuming_mig_file.ap_config.
+ * @cfg_sz:
+ */
+static int set_new_ap_configuration(struct ap_matrix_mdev *matrix_mdev,
+ struct vfio_ap_config *ap_config,
+ size_t cfg_sz)
+{
+ struct vfio_ap_config *cur_ap_config;
+
+ mutex_lock(&matrix_dev->mdevs_lock);
+ /*
+ * Re-read mig_data under the lock; the device could have been closed
+ * concurrently while the lock was dropped for copy_from_user().
+ */
+ if (!matrix_mdev->mig_data) {
+ mutex_unlock(&matrix_dev->mdevs_lock);
+ return -ENODEV;
+ }
+
+ cur_ap_config = matrix_mdev->mig_data->resuming_mig_file.ap_config;
+ if (cur_ap_config)
+ memcpy(cur_ap_config, ap_config, cfg_sz);
+ else
+ matrix_mdev->mig_data->resuming_mig_file.ap_config = ap_config;
+
+ matrix_mdev->mig_data->resuming_mig_file.config_sz = cfg_sz;
+ mutex_unlock(&matrix_dev->mdevs_lock);
+
+ return 0;
+}
+
static ssize_t vfio_ap_resuming_write(struct file *filp, const char __user *buf,
size_t len, loff_t *pos)
{
- /* TODO */
- return -EOPNOTSUPP;
+ struct vfio_ap_config_buffer *resuming_config_buf;
+ struct ap_matrix_mdev *matrix_mdev;
+ struct vfio_ap_config *ap_config;
+ bool new_allocation = false;
+ ssize_t ret, cfg_sz;
+ loff_t write_pos;
+ size_t write_len;
+
+ /*
+ * This file was opened with stream_open(), so pos should be NULL for
+ * sequential write() calls; a non-NULL pointer will be passed only
+ * for positional pwrite() calls in which case we return an error
+ * indicating broken pipe/illegal seek on a non-seekable file
+ */
+ if (pos)
+ return -ESPIPE;
+
+ mutex_lock(&matrix_dev->mdevs_lock);
+ pos = &filp->f_pos;
+
+ ret = validate_resuming_write_parms(filp, len, pos);
+ if (ret) {
+ mutex_unlock(&matrix_dev->mdevs_lock);
+ return ret;
+ }
+
+ matrix_mdev = filp->private_data;
+ matrix_mdev->mig_data->write_in_progress = true;
+ resuming_config_buf = &matrix_mdev->mig_data->resuming_config_buf;
+
+ /*
+ * If we have not yet filled the vfio_ap_config_buffer, then we need
+ * to continue filling it with data sent from userspace.
+ */
+ if (!resuming_config_buf->filled) {
+ ret = fill_resuming_config_buffer(resuming_config_buf, buf, len,
+ *pos);
+ if (ret) {
+ matrix_mdev->mig_data->write_in_progress = false;
+ mutex_unlock(&matrix_dev->mdevs_lock);
+ return ret;
+ }
+
+ /*
+ * If the vfio_ap_config_buffer is not yet filled, we don't
+ * yet have enough data to allocate the vfio_ap_config instance;
+ * otherwise, go ahead and allocate it.
+ */
+ if (!resuming_config_buf->filled) {
+ *pos += len;
+ matrix_mdev->mig_data->write_in_progress = false;
+ mutex_unlock(&matrix_dev->mdevs_lock);
+ return len;
+ }
+
+ ret = allocate_ap_config(resuming_config_buf, &ap_config);
+ if (ret < 0) {
+ matrix_mdev->mig_data->write_in_progress = false;
+ mutex_unlock(&matrix_dev->mdevs_lock);
+ return ret;
+ }
+
+ new_allocation = true;
+ cfg_sz = ret;
+ }
+
+ /*
+ * If this is not a new allocation of the vfio_ap_config object,
+ * then create a copy of it so we can continue filling it in via
+ * the copy_from_user() while the mdevs_lock is dropped.
+ */
+ if (!new_allocation) {
+ cfg_sz = matrix_mdev->mig_data->resuming_mig_file.config_sz;
+ ap_config = kvzalloc(cfg_sz, GFP_KERNEL_ACCOUNT);
+
+ if (!ap_config) {
+ matrix_mdev->mig_data->write_in_progress = false;
+ mutex_unlock(&matrix_dev->mdevs_lock);
+ return -ENOMEM;
+ }
+
+ memcpy(ap_config,
+ matrix_mdev->mig_data->resuming_mig_file.ap_config, cfg_sz);
+ }
+
+ /*
+ * If ap_config is a new allocation, then the contents of the
+ * 'magic', 'version' and 'num_queues' fields will already have
+ * been copied in; so the write_pos must be set to the location
+ * following the 'num_queues' field and the length to be written must be
+ * adjusted accordingly.
+ */
+ if (new_allocation) {
+ size_t nbytes_already_copied = VFIO_AP_CONFIG_BUF_SIZE - *pos;
+
+ write_pos = VFIO_AP_CONFIG_BUF_SIZE;
+ write_len = len - nbytes_already_copied;
+ buf += nbytes_already_copied;
+ } else {
+ write_pos = *pos;
+ write_len = len;
+ }
+
+ *pos += len;
+
+ mutex_unlock(&matrix_dev->mdevs_lock);
+
+ if (copy_from_user((char *)ap_config + write_pos, buf, write_len)) {
+ if (new_allocation)
+ kvfree(ap_config);
+ ret = -EFAULT;
+ goto out_clear_write_in_progress;
+ }
+
+ /* Check if we've completed writing the entire configuration */
+ if (write_pos + write_len == cfg_sz) {
+ ret = do_post_copy_processing(matrix_mdev, ap_config);
+
+ if (ret) {
+ kvfree(ap_config);
+ goto out_clear_write_in_progress;
+ }
+ }
+
+ ret = set_new_ap_configuration(matrix_mdev, ap_config, cfg_sz);
+ if (ret) {
+ kvfree(ap_config);
+ goto out_clear_write_in_progress;
+ }
+
+ /*
+ * If this is not a new allocation of vfio_ap_config, then the contents
+ * of ap_config would have been copied into the existing object, so we
+ * can free it so we don't leak the storage.
+ */
+ if (!new_allocation)
+ kvfree(ap_config);
+
+ ret = len;
+
+out_clear_write_in_progress:
+ mutex_lock(&matrix_dev->mdevs_lock);
+ if (matrix_mdev->mig_data)
+ matrix_mdev->mig_data->write_in_progress = false;
+ mutex_unlock(&matrix_dev->mdevs_lock);
+
+ return ret;
}
static const struct file_operations vfio_ap_resume_fops = {
--
2.53.0
^ permalink raw reply related [flat|nested] 16+ messages in thread* [PATCH v7 11/15] s390/vfio-ap: Transition device migration state to STOP
2026-08-07 22:18 [PATCH v7 00/15] s390/vfio-ap: Add live guest migration support Anthony Krowiak
` (9 preceding siblings ...)
2026-08-07 22:18 ` [PATCH v7 10/15] s390/vfio-ap: File ops called to resume the vfio device migration Anthony Krowiak
@ 2026-08-07 22:18 ` Anthony Krowiak
2026-08-07 22:18 ` [PATCH v7 12/15] s390/vfio-ap: Transition device migration state from STOP to RUNNING and vice versa Anthony Krowiak
` (3 subsequent siblings)
14 siblings, 0 replies; 16+ messages in thread
From: Anthony Krowiak @ 2026-08-07 22:18 UTC (permalink / raw)
To: linux-s390, linux-kernel, kvm
Cc: jjherne, borntraeger, mjrosato, pasic, alex, kwankhede, fiuczy,
pbonzini, frankja, imbrenda, agordeev, hca, gor
Typically at this point, interrupt processing for the device, DMA and other
changes to the device's external state must be prohibited. For VFIO AP,
there is no physical DMA device virtualized by the vfio-ap device . It
merely manages the guest's AP configuration that identifies the devices
passed through to the guest, but does not have access to any of them. Those
AP devices are passed through and controlled exclusively by the SIE program
used to start the guest. There only thing to do at this point is return
NULL to the caller since the file streams and associated data will get
cleaned up as a result of the VFIO migration framework releasing the files.
Signed-off-by: Anthony Krowiak <akrowiak@linux.ibm.com>
---
drivers/s390/crypto/vfio_ap_migration.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/drivers/s390/crypto/vfio_ap_migration.c b/drivers/s390/crypto/vfio_ap_migration.c
index 4dd7373c3d9d..30160e3ddded 100644
--- a/drivers/s390/crypto/vfio_ap_migration.c
+++ b/drivers/s390/crypto/vfio_ap_migration.c
@@ -1511,12 +1511,17 @@ vfio_ap_transition_to_state(struct ap_matrix_mdev *matrix_mdev,
return filp;
}
+ /*
+ * Terminates the data transfer session of the vfio-ap device state
+ * between the source and target hosts. Since the vfio-ap device does
+ * not virtualize a DMA device, there is no internal device state to
+ * incorporate into the vfio-ap device on the target.
+ */
if ((cur_state == VFIO_DEVICE_STATE_RESUMING &&
new_state == VFIO_DEVICE_STATE_STOP) ||
(cur_state == VFIO_DEVICE_STATE_STOP_COPY &&
new_state == VFIO_DEVICE_STATE_STOP)) {
- /* TODO */
- return ERR_PTR(-EOPNOTSUPP);
+ return NULL;
}
if ((cur_state == VFIO_DEVICE_STATE_STOP &&
--
2.53.0
^ permalink raw reply related [flat|nested] 16+ messages in thread* [PATCH v7 12/15] s390/vfio-ap: Transition device migration state from STOP to RUNNING and vice versa
2026-08-07 22:18 [PATCH v7 00/15] s390/vfio-ap: Add live guest migration support Anthony Krowiak
` (10 preceding siblings ...)
2026-08-07 22:18 ` [PATCH v7 11/15] s390/vfio-ap: Transition device migration state to STOP Anthony Krowiak
@ 2026-08-07 22:18 ` Anthony Krowiak
2026-08-07 22:18 ` [PATCH v7 13/15] s390/vfio-ap: Callback to get the size of data to be migrated during guest migration Anthony Krowiak
` (2 subsequent siblings)
14 siblings, 0 replies; 16+ messages in thread
From: Anthony Krowiak @ 2026-08-07 22:18 UTC (permalink / raw)
To: linux-s390, linux-kernel, kvm
Cc: jjherne, borntraeger, mjrosato, pasic, alex, kwankhede, fiuczy,
pbonzini, frankja, imbrenda, agordeev, hca, gor
The transition from STOP to RUNNING and vice versa indicates that
the vfio device is operating normally and migration is not
currently taking place. In this case, just set the new state.
Signed-off-by: Anthony Krowiak <akrowiak@linux.ibm.com>
---
drivers/s390/crypto/vfio_ap_migration.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/drivers/s390/crypto/vfio_ap_migration.c b/drivers/s390/crypto/vfio_ap_migration.c
index 30160e3ddded..24955f70e13e 100644
--- a/drivers/s390/crypto/vfio_ap_migration.c
+++ b/drivers/s390/crypto/vfio_ap_migration.c
@@ -1524,12 +1524,17 @@ vfio_ap_transition_to_state(struct ap_matrix_mdev *matrix_mdev,
return NULL;
}
+ /*
+ * These states indicate migration has either not been initiated or
+ * has completed and the vfio-ap device is operating normally. Since the
+ * vfio-ap device does not virtualize a DMA device, there is no internal
+ * device state to incorporate into the vfio-ap device on the target.
+ */
if ((cur_state == VFIO_DEVICE_STATE_STOP &&
new_state == VFIO_DEVICE_STATE_RUNNING) ||
(cur_state == VFIO_DEVICE_STATE_RUNNING &&
new_state == VFIO_DEVICE_STATE_STOP)) {
- /* TODO */
- return ERR_PTR(-EOPNOTSUPP);
+ return NULL;
}
/* vfio_mig_get_next_state() does not use arcs other than the above */
--
2.53.0
^ permalink raw reply related [flat|nested] 16+ messages in thread* [PATCH v7 13/15] s390/vfio-ap: Callback to get the size of data to be migrated during guest migration
2026-08-07 22:18 [PATCH v7 00/15] s390/vfio-ap: Add live guest migration support Anthony Krowiak
` (11 preceding siblings ...)
2026-08-07 22:18 ` [PATCH v7 12/15] s390/vfio-ap: Transition device migration state from STOP to RUNNING and vice versa Anthony Krowiak
@ 2026-08-07 22:18 ` Anthony Krowiak
2026-08-07 22:18 ` [PATCH v7 14/15] s390/vfio-ap: Add 'migratable' feature to sysfs 'features' attribute Anthony Krowiak
2026-08-07 22:18 ` [PATCH v7 15/15] s390/vfio-ap: Add live guest migration chapter to vfio-ap.rst Anthony Krowiak
14 siblings, 0 replies; 16+ messages in thread
From: Anthony Krowiak @ 2026-08-07 22:18 UTC (permalink / raw)
To: linux-s390, linux-kernel, kvm
Cc: jjherne, borntraeger, mjrosato, pasic, alex, kwankhede, fiuczy,
pbonzini, frankja, imbrenda, agordeev, hca, gor
Callback to get the estimated data length of the data that will be required
to complete reading of the vfio device's internal state. It's mandatory for
VFIO_DEVICE_FEATURE_MIGRATION migration support.
The function pointer for this callback is specified via the
'migration_get_data_size' field of the 'vfio_migration_ops' structure
which is stored with the VFIO device when the 'vfio_device'
structure representing the mediated device is initialized.
Signed-off-by: Anthony Krowiak <akrowiak@linux.ibm.com>
---
drivers/s390/crypto/vfio_ap_migration.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/drivers/s390/crypto/vfio_ap_migration.c b/drivers/s390/crypto/vfio_ap_migration.c
index 24955f70e13e..01933a62dab9 100644
--- a/drivers/s390/crypto/vfio_ap_migration.c
+++ b/drivers/s390/crypto/vfio_ap_migration.c
@@ -1636,7 +1636,15 @@ static int vfio_ap_get_state(struct vfio_device *vdev,
static int vfio_ap_get_data_size(struct vfio_device *vdev,
unsigned long *stop_copy_length)
{
- return -EOPNOTSUPP;
+ struct ap_matrix_mdev *matrix_mdev;
+ int num_queues;
+
+ mutex_lock(&matrix_dev->mdevs_lock);
+ matrix_mdev = container_of(vdev, struct ap_matrix_mdev, vdev);
+ *stop_copy_length = vfio_ap_config_size(matrix_mdev, &num_queues);
+ mutex_unlock(&matrix_dev->mdevs_lock);
+
+ return 0;
}
static const struct vfio_migration_ops vfio_ap_migration_ops = {
--
2.53.0
^ permalink raw reply related [flat|nested] 16+ messages in thread* [PATCH v7 14/15] s390/vfio-ap: Add 'migratable' feature to sysfs 'features' attribute
2026-08-07 22:18 [PATCH v7 00/15] s390/vfio-ap: Add live guest migration support Anthony Krowiak
` (12 preceding siblings ...)
2026-08-07 22:18 ` [PATCH v7 13/15] s390/vfio-ap: Callback to get the size of data to be migrated during guest migration Anthony Krowiak
@ 2026-08-07 22:18 ` Anthony Krowiak
2026-08-07 22:18 ` [PATCH v7 15/15] s390/vfio-ap: Add live guest migration chapter to vfio-ap.rst Anthony Krowiak
14 siblings, 0 replies; 16+ messages in thread
From: Anthony Krowiak @ 2026-08-07 22:18 UTC (permalink / raw)
To: linux-s390, linux-kernel, kvm
Cc: jjherne, borntraeger, mjrosato, pasic, alex, kwankhede, fiuczy,
pbonzini, frankja, imbrenda, agordeev, hca, gor
Add the 'migratable' feature to the features provided by the sysfs
/sys/devices/vfio_ap/matrix/feature attribute to indicate that migration
of vfio devices is supported. Since live guest migration is not supported
for SE guests, the 'migratable' feature will not be included when the
feature attribute is displayed.
Signed-off-by: Anthony Krowiak <akrowiak@linux.ibm.com>
---
drivers/s390/crypto/vfio_ap_drv.c | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)
diff --git a/drivers/s390/crypto/vfio_ap_drv.c b/drivers/s390/crypto/vfio_ap_drv.c
index 8e69ed286bb9..abfb34421d74 100644
--- a/drivers/s390/crypto/vfio_ap_drv.c
+++ b/drivers/s390/crypto/vfio_ap_drv.c
@@ -26,9 +26,21 @@ MODULE_LICENSE("GPL v2");
struct ap_matrix_dev *matrix_dev;
debug_info_t *vfio_ap_dbf_info;
+#define VFIO_AP_DRV_FEATURES "guest_matrix hotplug ap_config migratable"
+#define SE_GUEST_FEATURES "guest_matrix hotplug ap_config"
+
static ssize_t features_show(struct device *dev, struct device_attribute *attr, char *buf)
{
- return sysfs_emit(buf, "guest_matrix hotplug ap_config\n");
+ /*
+ * If the system running is an SE guest, it will support a different
+ * set of features; for example, it will not support live guest
+ * migration
+ */
+ if (ap_is_se_guest())
+ return sysfs_emit(buf, "%s\n", SE_GUEST_FEATURES);
+
+ /* Return all features supported by the vfio_ap device driver */
+ return sysfs_emit(buf, "%s\n", VFIO_AP_DRV_FEATURES);
}
static DEVICE_ATTR_RO(features);
--
2.53.0
^ permalink raw reply related [flat|nested] 16+ messages in thread* [PATCH v7 15/15] s390/vfio-ap: Add live guest migration chapter to vfio-ap.rst
2026-08-07 22:18 [PATCH v7 00/15] s390/vfio-ap: Add live guest migration support Anthony Krowiak
` (13 preceding siblings ...)
2026-08-07 22:18 ` [PATCH v7 14/15] s390/vfio-ap: Add 'migratable' feature to sysfs 'features' attribute Anthony Krowiak
@ 2026-08-07 22:18 ` Anthony Krowiak
14 siblings, 0 replies; 16+ messages in thread
From: Anthony Krowiak @ 2026-08-07 22:18 UTC (permalink / raw)
To: linux-s390, linux-kernel, kvm
Cc: jjherne, borntraeger, mjrosato, pasic, alex, kwankhede, fiuczy,
pbonzini, frankja, imbrenda, agordeev, hca, gor
Add a 'Live Guest Migration' chapter to the
Documentation/arch/s390/vfio-ap.rst document to describe the details for
initiating live guest migration for a guest to which AP adapters, domains
and control domains have been passed through.
Signed-off-by: Anthony Krowiak <akrowiak@linux.ibm.com>
---
Documentation/arch/s390/vfio-ap.rst | 616 +++++++++++++++++++++++-----
1 file changed, 517 insertions(+), 99 deletions(-)
diff --git a/Documentation/arch/s390/vfio-ap.rst b/Documentation/arch/s390/vfio-ap.rst
index ac0c07f76ddd..02d7cbe5e479 100644
--- a/Documentation/arch/s390/vfio-ap.rst
+++ b/Documentation/arch/s390/vfio-ap.rst
@@ -1012,7 +1012,7 @@ guest_matrix dyn ap_config
the following features are advertised:
----------------+---------------------------------------------------------------+
++--------------+---------------------------------------------------------------+
| Flag | Description |
+==============+===============================================================+
| guest_matrix | guest_matrix attribute exists. It reports the matrix of |
@@ -1021,105 +1021,523 @@ the following features are advertised:
+--------------+---------------------------------------------------------------+
| dyn | Indicates hot plug/unplug of AP adapters, domains and control |
| | domains for a guest to which the mdev is attached. |
-+------------+-----------------------------------------------------------------+
++--------------+---------------------------------------------------------------+
| ap_config | ap_config interface for one-shot modifications to mdev config |
+--------------+---------------------------------------------------------------+
+| migratable | Indicates that live guest migration is supported for guests |
+| | to which crypto devices are passed through |
++--------------+---------------------------------------------------------------+
-Limitations
-===========
-Live guest migration is not supported for guests using AP devices without
-intervention by a system administrator. Before a KVM guest can be migrated,
-the vfio_ap mediated device must be removed. Unfortunately, it can not be
-removed manually (i.e., echo 1 > /sys/devices/vfio_ap/matrix/$UUID/remove) while
-the mdev is in use by a KVM guest. If the guest is being emulated by QEMU,
-its mdev can be hot unplugged from the guest in one of two ways:
-
-1. If the KVM guest was started with libvirt, you can hot unplug the mdev via
- the following commands:
-
- virsh detach-device <guestname> <path-to-device-xml>
-
- For example, to hot unplug mdev 62177883-f1bb-47f0-914d-32a22e3a8804 from
- the guest named 'my-guest':
-
- virsh detach-device my-guest ~/config/my-guest-hostdev.xml
-
- The contents of my-guest-hostdev.xml:
-
-.. code-block:: xml
-
- <hostdev mode='subsystem' type='mdev' managed='no' model='vfio-ap'>
- <source>
- <address uuid='62177883-f1bb-47f0-914d-32a22e3a8804'/>
- </source>
- </hostdev>
-
-
- virsh qemu-monitor-command <guest-name> --hmp "device-del <device-id>"
-
- For example, to hot unplug the vfio_ap mediated device identified on the
- qemu command line with 'id=hostdev0' from the guest named 'my-guest':
-
-.. code-block:: sh
-
- virsh qemu-monitor-command my-guest --hmp "device_del hostdev0"
-
-2. A vfio_ap mediated device can be hot unplugged by attaching the qemu monitor
- to the guest and using the following qemu monitor command:
-
- (QEMU) device-del id=<device-id>
-
- For example, to hot unplug the vfio_ap mediated device that was specified
- on the qemu command line with 'id=hostdev0' when the guest was started:
-
- (QEMU) device-del id=hostdev0
-
-After live migration of the KVM guest completes, an AP configuration can be
-restored to the KVM guest by hot plugging a vfio_ap mediated device on the target
-system into the guest in one of two ways:
-
-1. If the KVM guest was started with libvirt, you can hot plug a matrix mediated
- device into the guest via the following virsh commands:
-
- virsh attach-device <guestname> <path-to-device-xml>
-
- For example, to hot plug mdev 62177883-f1bb-47f0-914d-32a22e3a8804 into
- the guest named 'my-guest':
-
- virsh attach-device my-guest ~/config/my-guest-hostdev.xml
-
- The contents of my-guest-hostdev.xml:
-
-.. code-block:: xml
-
- <hostdev mode='subsystem' type='mdev' managed='no' model='vfio-ap'>
- <source>
- <address uuid='62177883-f1bb-47f0-914d-32a22e3a8804'/>
- </source>
- </hostdev>
-
-
- virsh qemu-monitor-command <guest-name> --hmp \
- "device_add vfio-ap,sysfsdev=<path-to-mdev>,id=<device-id>"
-
- For example, to hot plug the vfio_ap mediated device
- 62177883-f1bb-47f0-914d-32a22e3a8804 into the guest named 'my-guest' with
- device-id hostdev0:
-
- virsh qemu-monitor-command my-guest --hmp \
- "device_add vfio-ap,\
- sysfsdev=/sys/devices/vfio_ap/matrix/62177883-f1bb-47f0-914d-32a22e3a8804,\
- id=hostdev0"
-
-2. A vfio_ap mediated device can be hot plugged by attaching the qemu monitor
- to the guest and using the following qemu monitor command:
-
- (qemu) device_add "vfio-ap,sysfsdev=<path-to-mdev>,id=<device-id>"
-
- For example, to plug the vfio_ap mediated device
- 62177883-f1bb-47f0-914d-32a22e3a8804 into the guest with the device-id
- hostdev0:
+Live Guest Migration
+====================
+The VFIO AP mediated device is not used to provide userspace with direct
+access to device memory as is the case with other devices that use the VFIO
+framework for device pass-through. Instead, it manages AP
+configuration metadata identifying the adapters, domains, and control
+domains to which a guest will be granted access. These AP resources are
+configured by assigning them to a vfio-ap mediated device via its sysfs
+assignment interfaces. When the guest is started, the vfio_ap device driver
+sets the guest's AP configuration from the metadata stored with the mediated
+device. The AP devices are not accessed directly through the vfio_ap driver,
+so the driver does not migrate the state of the AP devices themselves.
+Instead, it migrates the AP configuration metadata. The vfio_ap device
+driver on the destination host will then ensure that the AP configuration
+metadata migrated from the source host is compatible with the AP
+configuration available on the destination host and if
+so, will set the destination guest's AP configuration accordingly.
- (QEMU) device-add "vfio-ap,\
- sysfsdev=/sys/devices/vfio_ap/matrix/62177883-f1bb-47f0-914d-32a22e3a8804,\
- id=hostdev0"
+To be considered compatible, the AP configuration for the destination host must
+meet these requirements:
+
+* Each AP adapter, domain and control domain number assigned to the source
+ guest's AP configuration must be in the destination host's AP
+ configuration. This can be verified as follows:
+
+ * On the source host, display the AP configuration of the source guest
+ with the following two commands:
+
+ .. code-block:: bash
+
+ cat /sys/devices/vfio_ap/matrix/$UUID/guest_matrix
+ cat /sys/devices/vfio_ap/matrix/$UUID/control_domains
+
+ .. note::
+ Replace ``$UUID`` with the actual UUID of your mediated device.
+
+ The ``guest_matrix`` lists the APQNs of the queue devices assigned
+ to the mediated device; for example:
+
+ .. code-block:: bash
+
+ 00.0033
+ 00.003a
+
+ The ``control_domains`` lists the domain numbers of the control
+ domains; for example:
+
+ .. code-block:: bash
+
+ 0033
+ 003a
+
+ * Display the AP configuration of the destination host with the following
+ two commands:
+
+ .. code-block:: bash
+
+ lszcrypt -V
+ cat /sys/bus/ap/ap_control_domain_mask
+
+ .. note::
+ The ``lszcrypt -V`` command lists the AP cards (adapters) and queue
+ devices on the host system; for example:
+
+ .. code-block:: bash
+
+ =========== ===== ============ ==========
+ CARD.DOMAIN TYPE MODE DRIVER
+ =========== ===== ============ ==========
+ 00 CEX5C CCA-Coproc cex4card
+ 00.0033 CEX5C CCA-Coproc vfio_ap
+ 00.003a CEX5C CCA-Coproc vfio_ap
+ =========== ===== ============ ==========
+
+ Each bit in the ap_control_domain_mask corresponds to
+ domain numbers 0-255. If a bit is set to one, then
+ the control domain is available on the source host. For
+ example:
+
+ .. code-block:: bash
+
+ 0x0000000000001020000000000000000000000000000000000000000000000000
+
+ This mask indicates that AP control domains 51 (0x33) and 58 (0x3a) are
+ in the AP configuration of the host system.
+
+ * Verify the configurations:
+
+ * Each APQN in the guest's sysfs ``guest_matrix`` file must match an
+ APQN returned from the ``lszcrypt -V`` command on the destination host. It
+ is important to note the driver to which the queue is bound which
+ is displayed in the ``driver`` column. Queues not bound to the vfio_ap
+ driver are not available to the destination guest. Even if the APQNs are
+ available to the driver, that does not guarantee they can be used by the
+ guest being migrated; for example, migration will fail if any of these APQNs
+ are assigned to a mediated device other than the one being migrated.
+
+ * Each domain number from the source guest's sysfs
+ ``control_domains`` attribute must correspond to a bit set to one in
+ the destination host's ``ap_control_domain_mask``.
+
+
+* Each APQN assigned to the source guest and destination guest must
+ reference a queue device with compatible hardware capabilities:
+
+ +--------------+---------------------------------------------------------------+
+ | Hardware | Description |
+ | Capabilities | |
+ +==============+===============================================================+
+ | [1] | * AP special command facility (APSC) |
+ | Facilities | * AP 4096-bit ME PKU commands facility (AP4KM) |
+ | | * AP 4096-bit CRT PKU commands (AP4KC) |
+ +--------------+---------------------------------------------------------------+
+ | [1] Mode | * CCA-mode |
+ | | * Accelerator-mode |
+ | | * XCP-mode (EP11) |
+ +--------------+---------------------------------------------------------------+
+ | [1] AP | APXA installed |
+ | extended | |
+ | addressing | |
+ +--------------+---------------------------------------------------------------+
+ | [1] Command | Command filtering available |
+ | filtering | |
+ +--------------+---------------------------------------------------------------+
+ | [2] | * Full native card function |
+ | Functional | * Only stateless functions |
+ | capabilities | |
+ +--------------+---------------------------------------------------------------+
+ | [3] AP type | * 10 (0x0a): CEX4 |
+ | | * 11 (0x0b): CEX5 |
+ | | * 12 (0x0c) CEX6 |
+ | | * 13 (0x0d) CEX7 |
+ | | * 14 (0x0e) CEX8 |
+ +--------------+---------------------------------------------------------------+
+
+ +-----------------------------------------------------------------------------+
+ | Table Keys |
+ +=============================================================================+
+ | |
+ | [1] The hardware capability must be the same for both the source |
+ | and destination queue device. |
+ | |
+ | [2] The source and destination queues must either both have |
+ | full native card function or both have stateless functions. |
+ | If the functional capabilities don't match, then the source |
+ | queue can have stateless capabilities since full native card |
+ | function can handle stateless functions; otherwise, migration |
+ | will fail. |
+ | |
+ | [3] The AP type on the source and destination guests can |
+ | differ if the queue passed through to the target guest is a |
+ | newer model (backwards compatible) |
+ +-----------------------------------------------------------------------------+
+
+ * To verify the hardware capabilities are compatible:
+
+ * On both the source and destination hosts, display the hardware capabilities
+ for each AP adapter in the AP configuration for that host:
+
+ .. code-block:: bash
+
+ cat /sys/bus/ap/devices/card$APID/ap_functions
+
+ .. note::
+ The ``$APID`` is the two-character adapter number in hexadecimal format;
+ for example, ``card02`` or ``card1f``. The ``/sys/bus/ap/devices`` directory
+ also lists the APQNs of the queue devices installed in the respective
+ host system with the first two characters being the APID; for example:
+ ``02.0004`` or ``00.0033`` .
+
+ * Verify the hardware capabilities for each AP adapter device on the source
+ and destination host are compatible. The ``ap_functions`` attribute is a
+ bitmask. The bits in the mask read from left to right starting with bit 0.
+ Each bit that is set to one indicates the corresponding hardware capability
+ is installed:
+
+ * Bits 0-2 are the facilities bits. Each bit value must match for the AP
+ devices on the source and destination systems. The values indicate the
+ following:
+
+ * bit-0: APSC is installed
+ * bit-1: AP4KM is installed
+ * bit-2: AP4KC is installed
+
+ * Bits 3-5 specify the adapter Modes. Only one of these bits will be set to
+ one and must be the same for both the source and destination adapter
+ devices:
+
+ * bit-3: CCA-mode
+ * bit-4: Accelerator-mode
+ * bit-5: XCP-mode (EP11)
+
+ * Bit 6 specifies whether APXA is installed and must be the same for both
+ the source and destination adapter devices.
+
+ * Bit 7 specifies whether command filtering is installed
+ and must be the same for both the source and destination adapter devices.
+
+ * Bits 8-15 are the classification bits. There are only two relevant
+ bits and only one of them will be set to one. For the source and destination
+ adapter devices to be considered compatible:
+
+ * Bit 8 may be set to 1 on both hosts (full native card function)
+ * Bit 9 may be set to 1 on both hosts (only stateless functions available)
+ * Bit 9 may be set to 1 on the source host and bit 8 may be set to 1 on
+ the destination host
+
+ * Bits 16-17 are the binding state bits which must be 00
+
+ * To verify the AP types are compatible:
+
+ * On both the source and destination hosts, display the hardware type
+ for each AP adapter in the AP configuration for that host to ensure the
+ source and destination adapter types are the same, or the source type is
+ less than the destination type::
+
+ cat /sys/bus/ap/devices/card$APID/hwtype
+
+ .. note::
+ The ``$APID`` is the two-character adapter number in hexadecimal format;
+ for example, ``card02`` or ``card1f``.
+
+Setting up for live guest migration on the destination host
+-----------------------------------------------------------
+To set up a host as the destination for live guest migration, do the
+following:
+
+1. Create a mediated device
+~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Create a mediated device with the same name (UUID) as the mediated device
+used to supply the AP configuration to the source guest. For example, if
+the mediated device on the source guest is named
+62177883-f1bb-47f0-914d-32a22e3a8804:
+
+.. code-block:: bash
+
+ echo 62177883-f1bb-47f0-914d-32a22e3a8804 > \
+ /sys/devices/vfio_ap/matrix/mdev_supported_types/vfio_ap-passthrough/create
+
+2. Reserve adapters and domains for the vfio_ap device driver's use
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Reserve the same adapters, and domains passed through to the source guest
+for the vfio_ap device driver on the destination host by clearing the
+adapter numbers from the ``/sys/bus/ap/apmask`` and/or the domain numbers
+from the ``/sys/bus/ap/aqmask`` files.
+
+For example, suppose adapters 0, 20 (0x14) and 22 (0x16) as well as
+domains 51 (0x33) and 58 (0x3a) are passed through to the source guest. To
+ensure they can be passed through to the destination guest, they must be
+made available to the vfio_ap device driver on the destination host. To
+make them available, do one or both of the following on the destination host:
+
+.. code-block:: bash
+
+ echo -0,-0x14,-22 > /sys/bus/ap/apmask
+ echo -0,-0x33,-0x3a > /sys/bus/ap/aqmask
+
+.. note::
+
+ * It is not necessary to reserve both the adapters and domains.
+ Reserving an adapter implicitly allows the vfio_ap driver to assign
+ each of the domains available on the system along with the reserved
+ adapters to a guest's AP configuration and vice versa.
+
+ * The Cartesian product of the adapters and domains reserved for the
+ vfio_ap device driver identifies the APQNs of the AP queue devices to be
+ bound to the vfio_ap device driver. If an APQN does not reference a
+ queue device installed in the system at the time of live guest migration,
+ the migration will fail.
+
+ * It is not necessary to configure the destination mediated device with
+ adapters, domains and control domains because the source guest's AP
+ configuration will overlay the destination guest's during migration.
+
+ * To verify that the queue devices are reserved for the vfio_ap
+ device driver, issue the ``lszcrypt -V`` command and you should
+ see ``vfio_ap`` in the ``DRIVER`` column of the output.
+
+Live guest migration failures due to AP configuration errors
+------------------------------------------------------------
+This section describes the errors that may occur during live guest migration
+when the AP configuration of the source guest and destination host are not
+compatible and where to look for problem determination.
+
+The destination host is missing the mediated device
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+This error occurs when a mediated device with the same name (UUID) as the
+mediated device being migrated has not been created on the destination host.
+
+**Source host**
+
++--------------+----------------------------------------------------------------+
+| Log | Message |
++==============+================================================================+
+| Console log: | error: device not found: mediated device '$UUID' not |
+| | found |
++--------------+----------------------------------------------------------------+
+| QEMU log: | initiating migration |
+| | qemu-system-s390x: Sibling indicated error 1 |
++--------------+----------------------------------------------------------------+
+
+.. note::
+ $UUID is the UUID of the mediated device being migrated from the source host.
+
+
+One or more queues are not bound to the vfio_ap driver on the destination host
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+The queue devices passed through to the source guest are not installed in the
+destination host or are not bound to its vfio_ap device driver.
+
+**Source host**
+
++--------------+----------------------------------------------------------------+
+| Log | Message |
++==============+================================================================+
+| Console log: | error: operation failed: migration failed. Message from the |
+| | source host: operation failed: job 'migration out' failed: |
+| | Sibling indicated error 1. Message from the destination host: |
+| | operation failed: job 'migration in' failed: load of migration |
+| | failed: No such device: Failed to load vmstate version_id: 1, |
+| | ret: -19 |
++--------------+----------------------------------------------------------------+
+
+**Destination host**
+
++--------------+----------------------------------------------------------------+
+| Kernel log: | vfio_ap_mdev $UUID: Queue $APID.$APQI not available to |
+| | vfio_ap driver on target host |
++--------------+----------------------------------------------------------------+
+| QEMU log: | shutting down, reason=failed |
+| | qemu-system-s390x: terminating on signal $SIGNAL_NUM from |
+| | pid $PID $DAEMON |
++--------------+----------------------------------------------------------------+
+
+
+One or more control domains are not available on the destination host
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+The control domains passed through to the source guest are not installed on the
+destination host.
+
+**Source host**
+
++--------------+----------------------------------------------------------------+
+| Log | Message |
++==============+================================================================+
+| Console log: | error: operation failed: migration failed. Message from the |
+| | source host: operation failed: job 'migration out' failed: |
+| | Sibling indicated error 1. Message from the destination host: |
+| | operation failed: job 'migration in' failed: load of migration |
+| | failed: No such device: Failed to load vmstate version_id: 1, |
+| | ret: -19 |
++--------------+----------------------------------------------------------------+
+
+**Destination host**
+
++--------------+----------------------------------------------------------------+
+| Kernel log: | vfio_ap_mdev $UUID: Control domain $DOMAIN_NUM not available |
+| | on the destination host |
++--------------+----------------------------------------------------------------+
+| QEMU log: | shutting down, reason=failed |
+| | qemu-system-s390x: terminating on signal $SIGNAL_NUM from |
+| | pid $PID $DAEMON |
++--------------+----------------------------------------------------------------+
+
+
+.. note::
+ * $UUID is the UUID of the mediated device being migrated from the source host.
+ * $APID.$APQI is adapter number and queue index (domain number) comprising the
+ $APQN (for example, 00.0033) of the queue device that is not available.
+ * $SIGNAL_NUM is the signal number that caused the QEMU process to terminate.
+ * $PID is the process ID of the QEMU process on the destination host.
+ * $DAEMON is the name of the QEMU daemon process.
+ * This message will be logged for each queue for which this error is detected.
+
+Failure to get hardware information for a queue device on destination host
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+The vfio_ap device driver on the destination host will execute an AP instruction
+to get the hardware information for a queue device to perform queue compatibility
+checks. The instruction can fail for a number of reasons in which case the
+migration will be terminated.
+
+**Source host**
+
++--------------+----------------------------------------------------------------+
+| Log | Message |
++==============+================================================================+
+| Console log: | error: operation failed: migration failed. Message from the |
+| | source host: operation failed: job 'migration out' failed: |
+| | Sibling indicated error 1. Message from the destination host: |
+| | operation failed: job 'migration in' failed: load of migration |
+| | failed: failed to get hardware information for queue device |
+| | $APQN |
++--------------+----------------------------------------------------------------+
+
+**Destination host**
+
++--------------+----------------------------------------------------------------+
+| Log | Message |
++==============+================================================================+
+| Console log: | vfio_ap_mdev $UUID: migration failed: Failed to get hwinfo for |
+| | queue $APQN on target host: rc=$RESPONSE-CODE |
++--------------+----------------------------------------------------------------+
+| QEMU log: | shutting down, reason=failed |
+| | qemu-system-s390x: terminating on signal $SIGNAL-ID from pid |
+| | $PID $DAEMON |
++--------------+----------------------------------------------------------------+
+
+.. note::
+ * $UUID is the UUID of the mediated device being migrated from the source host.
+ * $APQN (for example, 00.0033) of the queue device that is not compatible.
+ * $RESPONSE_CODE is the response code from the AP instruction.
+ * $SIGNAL_NUM is the signal number of the signal that caused the QEMU process
+ to terminate.
+ * $PID is the process ID of the QEMU process on the destination host.
+ * $DAEMON is the name of the QEMU daemon process.
+ * This message will be logged for each queue for which this error is detected.
+
+The AP configurations of the source guest and destination host not compatible
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+The functional capabilities or facilities available on one or more of the queues
+passed through to the source guest are not compatible with the queue device with
+the same APQN on the destination system (see the Hardware Capabilities table above)
+
+**Source host**
+
++--------------+----------------------------------------------------------------+
+| Log | Message |
++==============+================================================================+
+| Console log: | error: operation failed: migration failed. Message from the |
+| | source host: operation failed: job 'migration out' failed: |
+| | Sibling indicated error 1. Message from the destination host: |
+| | operation failed: job 'migration in' failed: load of migration |
+| | failed: No such device: Failed to load vmstate version_id: 1, |
+| | ret: -19 |
++--------------+----------------------------------------------------------------+
+| Kernel log: | N/A |
++--------------+----------------------------------------------------------------+
+| QEMU log: | *initiating migration* |
+| | |
+| | *qemu-system-s390x: Sibling indicated error 1* |
++--------------+----------------------------------------------------------------+
+
+**Destination host**
+
++--------------+----------------------------------------------------------------+
+| Log | Message |
++==============+================================================================+
+| Console log: | N/A |
++--------------+----------------------------------------------------------------+
+| Kernel log: | *vfio_ap_mdev $UUID: Migration failed: Source and target |
+| | queue ($APQN) not compatible* |
+| | |
+| | The message above will be followed by one or more messages |
+| | enumerating the incompatible features; for example: |
+| | |
+| | ``vfio_ap_mdev $UUID: APSC facility installed in source queue |
+| | $APQN`` |
+| | ``vfio_ap_mdev $UUID: APSC facility not installed in target |
+| | queue $APQN`` |
+| | |
+| | ``AP type of source ($APTYPE1) not compatible with target |
+| | ($APTYPE2)`` ... |
++--------------+----------------------------------------------------------------+
+| QEMU log: | *initiating migration* |
+| | |
+| | *qemu-system-s390x: error while loading state section id ...* |
+| | |
+| | *shutting down, reason=failed* |
+| | |
+| | *terminating on signal $SIGNAL-ID from pid $PID $DAEMON* |
++--------------+----------------------------------------------------------------+
+
+.. note::
+ * $UUID is the UUID of the mediated device being migrated from the source host.
+ * $APQN (for example, 00.0033) of the queue device that is incompatible.
+ * $APTYPE1 is the type of the source queue device.
+ * $APTYPE2 is the type of the target queue device.
+ * $SIGNAL-ID is the signal number of the signal that caused the QEMU process
+ to terminate.
+ * $PROCESS-ID is the process ID of the QEMU process on the source host.
+ * $PID is the process ID of the QEMU process on the destination host.
+ * $DAEMON is the name of the QEMU daemon process.
+ * Each follow-on message logging the incompatibility will be logged for each
+ error detected for the specified queue device.
+
+AP Configuration Management
+---------------------------
+The AP configurations of the source guest and destination host must be kept
+in synchronization or live guest migration will likely fail due to potential
+incompatibilities introduced by such changes. In particular, changing adapter
+or domain reservations via the sysfs ``apmask`` or ``aqmask`` attributes on
+either the source or destination host without coordinating such changes between
+the two hosts -especially while a migration is taking place - can result in
+migration failures.
+
+Configuration stability is an orchestration-layer or system administrator
+responsibility, which is consistent with other VFIO device types. The vfio_ap
+device driver will validate source and destination configurations and provide
+clear diagnostics when incompatibilities are detected, enabling orchestration
+tools to implement appropriate policies; for example, blocking migration when
+such changes are to be made.
+
+Master Key administration
+--------------------------
+It is imperative that s390 Common Cryptographic Architecture (CCA) master key
+administration be performed on both the source and destination AP
+devices to synchronize the key values prior to allowing live guest
+migration. If the master keys do not match, then crypto applications that
+rely on secure keys wrapped by a CCA master key will fail when the guest on
+which they are running is migrated to the destination host. Again, this is
+an orchestration-layer or system administrator responsibility and migration must
+be blocked while master key administration is being performed.
--
2.53.0
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