[RFC 5/5] vfio/qat: Add vfio_pci driver for Intel QAT VF devices

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Add vfio pci driver for Intel QAT VF devices.

This driver uses vfio_pci_core to register to the VFIO subsystem. It
acts as a vfio agent and interacts with the QAT PF driver to implement
VF live migration.

Co-developed-by: Yahui Cao <yahui.cao@xxxxxxxxx>
Signed-off-by: Yahui Cao <yahui.cao@xxxxxxxxx>
Signed-off-by: Xin Zeng <xin.zeng@xxxxxxxxx>
---
 drivers/vfio/pci/Kconfig                 |   2 +
 drivers/vfio/pci/Makefile                |   1 +
 drivers/vfio/pci/qat/Kconfig             |  13 +
 drivers/vfio/pci/qat/Makefile            |   4 +
 drivers/vfio/pci/qat/qat_vfio_pci_main.c | 518 +++++++++++++++++++++++
 5 files changed, 538 insertions(+)
 create mode 100644 drivers/vfio/pci/qat/Kconfig
 create mode 100644 drivers/vfio/pci/qat/Makefile
 create mode 100644 drivers/vfio/pci/qat/qat_vfio_pci_main.c

diff --git a/drivers/vfio/pci/Kconfig b/drivers/vfio/pci/Kconfig
index f9d0c908e738..47c9773cf0c7 100644
--- a/drivers/vfio/pci/Kconfig
+++ b/drivers/vfio/pci/Kconfig
@@ -59,4 +59,6 @@ source "drivers/vfio/pci/mlx5/Kconfig"
 
 source "drivers/vfio/pci/hisilicon/Kconfig"
 
+source "drivers/vfio/pci/qat/Kconfig"
+
 endif
diff --git a/drivers/vfio/pci/Makefile b/drivers/vfio/pci/Makefile
index 24c524224da5..dcc6366df8fa 100644
--- a/drivers/vfio/pci/Makefile
+++ b/drivers/vfio/pci/Makefile
@@ -11,3 +11,4 @@ obj-$(CONFIG_VFIO_PCI) += vfio-pci.o
 obj-$(CONFIG_MLX5_VFIO_PCI)           += mlx5/
 
 obj-$(CONFIG_HISI_ACC_VFIO_PCI) += hisilicon/
+obj-$(CONFIG_QAT_VFIO_PCI) += qat/
diff --git a/drivers/vfio/pci/qat/Kconfig b/drivers/vfio/pci/qat/Kconfig
new file mode 100644
index 000000000000..38e5b4a0ca9c
--- /dev/null
+++ b/drivers/vfio/pci/qat/Kconfig
@@ -0,0 +1,13 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config QAT_VFIO_PCI
+	tristate "VFIO support for QAT VF PCI devices"
+	depends on X86
+	depends on VFIO_PCI_CORE
+	depends on CRYPTO_DEV_QAT
+	help
+	  This provides migration support for Intel(R) QAT Virtual Function
+	  using the VFIO framework.
+
+	  To compile this as a module, choose M here: the module
+	  will be called qat_vfio_pci. If you don't know what to do here,
+	  say N.
diff --git a/drivers/vfio/pci/qat/Makefile b/drivers/vfio/pci/qat/Makefile
new file mode 100644
index 000000000000..106791887b91
--- /dev/null
+++ b/drivers/vfio/pci/qat/Makefile
@@ -0,0 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
+obj-$(CONFIG_QAT_VFIO_PCI) += qat_vfio_pci.o
+qat_vfio_pci-y := qat_vfio_pci_main.o
+
diff --git a/drivers/vfio/pci/qat/qat_vfio_pci_main.c b/drivers/vfio/pci/qat/qat_vfio_pci_main.c
new file mode 100644
index 000000000000..af971fd05fd2
--- /dev/null
+++ b/drivers/vfio/pci/qat/qat_vfio_pci_main.c
@@ -0,0 +1,518 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright(c) 2023 Intel Corporation */
+#include <linux/anon_inodes.h>
+#include <linux/container_of.h>
+#include <linux/device.h>
+#include <linux/file.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/pci.h>
+#include <linux/sizes.h>
+#include <linux/types.h>
+#include <linux/uaccess.h>
+#include <linux/vfio_pci_core.h>
+#include <linux/qat/qat_vf_mig.h>
+
+struct qat_vf_mig_data {
+	u8 state[SZ_4K];
+};
+
+struct qat_vf_migration_file {
+	struct file *filp;
+	struct mutex lock; /* protect migration region context */
+	bool disabled;
+
+	size_t total_length;
+	struct qat_vf_mig_data mig_data;
+};
+
+struct qat_vf_core_device {
+	struct vfio_pci_core_device core_device;
+	struct pci_dev *parent;
+	int vf_id;
+
+	struct mutex state_mutex; /* protect migration state */
+	enum vfio_device_mig_state mig_state;
+	struct qat_vf_migration_file *resuming_migf;
+	struct qat_vf_migration_file *saving_migf;
+};
+
+static int qat_vf_init(struct qat_vf_core_device *qat_vdev)
+{
+	return qat_vfmig_init_device(qat_vdev->parent, qat_vdev->vf_id);
+}
+
+static void qat_vf_cleanup(struct qat_vf_core_device *qat_vdev)
+{
+	qat_vfmig_shutdown_device(qat_vdev->parent, qat_vdev->vf_id);
+}
+
+static int qat_vf_pci_open_device(struct vfio_device *core_vdev)
+{
+	int ret;
+	struct qat_vf_core_device *qat_vdev =
+		container_of(core_vdev, struct qat_vf_core_device,
+			     core_device.vdev);
+	struct vfio_pci_core_device *vdev = &qat_vdev->core_device;
+
+	ret = vfio_pci_core_enable(vdev);
+	if (ret)
+		return ret;
+
+	ret = qat_vf_init(qat_vdev);
+	if (ret) {
+		vfio_pci_core_disable(vdev);
+		return ret;
+	}
+	qat_vdev->mig_state = VFIO_DEVICE_STATE_RUNNING;
+
+	vfio_pci_core_finish_enable(vdev);
+
+	return 0;
+}
+
+static void qat_vf_disable_fd(struct qat_vf_migration_file *migf)
+{
+	mutex_lock(&migf->lock);
+	migf->disabled = true;
+	migf->total_length = 0;
+	migf->filp->f_pos = 0;
+	mutex_unlock(&migf->lock);
+}
+
+static void qat_vf_disable_fds(struct qat_vf_core_device *qat_vdev)
+{
+	if (qat_vdev->resuming_migf) {
+		qat_vf_disable_fd(qat_vdev->resuming_migf);
+		fput(qat_vdev->resuming_migf->filp);
+		qat_vdev->resuming_migf = NULL;
+	}
+
+	if (qat_vdev->saving_migf) {
+		qat_vf_disable_fd(qat_vdev->saving_migf);
+		fput(qat_vdev->saving_migf->filp);
+		qat_vdev->saving_migf = NULL;
+	}
+}
+
+static void qat_vf_pci_close_device(struct vfio_device *core_vdev)
+{
+	struct qat_vf_core_device *qat_vdev = container_of(core_vdev,
+			struct qat_vf_core_device, core_device.vdev);
+
+	qat_vf_cleanup(qat_vdev);
+	qat_vf_disable_fds(qat_vdev);
+	vfio_pci_core_close_device(core_vdev);
+}
+
+static int qat_vf_stop_device(struct qat_vf_core_device *qat_vdev)
+{
+	return qat_vfmig_suspend_device(qat_vdev->parent, qat_vdev->vf_id);
+}
+
+static ssize_t qat_vf_save_read(struct file *filp, char __user *buf,
+				size_t len, loff_t *pos)
+{
+	struct qat_vf_migration_file *migf = filp->private_data;
+	ssize_t done = 0;
+	loff_t *offs;
+	int ret;
+
+	if (pos)
+		return -ESPIPE;
+	offs = &filp->f_pos;
+
+	mutex_lock(&migf->lock);
+	if (*offs > migf->total_length || *offs < 0) {
+		done = -EINVAL;
+		goto out_unlock;
+	}
+
+	if (migf->disabled) {
+		done = -ENODEV;
+		goto out_unlock;
+	}
+
+	len = min_t(size_t, migf->total_length - *offs, len);
+	if (len) {
+		ret = copy_to_user(buf, &migf->mig_data + *offs, len);
+		if (ret) {
+			done = -EFAULT;
+			goto out_unlock;
+		}
+		*offs += len;
+		done = len;
+	}
+
+out_unlock:
+	mutex_unlock(&migf->lock);
+	return done;
+}
+
+static int qat_vf_release_file(struct inode *inode, struct file *filp)
+{
+	struct qat_vf_migration_file *migf = filp->private_data;
+
+	qat_vf_disable_fd(migf);
+	mutex_destroy(&migf->lock);
+	kfree(migf);
+
+	return 0;
+}
+
+static const struct file_operations qat_vf_save_fops = {
+	.owner = THIS_MODULE,
+	.read = qat_vf_save_read,
+	.release = qat_vf_release_file,
+	.llseek = no_llseek,
+};
+
+static int qat_vf_save_state(struct qat_vf_core_device *qat_vdev,
+			     struct qat_vf_migration_file *migf)
+{
+	struct qat_vf_mig_data *mig_data = &migf->mig_data;
+	int ret;
+
+	ret = qat_vfmig_save_state(qat_vdev->parent, qat_vdev->vf_id,
+				   mig_data->state,
+				   sizeof(mig_data->state));
+	if (ret)
+		return ret;
+
+	migf->total_length = sizeof(struct qat_vf_mig_data);
+
+	return 0;
+}
+
+static struct qat_vf_migration_file *
+qat_vf_save_device_data(struct qat_vf_core_device *qat_vdev)
+{
+	struct qat_vf_migration_file *migf;
+	int ret;
+
+	migf = kzalloc(sizeof(*migf), GFP_KERNEL);
+	if (!migf)
+		return ERR_PTR(-ENOMEM);
+
+	migf->filp = anon_inode_getfile("qat_vf_mig", &qat_vf_save_fops,
+					migf, O_RDONLY);
+	ret = PTR_ERR_OR_ZERO(migf->filp);
+	if (ret) {
+		kfree(migf);
+		return ERR_PTR(ret);
+	}
+
+	stream_open(migf->filp->f_inode, migf->filp);
+	mutex_init(&migf->lock);
+
+	ret = qat_vf_save_state(qat_vdev, migf);
+	if (ret) {
+		fput(migf->filp);
+		kfree(migf);
+		return ERR_PTR(ret);
+	}
+
+	return migf;
+}
+
+static ssize_t qat_vf_resume_write(struct file *filp, const char __user *buf,
+				   size_t len, loff_t *pos)
+{
+	struct qat_vf_migration_file *migf = filp->private_data;
+	loff_t requested_length;
+	ssize_t done = 0;
+	loff_t *offs;
+	int ret;
+
+	if (pos)
+		return -ESPIPE;
+	offs = &filp->f_pos;
+
+	if (*offs < 0 ||
+	    check_add_overflow((loff_t)len, *offs, &requested_length))
+		return -EOVERFLOW;
+
+	if (requested_length > sizeof(struct qat_vf_mig_data))
+		return -ENOMEM;
+
+	mutex_lock(&migf->lock);
+	if (migf->disabled) {
+		done = -ENODEV;
+		goto out_unlock;
+	}
+
+	ret = copy_from_user(&migf->mig_data + *offs, buf, len);
+	if (ret) {
+		done = -EFAULT;
+		goto out_unlock;
+	}
+	*offs += len;
+	done = len;
+	migf->total_length += len;
+
+out_unlock:
+	mutex_unlock(&migf->lock);
+	return done;
+}
+
+static const struct file_operations qat_vf_resume_fops = {
+	.owner = THIS_MODULE,
+	.write = qat_vf_resume_write,
+	.release = qat_vf_release_file,
+	.llseek = no_llseek,
+};
+
+static struct qat_vf_migration_file *
+qat_vf_resume_device_data(struct qat_vf_core_device *qat_vdev)
+{
+	struct qat_vf_migration_file *migf;
+	int ret;
+
+	migf = kzalloc(sizeof(*migf), GFP_KERNEL);
+	if (!migf)
+		return ERR_PTR(-ENOMEM);
+
+	migf->filp = anon_inode_getfile("qat_vf_mig", &qat_vf_resume_fops,
+					migf, O_WRONLY);
+	ret = PTR_ERR_OR_ZERO(migf->filp);
+	if (ret) {
+		kfree(migf);
+		return ERR_PTR(ret);
+	}
+	stream_open(migf->filp->f_inode, migf->filp);
+	mutex_init(&migf->lock);
+
+	return migf;
+}
+
+static int qat_vf_load_state(struct qat_vf_core_device *qat_vdev,
+			     struct qat_vf_migration_file *migf)
+{
+	struct qat_vf_mig_data *mig_data = &migf->mig_data;
+
+	return qat_vfmig_load_state(qat_vdev->parent, qat_vdev->vf_id,
+				    mig_data->state,
+				    sizeof(mig_data->state));
+}
+
+static int qat_vf_load_device_data(struct qat_vf_core_device *qat_vdev)
+{
+	return qat_vf_load_state(qat_vdev, qat_vdev->resuming_migf);
+}
+
+static int qat_vf_start_device(struct qat_vf_core_device *qat_vdev)
+{
+	return qat_vfmig_resume_device(qat_vdev->parent, qat_vdev->vf_id);
+}
+
+static struct file *qat_vf_pci_step_device_state(struct qat_vf_core_device *qat_vdev, u32 new)
+{
+	u32 cur = qat_vdev->mig_state;
+	int ret;
+
+	if (cur == VFIO_DEVICE_STATE_RUNNING  && new == VFIO_DEVICE_STATE_STOP) {
+		ret = qat_vf_stop_device(qat_vdev);
+		if (ret)
+			return ERR_PTR(ret);
+		return NULL;
+	}
+
+	if (cur == VFIO_DEVICE_STATE_STOP && new == VFIO_DEVICE_STATE_STOP_COPY) {
+		struct qat_vf_migration_file *migf;
+
+		migf = qat_vf_save_device_data(qat_vdev);
+		if (IS_ERR(migf))
+			return ERR_CAST(migf);
+		get_file(migf->filp);
+		qat_vdev->saving_migf = migf;
+		return migf->filp;
+	}
+
+	if (cur == VFIO_DEVICE_STATE_STOP_COPY && new == VFIO_DEVICE_STATE_STOP) {
+		qat_vf_disable_fds(qat_vdev);
+		return NULL;
+	}
+
+	if (cur == VFIO_DEVICE_STATE_STOP && new == VFIO_DEVICE_STATE_RESUMING) {
+		struct qat_vf_migration_file *migf;
+
+		migf = qat_vf_resume_device_data(qat_vdev);
+		if (IS_ERR(migf))
+			return ERR_CAST(migf);
+		get_file(migf->filp);
+		qat_vdev->resuming_migf = migf;
+		return migf->filp;
+	}
+
+	if (cur == VFIO_DEVICE_STATE_RESUMING && new == VFIO_DEVICE_STATE_STOP) {
+		ret = qat_vf_load_device_data(qat_vdev);
+		if (ret)
+			return ERR_PTR(ret);
+
+		qat_vf_disable_fds(qat_vdev);
+		return NULL;
+	}
+
+	if (cur == VFIO_DEVICE_STATE_STOP && new == VFIO_DEVICE_STATE_RUNNING) {
+		qat_vf_start_device(qat_vdev);
+		return NULL;
+	}
+
+	/* vfio_mig_get_next_state() does not use arcs other than the above */
+	WARN_ON(true);
+	return ERR_PTR(-EINVAL);
+}
+
+static struct file *qat_vf_pci_set_device_state(struct vfio_device *vdev,
+						enum vfio_device_mig_state new_state)
+{
+	struct qat_vf_core_device *qat_vdev = container_of(vdev,
+			struct qat_vf_core_device, core_device.vdev);
+	enum vfio_device_mig_state next_state;
+	struct file *res = NULL;
+	int ret;
+
+	mutex_lock(&qat_vdev->state_mutex);
+	while (new_state != qat_vdev->mig_state) {
+		ret = vfio_mig_get_next_state(vdev, qat_vdev->mig_state,
+					      new_state, &next_state);
+		if (ret) {
+			res = ERR_PTR(-EINVAL);
+			break;
+		}
+
+		res = qat_vf_pci_step_device_state(qat_vdev, next_state);
+		if (IS_ERR(res))
+			break;
+		qat_vdev->mig_state = next_state;
+		if (WARN_ON(res && new_state != qat_vdev->mig_state)) {
+			fput(res);
+			res = ERR_PTR(-EINVAL);
+			break;
+		}
+	}
+	mutex_unlock(&qat_vdev->state_mutex);
+
+	return res;
+}
+
+static int qat_vf_pci_get_device_state(struct vfio_device *vdev,
+				       enum vfio_device_mig_state *curr_state)
+{
+	struct qat_vf_core_device *qat_vdev = container_of(vdev,
+			struct qat_vf_core_device, core_device.vdev);
+
+	mutex_lock(&qat_vdev->state_mutex);
+	*curr_state = qat_vdev->mig_state;
+	mutex_unlock(&qat_vdev->state_mutex);
+
+	return 0;
+}
+
+static int qat_vf_pci_get_data_size(struct vfio_device *vdev,
+				    unsigned long *stop_copy_length)
+{
+	*stop_copy_length = sizeof(struct qat_vf_mig_data);
+	return 0;
+}
+
+static const struct vfio_migration_ops qat_vf_pci_mig_ops = {
+	.migration_set_state = qat_vf_pci_set_device_state,
+	.migration_get_state = qat_vf_pci_get_device_state,
+	.migration_get_data_size = qat_vf_pci_get_data_size,
+};
+
+static int qat_vf_pci_init_dev(struct vfio_device *core_vdev)
+{
+	struct qat_vf_core_device *qat_vdev = container_of(core_vdev,
+			struct qat_vf_core_device, core_device.vdev);
+
+	mutex_init(&qat_vdev->state_mutex);
+
+	core_vdev->migration_flags = VFIO_MIGRATION_STOP_COPY;
+	core_vdev->mig_ops = &qat_vf_pci_mig_ops;
+
+	return vfio_pci_core_init_dev(core_vdev);
+}
+
+static const struct vfio_device_ops qat_vf_pci_ops = {
+	.name = "qat-vf-vfio-pci",
+	.init = qat_vf_pci_init_dev,
+	.release = vfio_pci_core_release_dev,
+	.open_device = qat_vf_pci_open_device,
+	.close_device = qat_vf_pci_close_device,
+	.ioctl = vfio_pci_core_ioctl,
+	.read = vfio_pci_core_read,
+	.write = vfio_pci_core_write,
+	.mmap = vfio_pci_core_mmap,
+	.request = vfio_pci_core_request,
+	.match = vfio_pci_core_match,
+	.bind_iommufd = vfio_iommufd_physical_bind,
+	.unbind_iommufd = vfio_iommufd_physical_unbind,
+	.attach_ioas = vfio_iommufd_physical_attach_ioas,
+};
+
+static int
+qat_vf_vfio_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
+{
+	struct device *dev = &pdev->dev;
+	struct qat_vf_core_device *qat_vdev;
+	int ret;
+
+	qat_vdev = vfio_alloc_device(qat_vf_core_device, core_device.vdev, dev, &qat_vf_pci_ops);
+	if (IS_ERR(qat_vdev))
+		return PTR_ERR(qat_vdev);
+
+	qat_vdev->vf_id = pci_iov_vf_id(pdev);
+	qat_vdev->parent = pdev->physfn;
+	if (!qat_vdev->parent || qat_vdev->vf_id < 0)
+		return -EINVAL;
+
+	pci_set_drvdata(pdev, &qat_vdev->core_device);
+	ret = vfio_pci_core_register_device(&qat_vdev->core_device);
+	if (ret)
+		goto out_put_device;
+
+	return 0;
+
+out_put_device:
+	vfio_put_device(&qat_vdev->core_device.vdev);
+	return ret;
+}
+
+static struct qat_vf_core_device *qat_vf_drvdata(struct pci_dev *pdev)
+{
+	struct vfio_pci_core_device *core_device = pci_get_drvdata(pdev);
+
+	return container_of(core_device, struct qat_vf_core_device, core_device);
+}
+
+static void qat_vf_vfio_pci_remove(struct pci_dev *pdev)
+{
+	struct qat_vf_core_device *qat_vdev = qat_vf_drvdata(pdev);
+
+	vfio_pci_core_unregister_device(&qat_vdev->core_device);
+	vfio_put_device(&qat_vdev->core_device.vdev);
+}
+
+static const struct pci_device_id qat_vf_vfio_pci_table[] = {
+	/* Intel QAT GEN4 4xxx VF device */
+	{ PCI_DRIVER_OVERRIDE_DEVICE_VFIO(PCI_VENDOR_ID_INTEL, 0x4941) },
+	{}
+};
+MODULE_DEVICE_TABLE(pci, qat_vf_vfio_pci_table);
+
+static struct pci_driver qat_vf_vfio_pci_driver = {
+	.name = "qat_vfio_pci",
+	.id_table = qat_vf_vfio_pci_table,
+	.probe = qat_vf_vfio_pci_probe,
+	.remove = qat_vf_vfio_pci_remove,
+	.driver_managed_dma = true,
+};
+module_pci_driver(qat_vf_vfio_pci_driver)
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Intel Corporation");
+MODULE_DESCRIPTION("QAT VFIO PCI - VFIO PCI driver with live migration support for Intel(R) QAT device family");
-- 
2.18.2




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