[RFC PATCH vfio 1/7] vfio/pds: Initial support for pds_vfio VFIO driver

[Brett Creeley <brett.creeley@amd.com>]

This is the initial framework for the new pds_vfio device driver. This
does the very basics of registering the PCI device 1dd8:1006 and
configuring as a VFIO PCI device.

With this change, the VF device can be bound to the pds_vfio driver on
the host and presented to the VM as an NVMe VF.

Signed-off-by: Brett Creeley <brett.creeley@amd.com>
Signed-off-by: Shannon Nelson <shannon.nelson@amd.com>
---
 drivers/vfio/pci/pds/Makefile   |   8 +++
 drivers/vfio/pci/pds/pci_drv.c  | 100 ++++++++++++++++++++++++++++++++
 drivers/vfio/pci/pds/vfio_dev.c |  74 +++++++++++++++++++++++
 drivers/vfio/pci/pds/vfio_dev.h |  23 ++++++++
 include/linux/pds/pds_core_if.h |   1 +
 5 files changed, 206 insertions(+)
 create mode 100644 drivers/vfio/pci/pds/Makefile
 create mode 100644 drivers/vfio/pci/pds/pci_drv.c
 create mode 100644 drivers/vfio/pci/pds/vfio_dev.c
 create mode 100644 drivers/vfio/pci/pds/vfio_dev.h

diff --git a/drivers/vfio/pci/pds/Makefile b/drivers/vfio/pci/pds/Makefile
new file mode 100644
index 000000000000..cd012648a655
--- /dev/null
+++ b/drivers/vfio/pci/pds/Makefile
@@ -0,0 +1,8 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_PDS_VFIO_PCI) += pds_vfio.o
+
+pds_vfio-y := \
+	pci_drv.o	\
+	vfio_dev.o
+
+
diff --git a/drivers/vfio/pci/pds/pci_drv.c b/drivers/vfio/pci/pds/pci_drv.c
new file mode 100644
index 000000000000..9a601194201d
--- /dev/null
+++ b/drivers/vfio/pci/pds/pci_drv.c
@@ -0,0 +1,100 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright(c) 2022 Pensando Systems, Inc */
+
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/types.h>
+#include <linux/vfio.h>
+
+#include <linux/pds/pds_core_if.h>
+
+#include "vfio_dev.h"
+
+#define PDS_VFIO_DRV_NAME		"pds_vfio"
+#define PDS_VFIO_DRV_DESCRIPTION	"Pensando VFIO Device Driver"
+#define PCI_VENDOR_ID_PENSANDO		0x1dd8
+
+static int
+pds_vfio_pci_probe(struct pci_dev *pdev,
+		   const struct pci_device_id *id)
+{
+	struct pds_vfio_pci_device *pds_vfio;
+	int err;
+
+	pds_vfio = vfio_alloc_device(pds_vfio_pci_device, vfio_coredev.vdev,
+				     &pdev->dev,  pds_vfio_ops_info());
+	if (IS_ERR(pds_vfio))
+		return PTR_ERR(pds_vfio);
+
+	dev_set_drvdata(&pdev->dev, &pds_vfio->vfio_coredev);
+	pds_vfio->pdev = pdev;
+
+	err = vfio_pci_core_register_device(&pds_vfio->vfio_coredev);
+	if (err)
+		goto out_put_vdev;
+
+	return 0;
+
+out_put_vdev:
+	vfio_put_device(&pds_vfio->vfio_coredev.vdev);
+	return err;
+}
+
+static void
+pds_vfio_pci_remove(struct pci_dev *pdev)
+{
+	struct pds_vfio_pci_device *pds_vfio = pds_vfio_pci_drvdata(pdev);
+
+	vfio_pci_core_unregister_device(&pds_vfio->vfio_coredev);
+	vfio_put_device(&pds_vfio->vfio_coredev.vdev);
+}
+
+static const struct pci_device_id
+pds_vfio_pci_table[] = {
+	{
+		.class = PCI_CLASS_STORAGE_EXPRESS,
+		.class_mask = 0xffffff,
+		.vendor = PCI_VENDOR_ID_PENSANDO,
+		.device = PCI_DEVICE_ID_PENSANDO_NVME_VF,
+		.subvendor = PCI_ANY_ID,
+		.subdevice = PCI_ANY_ID,
+		.override_only = PCI_ID_F_VFIO_DRIVER_OVERRIDE,
+	},
+	{ 0, }
+};
+MODULE_DEVICE_TABLE(pci, pds_vfio_pci_table);
+
+static struct pci_driver
+pds_vfio_pci_driver = {
+	.name = PDS_VFIO_DRV_NAME,
+	.id_table = pds_vfio_pci_table,
+	.probe = pds_vfio_pci_probe,
+	.remove = pds_vfio_pci_remove,
+	.driver_managed_dma = true,
+};
+
+static void __exit
+pds_vfio_pci_cleanup(void)
+{
+	pci_unregister_driver(&pds_vfio_pci_driver);
+}
+module_exit(pds_vfio_pci_cleanup);
+
+static int __init
+pds_vfio_pci_init(void)
+{
+	int err;
+
+	err = pci_register_driver(&pds_vfio_pci_driver);
+	if (err) {
+		pr_err("pci driver register failed: %pe\n", ERR_PTR(err));
+		return err;
+	}
+
+	return 0;
+}
+module_init(pds_vfio_pci_init);
+
+MODULE_DESCRIPTION(PDS_VFIO_DRV_DESCRIPTION);
+MODULE_AUTHOR("Pensando Systems, Inc");
+MODULE_LICENSE("GPL");
diff --git a/drivers/vfio/pci/pds/vfio_dev.c b/drivers/vfio/pci/pds/vfio_dev.c
new file mode 100644
index 000000000000..f8f4006c0915
--- /dev/null
+++ b/drivers/vfio/pci/pds/vfio_dev.c
@@ -0,0 +1,74 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright(c) 2022 Pensando Systems, Inc */
+
+#include <linux/vfio.h>
+#include <linux/vfio_pci_core.h>
+
+#include "vfio_dev.h"
+
+struct pds_vfio_pci_device *
+pds_vfio_pci_drvdata(struct pci_dev *pdev)
+{
+	struct vfio_pci_core_device *core_device = dev_get_drvdata(&pdev->dev);
+
+	return container_of(core_device, struct pds_vfio_pci_device,
+			    vfio_coredev);
+}
+
+static int
+pds_vfio_init_device(struct vfio_device *vdev)
+{
+	struct pds_vfio_pci_device *pds_vfio =
+		container_of(vdev, struct pds_vfio_pci_device,
+			     vfio_coredev.vdev);
+	struct pci_dev *pdev = to_pci_dev(vdev->dev);
+	int err;
+
+	err = vfio_pci_core_init_dev(vdev);
+	if (err)
+		return err;
+
+	pds_vfio->vf_id = pci_iov_vf_id(pdev);
+	pds_vfio->pci_id = PCI_DEVID(pdev->bus->number, pdev->devfn);
+
+	return 0;
+}
+
+static int
+pds_vfio_open_device(struct vfio_device *vdev)
+{
+	struct pds_vfio_pci_device *pds_vfio =
+		container_of(vdev, struct pds_vfio_pci_device,
+			     vfio_coredev.vdev);
+	int err;
+
+	err = vfio_pci_core_enable(&pds_vfio->vfio_coredev);
+	if (err)
+		return err;
+
+	vfio_pci_core_finish_enable(&pds_vfio->vfio_coredev);
+
+	return 0;
+}
+
+static const struct vfio_device_ops
+pds_vfio_ops = {
+	.name = "pds-vfio",
+	.init = pds_vfio_init_device,
+	.release = vfio_pci_core_release_dev,
+	.open_device = pds_vfio_open_device,
+	.close_device = vfio_pci_core_close_device,
+	.ioctl = vfio_pci_core_ioctl,
+	.device_feature = vfio_pci_core_ioctl_feature,
+	.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,
+};
+
+const struct vfio_device_ops *
+pds_vfio_ops_info(void)
+{
+	return &pds_vfio_ops;
+}
diff --git a/drivers/vfio/pci/pds/vfio_dev.h b/drivers/vfio/pci/pds/vfio_dev.h
new file mode 100644
index 000000000000..289479a08dce
--- /dev/null
+++ b/drivers/vfio/pci/pds/vfio_dev.h
@@ -0,0 +1,23 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright(c) 2022 Pensando Systems, Inc */
+
+#ifndef _VFIO_DEV_H_
+#define _VFIO_DEV_H_
+
+#include <linux/pci.h>
+#include <linux/vfio_pci_core.h>
+
+struct pds_vfio_pci_device {
+	struct vfio_pci_core_device vfio_coredev;
+	struct pci_dev *pdev;
+
+	int vf_id;
+	int pci_id;
+};
+
+const struct vfio_device_ops *
+pds_vfio_ops_info(void);
+struct pds_vfio_pci_device *
+pds_vfio_pci_drvdata(struct pci_dev *pdev);
+
+#endif /* _VFIO_DEV_H_ */
diff --git a/include/linux/pds/pds_core_if.h b/include/linux/pds/pds_core_if.h
index 6e92697657e4..4362b94a7666 100644
--- a/include/linux/pds/pds_core_if.h
+++ b/include/linux/pds/pds_core_if.h
@@ -9,6 +9,7 @@
 #define PCI_VENDOR_ID_PENSANDO			0x1dd8
 #define PCI_DEVICE_ID_PENSANDO_CORE_PF		0x100c
 #define PCI_DEVICE_ID_PENSANDO_VDPA_VF          0x100b
+#define PCI_DEVICE_ID_PENSANDO_NVME_VF		0x1006
 
 #define PDS_CORE_BARS_MAX			4
 #define PDS_CORE_PCI_BAR_DBELL			1
-- 
2.17.1