[RFC PATCH v4 08/10] i40e/vf_migration: VF live migration - pass-through VF first

[Yan Zhao <yan.y.zhao@intel.com>]

This driver intercepts all device operations as long as it's probed
successfully by vfio-pci driver.

It will process regions and irqs of its interest and then forward
operations to default handlers exported from vfio pci if it wishes to.

In this patch, this driver does nothing but pass through VFs to guest
by calling to exported handlers from driver vfio-pci.

Cc: Shaopeng He <shaopeng.he@intel.com>

Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
---
 drivers/net/ethernet/intel/Kconfig            |  10 ++
 drivers/net/ethernet/intel/i40e/Makefile      |   2 +
 .../ethernet/intel/i40e/i40e_vf_migration.c   | 165 ++++++++++++++++++
 .../ethernet/intel/i40e/i40e_vf_migration.h   |  59 +++++++
 4 files changed, 236 insertions(+)
 create mode 100644 drivers/net/ethernet/intel/i40e/i40e_vf_migration.c
 create mode 100644 drivers/net/ethernet/intel/i40e/i40e_vf_migration.h

diff --git a/drivers/net/ethernet/intel/Kconfig b/drivers/net/ethernet/intel/Kconfig
index ad34e4335df2..31780d9a59f1 100644
--- a/drivers/net/ethernet/intel/Kconfig
+++ b/drivers/net/ethernet/intel/Kconfig
@@ -264,6 +264,16 @@ config I40E_DCB
 
 	  If unsure, say N.
 
+config I40E_VF_MIGRATION
+	tristate "XL710 Family VF live migration support -- loadable modules only"
+	depends on I40E && VFIO_PCI && m
+	help
+	  Say m if you want to enable live migration of
+	  Virtual Functions of Intel(R) Ethernet Controller XL710
+	  Family of devices. It must be a module.
+	  This module serves as vendor module of module vfio_pci.
+	  VFs bind to module vfio_pci directly.
+
 # this is here to allow seamless migration from I40EVF --> IAVF name
 # so that CONFIG_IAVF symbol will always mirror the state of CONFIG_I40EVF
 config IAVF
diff --git a/drivers/net/ethernet/intel/i40e/Makefile b/drivers/net/ethernet/intel/i40e/Makefile
index 2f21b3e89fd0..b80c224c2602 100644
--- a/drivers/net/ethernet/intel/i40e/Makefile
+++ b/drivers/net/ethernet/intel/i40e/Makefile
@@ -27,3 +27,5 @@ i40e-objs := i40e_main.o \
 	i40e_xsk.o
 
 i40e-$(CONFIG_I40E_DCB) += i40e_dcb.o i40e_dcb_nl.o
+
+obj-$(CONFIG_I40E_VF_MIGRATION) += i40e_vf_migration.o
diff --git a/drivers/net/ethernet/intel/i40e/i40e_vf_migration.c b/drivers/net/ethernet/intel/i40e/i40e_vf_migration.c
new file mode 100644
index 000000000000..96026dcf5c9d
--- /dev/null
+++ b/drivers/net/ethernet/intel/i40e/i40e_vf_migration.c
@@ -0,0 +1,165 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright(c) 2013 - 2019 Intel Corporation. */
+
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/vfio.h>
+#include <linux/pci.h>
+#include <linux/eventfd.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/sysfs.h>
+#include <linux/file.h>
+#include <linux/pci.h>
+
+#include "i40e.h"
+#include "i40e_vf_migration.h"
+
+#define VERSION_STRING  "0.1"
+#define DRIVER_AUTHOR   "Intel Corporation"
+
+static int i40e_vf_open(void *device_data)
+{
+	struct i40e_vf_migration *i40e_vf_dev =
+		vfio_pci_vendor_data(device_data);
+	int ret;
+	struct vfio_device_migration_info *mig_ctl = NULL;
+
+	if (!try_module_get(THIS_MODULE))
+		return -ENODEV;
+
+	mutex_lock(&i40e_vf_dev->reflock);
+	if (!i40e_vf_dev->refcnt) {
+		vfio_pci_set_vendor_regions(device_data, 0);
+		vfio_pci_set_vendor_irqs(device_data, 0);
+	}
+
+	ret = vfio_pci_open(device_data);
+	if (ret)
+		goto error;
+
+	i40e_vf_dev->refcnt++;
+	mutex_unlock(&i40e_vf_dev->reflock);
+	return 0;
+error:
+	if (!i40e_vf_dev->refcnt) {
+		vfio_pci_set_vendor_regions(device_data, 0);
+		vfio_pci_set_vendor_irqs(device_data, 0);
+	}
+	module_put(THIS_MODULE);
+	mutex_unlock(&i40e_vf_dev->reflock);
+	return ret;
+}
+
+void i40e_vf_release(void *device_data)
+{
+	struct i40e_vf_migration *i40e_vf_dev =
+		vfio_pci_vendor_data(device_data);
+
+	mutex_lock(&i40e_vf_dev->reflock);
+	if (!--i40e_vf_dev->refcnt) {
+		vfio_pci_set_vendor_regions(device_data, 0);
+		vfio_pci_set_vendor_irqs(device_data, 0);
+	}
+	vfio_pci_release(device_data);
+	mutex_unlock(&i40e_vf_dev->reflock);
+	module_put(THIS_MODULE);
+}
+
+static long i40e_vf_ioctl(void *device_data,
+			  unsigned int cmd, unsigned long arg)
+{
+	return vfio_pci_ioctl(device_data, cmd, arg);
+}
+
+static ssize_t i40e_vf_read(void *device_data, char __user *buf,
+			    size_t count, loff_t *ppos)
+{
+	return vfio_pci_read(device_data, buf, count, ppos);
+}
+
+static ssize_t i40e_vf_write(void *device_data, const char __user *buf,
+			     size_t count, loff_t *ppos)
+{
+	return vfio_pci_write(device_data, buf, count, ppos);
+}
+
+static int i40e_vf_mmap(void *device_data, struct vm_area_struct *vma)
+{
+	return vfio_pci_mmap(device_data, vma);
+}
+
+static void i40e_vf_request(void *device_data, unsigned int count)
+{
+	vfio_pci_request(device_data, count);
+}
+
+static struct vfio_device_ops i40e_vf_device_ops_node = {
+	.name		= "i40e_vf",
+	.open		= i40e_vf_open,
+	.release	= i40e_vf_release,
+	.ioctl		= i40e_vf_ioctl,
+	.read		= i40e_vf_read,
+	.write		= i40e_vf_write,
+	.mmap		= i40e_vf_mmap,
+	.request	= i40e_vf_request,
+};
+
+void *i40e_vf_probe(struct pci_dev *pdev)
+{
+	struct i40e_vf_migration *i40e_vf_dev = NULL;
+	struct pci_dev *pf_dev, *vf_dev;
+	struct i40e_pf *pf;
+	struct i40e_vf *vf;
+	unsigned int vf_devfn, devfn;
+	int vf_id = -1;
+	int i;
+
+	pf_dev = pdev->physfn;
+	pf = pci_get_drvdata(pf_dev);
+	vf_dev = pdev;
+	vf_devfn = vf_dev->devfn;
+
+	for (i = 0; i < pci_num_vf(pf_dev); i++) {
+		devfn = (pf_dev->devfn + pf_dev->sriov->offset +
+			 pf_dev->sriov->stride * i) & 0xff;
+		if (devfn == vf_devfn) {
+			vf_id = i;
+			break;
+		}
+	}
+
+	if (vf_id == -1)
+		return ERR_PTR(-EINVAL);
+
+	i40e_vf_dev = kzalloc(sizeof(*i40e_vf_dev), GFP_KERNEL);
+
+	if (!i40e_vf_dev)
+		return ERR_PTR(-ENOMEM);
+
+	i40e_vf_dev->vf_id = vf_id;
+	i40e_vf_dev->vf_vendor = pdev->vendor;
+	i40e_vf_dev->vf_device = pdev->device;
+	i40e_vf_dev->pf_dev = pf_dev;
+	i40e_vf_dev->vf_dev = vf_dev;
+	mutex_init(&i40e_vf_dev->reflock);
+
+	vf = &pf->vf[vf_id];
+
+	return i40e_vf_dev;
+}
+
+static void i40e_vf_remove(void *vendor_data)
+{
+	kfree(vendor_data);
+}
+
+#define i40e_vf_device_ops (&i40e_vf_device_ops_node)
+module_vfio_pci_register_vendor_handler("I40E VF", i40e_vf_probe,
+					i40e_vf_remove, i40e_vf_device_ops);
+
+MODULE_ALIAS("vfio-pci:8086-154c");
+MODULE_LICENSE("GPL v2");
+MODULE_INFO(supported, "Vendor driver of vfio pci to support VF live migration");
+MODULE_VERSION(VERSION_STRING);
+MODULE_AUTHOR(DRIVER_AUTHOR);
diff --git a/drivers/net/ethernet/intel/i40e/i40e_vf_migration.h b/drivers/net/ethernet/intel/i40e/i40e_vf_migration.h
new file mode 100644
index 000000000000..696d40601ec3
--- /dev/null
+++ b/drivers/net/ethernet/intel/i40e/i40e_vf_migration.h
@@ -0,0 +1,59 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright(c) 2013 - 2019 Intel Corporation. */
+
+#ifndef I40E_MIG_H
+#define I40E_MIG_H
+
+#include <linux/pci.h>
+#include <linux/vfio.h>
+#include <linux/mdev.h>
+
+#include "i40e.h"
+#include "i40e_txrx.h"
+
+/* helper macros copied from vfio-pci */
+#define VFIO_PCI_OFFSET_SHIFT   40
+#define VFIO_PCI_OFFSET_TO_INDEX(off)   ((off) >> VFIO_PCI_OFFSET_SHIFT)
+#define VFIO_PCI_INDEX_TO_OFFSET(index)	((u64)(index) << VFIO_PCI_OFFSET_SHIFT)
+#define VFIO_PCI_OFFSET_MASK    (((u64)(1) << VFIO_PCI_OFFSET_SHIFT) - 1)
+
+/* Single Root I/O Virtualization */
+struct pci_sriov {
+	int		pos;		/* Capability position */
+	int		nres;		/* Number of resources */
+	u32		cap;		/* SR-IOV Capabilities */
+	u16		ctrl;		/* SR-IOV Control */
+	u16		total_VFs;	/* Total VFs associated with the PF */
+	u16		initial_VFs;	/* Initial VFs associated with the PF */
+	u16		num_VFs;	/* Number of VFs available */
+	u16		offset;		/* First VF Routing ID offset */
+	u16		stride;		/* Following VF stride */
+	u16		vf_device;	/* VF device ID */
+	u32		pgsz;		/* Page size for BAR alignment */
+	u8		link;		/* Function Dependency Link */
+	u8		max_VF_buses;	/* Max buses consumed by VFs */
+	u16		driver_max_VFs;	/* Max num VFs driver supports */
+	struct pci_dev	*dev;		/* Lowest numbered PF */
+	struct pci_dev	*self;		/* This PF */
+	u32		cfg_size;	/* VF config space size */
+	u32		class;		/* VF device */
+	u8		hdr_type;	/* VF header type */
+	u16		subsystem_vendor; /* VF subsystem vendor */
+	u16		subsystem_device; /* VF subsystem device */
+	resource_size_t	barsz[PCI_SRIOV_NUM_BARS];	/* VF BAR size */
+	bool		drivers_autoprobe; /* Auto probing of VFs by driver */
+};
+
+struct i40e_vf_migration {
+	__u32				vf_vendor;
+	__u32				vf_device;
+	__u32				handle;
+	struct pci_dev			*pf_dev;
+	struct pci_dev			*vf_dev;
+	int				vf_id;
+	int				refcnt;
+	struct				mutex reflock; /*mutex protect refcnt */
+};
+
+#endif /* I40E_MIG_H */
+
-- 
2.17.1