Date:   Wed, 10 Jun 2020 11:59:20 +0800
From:   Jason Wang <jasowang@...hat.com>
To:     mst@...hat.com
Cc:     linux-kernel@...r.kernel.org,
        virtualization@...ts.linux-foundation.org, rob.miller@...adcom.com,
        lingshan.zhu@...el.com, eperezma@...hat.com, lulu@...hat.com,
        shahafs@...lanox.com, hanand@...inx.com, mhabets@...arflare.com,
        gdawar@...inx.com, saugatm@...inx.com, vmireyno@...vell.com,
        zhangweining@...jie.com.cn, eli@...lanox.com,
        Jason Wang <jasowang@...hat.com>
Subject: [PATCH V2] vdpa: introduce virtio pci driver

This patch introduce a vDPA driver for virtio-pci device. It bridges
the virtio-pci control command to the vDPA bus. This will be used for
developing new features for both software vDPA framework and hardware
vDPA feature.

Compared to vdpa_sim, it has several advantages:

- it's a real device driver which allow us to play with real hardware
  features
- type independent instead of networking specific

Note that since virtio specification does not support get/restore
virtqueue state. So we can not use this driver for VM. This can be
addressed by extending the virtio specification.

Consider the driver is mainly for testing and development for vDPA
features, it can only be bound via dynamic ids to make sure it's not
conflict with the drivers like virtio-pci or IFCVF.

Signed-off-by: Jason Wang <jasowang@...hat.com>
---
Changes since V1:
- use NULL id_table to allow dynamic ids only
- squash the doorbell reporting
---
 drivers/vdpa/Kconfig           |   8 +
 drivers/vdpa/Makefile          |   1 +
 drivers/vdpa/vp_vdpa/Makefile  |   2 +
 drivers/vdpa/vp_vdpa/vp_vdpa.c | 601 +++++++++++++++++++++++++++++++++
 4 files changed, 612 insertions(+)
 create mode 100644 drivers/vdpa/vp_vdpa/Makefile
 create mode 100644 drivers/vdpa/vp_vdpa/vp_vdpa.c

diff --git a/drivers/vdpa/Kconfig b/drivers/vdpa/Kconfig
index e8140065c8a5..5cef3a4872e3 100644
--- a/drivers/vdpa/Kconfig
+++ b/drivers/vdpa/Kconfig
@@ -28,4 +28,12 @@ config IFCVF
 	  To compile this driver as a module, choose M here: the module will
 	  be called ifcvf.
 
+config VP_VDPA
+	tristate "Virtio PCI bridge vDPA driver"
+	depends on PCI_MSI
+	help
+	  This kernel module that bridges virtio PCI device to vDPA
+	  bus. It allows us to test and develop vDPA subsystem inside
+	  an VM with the emulated virtio-pci device
+
 endif # VDPA
diff --git a/drivers/vdpa/Makefile b/drivers/vdpa/Makefile
index 8bbb686ca7a2..37d00f49b3bf 100644
--- a/drivers/vdpa/Makefile
+++ b/drivers/vdpa/Makefile
@@ -2,3 +2,4 @@
 obj-$(CONFIG_VDPA) += vdpa.o
 obj-$(CONFIG_VDPA_SIM) += vdpa_sim/
 obj-$(CONFIG_IFCVF)    += ifcvf/
+obj-$(CONFIG_VP_VDPA)    += vp_vdpa/
diff --git a/drivers/vdpa/vp_vdpa/Makefile b/drivers/vdpa/vp_vdpa/Makefile
new file mode 100644
index 000000000000..231088d3af7d
--- /dev/null
+++ b/drivers/vdpa/vp_vdpa/Makefile
@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_VP_VDPA) += vp_vdpa.o
diff --git a/drivers/vdpa/vp_vdpa/vp_vdpa.c b/drivers/vdpa/vp_vdpa/vp_vdpa.c
new file mode 100644
index 000000000000..2070298ab9fc
--- /dev/null
+++ b/drivers/vdpa/vp_vdpa/vp_vdpa.c
@@ -0,0 +1,601 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * vDPA bridge driver for modern virtio-pci device
+ *
+ * Copyright (c) 2020, Red Hat Inc. All rights reserved.
+ * Author: Jason Wang <jasowang@...hat.com>
+ *
+ * Based on virtio_pci_modern.c.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/vdpa.h>
+#include <linux/virtio.h>
+#include <linux/virtio_config.h>
+#include <linux/virtio_ring.h>
+#include <linux/virtio_pci.h>
+
+/* TBD: read from config space */
+#define VP_VDPA_MAX_QUEUE 2
+#define VP_VDPA_DRIVER_NAME "vp_vdpa"
+
+#define VP_VDPA_FEATURES \
+	((1ULL << VIRTIO_F_ANY_LAYOUT)			| \
+	 (1ULL << VIRTIO_F_VERSION_1)			| \
+	 (1ULL << VIRTIO_F_ORDER_PLATFORM)		| \
+	 (1ULL << VIRTIO_F_IOMMU_PLATFORM))
+
+struct vp_vring {
+	void __iomem *notify;
+	char msix_name[256];
+	resource_size_t notify_pa;
+	struct vdpa_callback cb;
+	int irq;
+};
+
+struct vp_vdpa {
+	struct vdpa_device vdpa;
+	struct pci_dev *pdev;
+
+	struct virtio_device_id id;
+
+	struct vp_vring vring[VP_VDPA_MAX_QUEUE];
+
+	/* The IO mapping for the PCI config space */
+	void __iomem * const *base;
+	struct virtio_pci_common_cfg __iomem *common;
+	void __iomem *device;
+	/* Base of vq notifications */
+	void __iomem *notify;
+
+	/* Multiplier for queue_notify_off. */
+	u32 notify_off_multiplier;
+
+	int modern_bars;
+	int vectors;
+};
+
+static struct vp_vdpa *vdpa_to_vp(struct vdpa_device *vdpa)
+{
+	return container_of(vdpa, struct vp_vdpa, vdpa);
+}
+
+/*
+ * Type-safe wrappers for io accesses.
+ * Use these to enforce at compile time the following spec requirement:
+ *
+ * The driver MUST access each field using the “natural” access
+ * method, i.e. 32-bit accesses for 32-bit fields, 16-bit accesses
+ * for 16-bit fields and 8-bit accesses for 8-bit fields.
+ */
+static inline u8 vp_ioread8(u8 __iomem *addr)
+{
+	return ioread8(addr);
+}
+static inline u16 vp_ioread16(__le16 __iomem *addr)
+{
+	return ioread16(addr);
+}
+
+static inline u32 vp_ioread32(__le32 __iomem *addr)
+{
+	return ioread32(addr);
+}
+
+static inline void vp_iowrite8(u8 value, u8 __iomem *addr)
+{
+	iowrite8(value, addr);
+}
+
+static inline void vp_iowrite16(u16 value, __le16 __iomem *addr)
+{
+	iowrite16(value, addr);
+}
+
+static inline void vp_iowrite32(u32 value, __le32 __iomem *addr)
+{
+	iowrite32(value, addr);
+}
+
+static void vp_iowrite64_twopart(u64 val,
+				 __le32 __iomem *lo, __le32 __iomem *hi)
+{
+	vp_iowrite32((u32)val, lo);
+	vp_iowrite32(val >> 32, hi);
+}
+
+static int find_capability(struct pci_dev *dev, u8 cfg_type,
+			   u32 ioresource_types, int *bars)
+{
+	int pos;
+
+	for (pos = pci_find_capability(dev, PCI_CAP_ID_VNDR);
+	     pos > 0;
+	     pos = pci_find_next_capability(dev, pos, PCI_CAP_ID_VNDR)) {
+		u8 type, bar;
+
+		pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
+							 cfg_type),
+				     &type);
+		pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
+							 bar),
+				     &bar);
+
+		/* Ignore structures with reserved BAR values */
+		if (bar > 0x5)
+			continue;
+
+		if (type == cfg_type) {
+			if (pci_resource_len(dev, bar) &&
+			    pci_resource_flags(dev, bar) & ioresource_types) {
+				*bars |= (1 << bar);
+				return pos;
+			}
+		}
+	}
+	return 0;
+}
+
+static void __iomem *map_capability(struct vp_vdpa *vp_vdpa, int off,
+				    resource_size_t *pa)
+{
+	struct pci_dev *pdev = vp_vdpa->pdev;
+	u32 offset;
+	u8 bar;
+
+	pci_read_config_byte(pdev,
+			     off + offsetof(struct virtio_pci_cap, bar),
+			     &bar);
+	pci_read_config_dword(pdev,
+			      off + offsetof(struct virtio_pci_cap, offset),
+			      &offset);
+
+	if (pa)
+		*pa = pci_resource_start(pdev, bar) + offset;
+
+	return vp_vdpa->base[bar] + offset;
+}
+
+static u64 vp_vdpa_get_features(struct vdpa_device *vdpa)
+{
+	struct vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa);
+	u64 features;
+
+	vp_iowrite32(0, &vp_vdpa->common->device_feature_select);
+	features = vp_ioread32(&vp_vdpa->common->device_feature);
+	vp_iowrite32(1, &vp_vdpa->common->device_feature_select);
+	features |= ((u64)vp_ioread32(&vp_vdpa->common->device_feature) << 32);
+	features &= VP_VDPA_FEATURES;
+
+	return features;
+}
+
+static int vp_vdpa_set_features(struct vdpa_device *vdpa, u64 features)
+{
+	struct vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa);
+
+	vp_iowrite32(0, &vp_vdpa->common->guest_feature_select);
+	vp_iowrite32((u32)features, &vp_vdpa->common->guest_feature);
+	vp_iowrite32(1, &vp_vdpa->common->guest_feature_select);
+	vp_iowrite32(features >> 32, &vp_vdpa->common->guest_feature);
+
+	return 0;
+}
+
+static u8 vp_vdpa_get_status(struct vdpa_device *vdpa)
+{
+	struct vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa);
+
+	return vp_ioread8(&vp_vdpa->common->device_status);
+}
+
+static void vp_vdpa_free_irq(struct vp_vdpa *vp_vdpa)
+{
+	struct pci_dev *pdev = vp_vdpa->pdev;
+	int i;
+
+	for (i = 0; i < VP_VDPA_MAX_QUEUE; i++) {
+		if (vp_vdpa->vring[i].irq != -1) {
+			vp_iowrite16(i, &vp_vdpa->common->queue_select);
+			vp_iowrite16(VIRTIO_MSI_NO_VECTOR,
+				     &vp_vdpa->common->queue_msix_vector);
+			devm_free_irq(&pdev->dev, vp_vdpa->vring[i].irq,
+				      &vp_vdpa->vring[i]);
+			vp_vdpa->vring[i].irq = -1;
+		}
+	}
+
+	if (vp_vdpa->vectors) {
+		pci_free_irq_vectors(pdev);
+		vp_vdpa->vectors = 0;
+	}
+}
+
+static irqreturn_t vp_vdpa_intr_handler(int irq, void *arg)
+{
+	struct vp_vring *vring = arg;
+
+	if (vring->cb.callback)
+		return vring->cb.callback(vring->cb.private);
+
+	return IRQ_HANDLED;
+}
+
+static int vp_vdpa_request_irq(struct vp_vdpa *vp_vdpa)
+{
+	struct pci_dev *pdev = vp_vdpa->pdev;
+	int i, ret, irq;
+
+	ret = pci_alloc_irq_vectors(pdev, VP_VDPA_MAX_QUEUE,
+				    VP_VDPA_MAX_QUEUE, PCI_IRQ_MSIX);
+	if (ret != VP_VDPA_MAX_QUEUE) {
+		dev_err(&pdev->dev, "vp_vdpa: fail to allocate irq vectors\n");
+		return ret;
+	}
+
+	vp_vdpa->vectors = VP_VDPA_MAX_QUEUE;
+
+	for (i = 0; i < VP_VDPA_MAX_QUEUE; i++) {
+		snprintf(vp_vdpa->vring[i].msix_name, 256,
+			"vp-vdpa[%s]-%d\n", pci_name(pdev), i);
+		irq = pci_irq_vector(pdev, i);
+		ret = devm_request_irq(&pdev->dev, irq,
+				       vp_vdpa_intr_handler,
+				       0, vp_vdpa->vring[i].msix_name,
+				       &vp_vdpa->vring[i]);
+		if (ret) {
+			dev_err(&pdev->dev, "vp_vdpa: fail to request irq for vq %d\n",
+				i);
+			goto err;
+		}
+		vp_iowrite16(i, &vp_vdpa->common->queue_select);
+		vp_iowrite16(i, &vp_vdpa->common->queue_msix_vector);
+		vp_vdpa->vring[i].irq = irq;
+	}
+
+	return 0;
+err:
+	vp_vdpa_free_irq(vp_vdpa);
+	return ret;
+}
+
+static void vp_vdpa_set_status(struct vdpa_device *vdpa, u8 status)
+{
+	struct vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa);
+	u8 s = vp_vdpa_get_status(vdpa);
+
+	if (status & VIRTIO_CONFIG_S_DRIVER_OK &&
+	    !(s & VIRTIO_CONFIG_S_DRIVER_OK)) {
+		vp_vdpa_request_irq(vp_vdpa);
+	}
+
+	vp_iowrite8(status, &vp_vdpa->common->device_status);
+
+	if (!(status & VIRTIO_CONFIG_S_DRIVER_OK) &&
+	    (s & VIRTIO_CONFIG_S_DRIVER_OK))
+		vp_vdpa_free_irq(vp_vdpa);
+}
+
+static u16 vp_vdpa_get_vq_num_max(struct vdpa_device *vdpa)
+{
+	struct vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa);
+
+	return vp_ioread16(&vp_vdpa->common->queue_size);
+}
+
+static u64 vp_vdpa_get_vq_state(struct vdpa_device *vdpa, u16 qid)
+{
+	return 0;
+}
+
+static struct vdpa_notification_area
+vp_vdpa_get_vq_notification(struct vdpa_device *vdpa, u16 qid)
+{
+	struct vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa);
+	struct vdpa_notification_area notify;
+
+	notify.addr = vp_vdpa->vring[qid].notify_pa;
+	notify.size = vp_vdpa->notify_off_multiplier;
+
+	return notify;
+}
+
+static int vp_vdpa_set_vq_state(struct vdpa_device *vdpa, u16 qid,
+				u64 num)
+{
+	/* Note that this is not supported by virtio specification, so
+	 * we return -ENOTSUPP here. This means we can't support live
+	 * migration, vhost device start/stop.
+	 */
+
+	return -ENOTSUPP;
+}
+
+static void vp_vdpa_set_vq_cb(struct vdpa_device *vdpa, u16 qid,
+			      struct vdpa_callback *cb)
+{
+	struct vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa);
+
+	vp_vdpa->vring[qid].cb = *cb;
+}
+
+static void vp_vdpa_set_vq_ready(struct vdpa_device *vdpa,
+				 u16 qid, bool ready)
+{
+	struct vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa);
+
+	vp_iowrite16(qid, &vp_vdpa->common->queue_select);
+	vp_iowrite16(ready, &vp_vdpa->common->queue_enable);
+}
+
+static bool vp_vdpa_get_vq_ready(struct vdpa_device *vdpa, u16 qid)
+{
+	struct vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa);
+
+	vp_iowrite16(qid, &vp_vdpa->common->queue_select);
+
+	return vp_ioread16(&vp_vdpa->common->queue_enable);
+}
+
+static void vp_vdpa_set_vq_num(struct vdpa_device *vdpa, u16 qid,
+			       u32 num)
+{
+	struct vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa);
+
+	vp_iowrite16(num, &vp_vdpa->common->queue_size);
+}
+
+static int vp_vdpa_set_vq_address(struct vdpa_device *vdpa, u16 qid,
+				  u64 desc_area, u64 driver_area,
+				  u64 device_area)
+{
+	struct vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa);
+	struct virtio_pci_common_cfg __iomem *cfg = vp_vdpa->common;
+
+	vp_iowrite16(qid, &cfg->queue_select);
+	vp_iowrite64_twopart(desc_area,
+			     &cfg->queue_desc_lo, &cfg->queue_desc_hi);
+	vp_iowrite64_twopart(driver_area,
+			     &cfg->queue_avail_lo, &cfg->queue_avail_hi);
+	vp_iowrite64_twopart(device_area,
+			     &cfg->queue_used_lo, &cfg->queue_used_hi);
+
+	return 0;
+}
+
+static void vp_vdpa_kick_vq(struct vdpa_device *vdpa, u16 qid)
+{
+	struct vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa);
+
+	vp_iowrite16(qid, vp_vdpa->vring[qid].notify);
+}
+
+static u32 vp_vdpa_get_generation(struct vdpa_device *vdpa)
+{
+	struct vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa);
+
+	return vp_ioread8(&vp_vdpa->common->config_generation);
+}
+
+static u32 vp_vdpa_get_device_id(struct vdpa_device *vdpa)
+{
+	struct vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa);
+
+	return vp_vdpa->id.device;
+}
+
+static u32 vp_vdpa_get_vendor_id(struct vdpa_device *vdpa)
+{
+	struct vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa);
+
+	return vp_vdpa->id.vendor;
+}
+
+static u32 vp_vdpa_get_vq_align(struct vdpa_device *vdpa)
+{
+	return PAGE_SIZE;
+}
+
+static void vp_vdpa_get_config(struct vdpa_device *vdpa,
+			       unsigned int offset,
+			       void *buf, unsigned int len)
+{
+	struct vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa);
+	u8 old, new;
+	u8 *p;
+	int i;
+
+	do {
+		old = vp_ioread8(&vp_vdpa->common->config_generation);
+		p = buf;
+		for (i = 0; i < len; i++)
+			*p++ = vp_ioread8(vp_vdpa->device + offset + i);
+
+		new = vp_ioread8(&vp_vdpa->common->config_generation);
+	} while (old != new);
+}
+
+static void vp_vdpa_set_config(struct vdpa_device *vdpa,
+			       unsigned int offset, const void *buf,
+			       unsigned int len)
+{
+	struct vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa);
+	const u8 *p = buf;
+	int i;
+
+	for (i = 0; i < len; i++)
+		vp_iowrite8(*p++, vp_vdpa->device + offset + i);
+}
+
+static void vp_vdpa_set_config_cb(struct vdpa_device *vdpa,
+				  struct vdpa_callback *cb)
+{
+	/* We don't support config interrupt */
+}
+
+static const struct vdpa_config_ops vp_vdpa_ops = {
+	.get_features	= vp_vdpa_get_features,
+	.set_features	= vp_vdpa_set_features,
+	.get_status	= vp_vdpa_get_status,
+	.set_status	= vp_vdpa_set_status,
+	.get_vq_num_max	= vp_vdpa_get_vq_num_max,
+	.get_vq_state	= vp_vdpa_get_vq_state,
+	.get_vq_notification = vp_vdpa_get_vq_notification,
+	.set_vq_state	= vp_vdpa_set_vq_state,
+	.set_vq_cb	= vp_vdpa_set_vq_cb,
+	.set_vq_ready	= vp_vdpa_set_vq_ready,
+	.get_vq_ready	= vp_vdpa_get_vq_ready,
+	.set_vq_num	= vp_vdpa_set_vq_num,
+	.set_vq_address	= vp_vdpa_set_vq_address,
+	.kick_vq	= vp_vdpa_kick_vq,
+	.get_generation	= vp_vdpa_get_generation,
+	.get_device_id	= vp_vdpa_get_device_id,
+	.get_vendor_id	= vp_vdpa_get_vendor_id,
+	.get_vq_align	= vp_vdpa_get_vq_align,
+	.get_config	= vp_vdpa_get_config,
+	.set_config	= vp_vdpa_set_config,
+	.set_config_cb  = vp_vdpa_set_config_cb,
+};
+
+static int vp_vdpa_probe(struct pci_dev *pdev, const struct pci_device_id *id)
+{
+	struct device *dev = &pdev->dev;
+	struct vp_vdpa *vp_vdpa;
+	int common, notify, device, ret, i;
+	struct virtio_device_id virtio_id;
+	resource_size_t notify_pa;
+	u16 notify_off;
+
+	/* We only own devices >= 0x1000 and <= 0x107f: leave the rest. */
+	if (pdev->device < 0x1000 || pdev->device > 0x107f)
+		return -ENODEV;
+
+	if (pdev->device < 0x1040) {
+		/* Transitional devices: use the PCI subsystem device id as
+		 * virtio device id, same as legacy driver always did.
+		 */
+		virtio_id.device = pdev->subsystem_device;
+	} else {
+		/* Modern devices: simply use PCI device id,
+		 * but start from 0x1040.
+		 */
+		virtio_id.device = pdev->device - 0x1040;
+	}
+	virtio_id.vendor = pdev->subsystem_vendor;
+
+	ret = pcim_enable_device(pdev);
+	if (ret) {
+		dev_err(dev, "vp_vdpa: Fail to enable PCI device\n");
+		return ret;
+	}
+
+	vp_vdpa = vdpa_alloc_device(struct vp_vdpa, vdpa,
+				    dev, &vp_vdpa_ops);
+	if (vp_vdpa == NULL) {
+		dev_err(dev, "vp_vdpa: Failed to allocate vDPA structure\n");
+		return -ENOMEM;
+	}
+
+	pci_set_master(pdev);
+	pci_set_drvdata(pdev, vp_vdpa);
+
+	vp_vdpa->pdev = pdev;
+	vp_vdpa->vdpa.dma_dev = &pdev->dev;
+
+	common = find_capability(pdev, VIRTIO_PCI_CAP_COMMON_CFG,
+				 IORESOURCE_IO | IORESOURCE_MEM,
+				 &vp_vdpa->modern_bars);
+	if (!common) {
+		dev_err(&pdev->dev,
+			"vp_vdpa: legacy device is not supported\n");
+		ret = -ENODEV;
+		goto err;
+	}
+
+	notify = find_capability(pdev, VIRTIO_PCI_CAP_NOTIFY_CFG,
+				 IORESOURCE_IO | IORESOURCE_MEM,
+				 &vp_vdpa->modern_bars);
+	if (!notify) {
+		dev_err(&pdev->dev,
+			"vp_vdpa: missing notification capabilities\n");
+		ret = -EINVAL;
+		goto err;
+	}
+
+	device = find_capability(pdev, VIRTIO_PCI_CAP_DEVICE_CFG,
+				 IORESOURCE_IO | IORESOURCE_MEM,
+				 &vp_vdpa->modern_bars);
+	if (!device) {
+		dev_err(&pdev->dev,
+			"vp_vdpa: missing device capabilities\n");
+		ret = -EINVAL;
+		goto err;
+	}
+
+	ret = pcim_iomap_regions(pdev, vp_vdpa->modern_bars,
+				 VP_VDPA_DRIVER_NAME);
+	if (ret)
+		goto err;
+
+	vp_vdpa->base = pcim_iomap_table(pdev);
+
+	ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
+	if (ret)
+		ret = dma_set_mask_and_coherent(&pdev->dev,
+						DMA_BIT_MASK(32));
+	if (ret)
+		dev_warn(&pdev->dev, "Failed to enable 64-bit or 32-bit DMA.  Trying to continue, but this might not work.\n");
+
+	vp_vdpa->device = map_capability(vp_vdpa, device, NULL);
+	vp_vdpa->notify = map_capability(vp_vdpa, notify, &notify_pa);
+	vp_vdpa->common = map_capability(vp_vdpa, common, NULL);
+	vp_vdpa->id = virtio_id;
+
+	ret = vdpa_register_device(&vp_vdpa->vdpa);
+	if (ret) {
+		dev_err(&pdev->dev, "Failed to register to vdpa bus\n");
+		goto err;
+	}
+
+	pci_read_config_dword(pdev, notify + sizeof(struct virtio_pci_cap),
+			      &vp_vdpa->notify_off_multiplier);
+
+	for (i = 0; i < VP_VDPA_MAX_QUEUE; i++) {
+		vp_iowrite16(i, &vp_vdpa->common->queue_select);
+		notify_off = vp_ioread16(&vp_vdpa->common->queue_notify_off);
+		vp_vdpa->vring[i].irq = -1;
+		vp_vdpa->vring[i].notify = vp_vdpa->notify +
+			notify_off * vp_vdpa->notify_off_multiplier;
+		vp_vdpa->vring[i].notify_pa = notify_pa +
+			notify_off * vp_vdpa->notify_off_multiplier;
+	}
+
+	return 0;
+
+err:
+	put_device(&vp_vdpa->vdpa.dev);
+	return ret;
+}
+
+static void vp_vdpa_remove(struct pci_dev *pdev)
+{
+	struct vp_vdpa *vp_vdpa = pci_get_drvdata(pdev);
+
+	vdpa_unregister_device(&vp_vdpa->vdpa);
+}
+
+static struct pci_driver vp_vdpa_driver = {
+	.name		= "vp-vdpa",
+	.id_table	= NULL, /* only dynamic ids */
+	.probe		= vp_vdpa_probe,
+	.remove		= vp_vdpa_remove,
+};
+
+module_pci_driver(vp_vdpa_driver);
+
+MODULE_AUTHOR("Jason Wang <jasowang@...hat.com>");
+MODULE_DESCRIPTION("vp-vdpa");
+MODULE_LICENSE("GPL");
+MODULE_VERSION("1");
-- 
2.20.1

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