[PATCH 5/6] vdpa: introduce virtio pci driver

From: Jason Wang <jasowang@redhat.com>
To: mst@redhat.com, jasowang@redhat.com
Cc: kvm@vger.kernel.org, virtualization@lists.linux-foundation.org,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	rob.miller@broadcom.com, lingshan.zhu@intel.com,
	eperezma@redhat.com, lulu@redhat.com, shahafs@mellanox.com,
	hanand@xilinx.com, mhabets@solarflare.com, gdawar@xilinx.com,
	saugatm@xilinx.com, vmireyno@marvell.com,
	zhangweining@ruijie.com.cn, eli@mellanox.com
Subject: [PATCH 5/6] vdpa: introduce virtio pci driver
Date: Fri, 29 May 2020 16:03:02 +0800	[thread overview]
Message-ID: <20200529080303.15449-6-jasowang@redhat.com> (raw)
In-Reply-To: <20200529080303.15449-1-jasowang@redhat.com>

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.

Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 drivers/vdpa/Kconfig           |   6 +
 drivers/vdpa/Makefile          |   1 +
 drivers/vdpa/vp_vdpa/Makefile  |   2 +
 drivers/vdpa/vp_vdpa/vp_vdpa.c | 583 +++++++++++++++++++++++++++++++++
 4 files changed, 592 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..3f1bf8b6723d 100644
--- a/drivers/vdpa/Kconfig
+++ b/drivers/vdpa/Kconfig
@@ -28,4 +28,10 @@ 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.
+
 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..e59c310e2156
--- /dev/null
+++ b/drivers/vdpa/vp_vdpa/vp_vdpa.c
@@ -0,0 +1,583 @@
+// 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@redhat.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];
+	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)
+{
+	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);
+
+	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 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,
+	.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;
+	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);
+	vp_vdpa->notify = map_capability(vp_vdpa, notify);
+	vp_vdpa->common = map_capability(vp_vdpa, common);
+	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;
+	}
+
+	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 const struct pci_device_id vp_vdpa_id_table[] = {
+	{ PCI_DEVICE(PCI_VENDOR_ID_REDHAT_QUMRANET, PCI_ANY_ID) },
+	{ 0 }
+};
+
+MODULE_DEVICE_TABLE(pci, vp_vdpa_id_table);
+
+static struct pci_driver vp_vdpa_driver = {
+	.name		= "vp-vdpa",
+	.id_table	= vp_vdpa_id_table,
+	.probe		= vp_vdpa_probe,
+	.remove		= vp_vdpa_remove,
+};
+
+module_pci_driver(vp_vdpa_driver);
+
+MODULE_AUTHOR("Jason Wang <jasowang@redhat.com>");
+MODULE_DESCRIPTION("vp-vdpa");
+MODULE_LICENSE("GPL");
+MODULE_VERSION("1");
-- 
2.20.1

