Re: [PATCH RESEND V2] vdpa: introduce virtio pci driver

From: Michael S. Tsirkin
Date: Wed Jun 10 2020 - 02:08:04 EST

On Wed, Jun 10, 2020 at 01:49:51PM +0800, Jason Wang wrote:
> 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@xxxxxxxxxx>

error: sha1 information is lacking or useless (drivers/vdpa/Kconfig).

which tree is this on top of?

> ---
> 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@xxxxxxxxxx>
> + *
> + * 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 ânaturalâ 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@xxxxxxxxxx>");
> +MODULE_DESCRIPTION("vp-vdpa");
> +MODULE_LICENSE("GPL");
> +MODULE_VERSION("1");
> --
> 2.20.1