Message-ID: <aaf5e339-794e-d219-cf62-864473b4fbbd@redhat.com>
Date:   Mon, 22 Feb 2021 17:30:33 +0800
From:   Jason Wang <jasowang@...hat.com>
To:     Stefano Garzarella <sgarzare@...hat.com>
Cc:     mst@...hat.com, virtualization@...ts.linux-foundation.org,
        linux-kernel@...r.kernel.org, shahafs@...lanox.com,
        lulu@...hat.com, rdunlap@...radead.org
Subject: Re: [PATCH V4 2/2] vdpa: introduce virtio pci driver


On 2021/2/22 5:04 下午, Stefano Garzarella wrote:
> On Sat, Feb 20, 2021 at 04:46:29PM +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
>> features prototyping and testing.
>>
>> Note that get/restore virtqueue state is not supported which needs
>> extension on the virtio specification.
>>
>> Signed-off-by: Jason Wang <jasowang@...hat.com>
>> ---
>> drivers/vdpa/Kconfig              |   7 +
>> drivers/vdpa/Makefile             |   1 +
>> drivers/vdpa/virtio_pci/Makefile  |   2 +
>> drivers/vdpa/virtio_pci/vp_vdpa.c | 456 ++++++++++++++++++++++++++++++
>> 4 files changed, 466 insertions(+)
>> create mode 100644 drivers/vdpa/virtio_pci/Makefile
>> create mode 100644 drivers/vdpa/virtio_pci/vp_vdpa.c
>>
>> diff --git a/drivers/vdpa/Kconfig b/drivers/vdpa/Kconfig
>> index ffd1e098bfd2..aa4fa5a6ebcb 100644
>> --- a/drivers/vdpa/Kconfig
>> +++ b/drivers/vdpa/Kconfig
>> @@ -52,4 +52,11 @@ config MLX5_VDPA_NET
>>       be executed by the hardware. It also supports a variety of 
>> stateless
>>       offloads depending on the actual device used and firmware version.
>>
>> +config VP_VDPA
>> +    tristate "Virtio PCI bridge vDPA driver"
>> +        select VIRTIO_PCI_MODERN
>   ^^^^^^^^
> checkpatch doesn't say anything, but here there are spaces instead of 
> a tab.
> I don't know if it's mandatory, but I would replace it because the 
> rest of the file uses tabs.


Yes, will fix.


>
>> +    depends on PCI_MSI
>> +    help
>> +      This kernel module bridges virtio PCI device to vDPA bus.
>> +
>> endif # VDPA
>> diff --git a/drivers/vdpa/Makefile b/drivers/vdpa/Makefile
>> index d160e9b63a66..67fe7f3d6943 100644
>> --- a/drivers/vdpa/Makefile
>> +++ b/drivers/vdpa/Makefile
>> @@ -3,3 +3,4 @@ obj-$(CONFIG_VDPA) += vdpa.o
>> obj-$(CONFIG_VDPA_SIM) += vdpa_sim/
>> obj-$(CONFIG_IFCVF)    += ifcvf/
>> obj-$(CONFIG_MLX5_VDPA) += mlx5/
>> +obj-$(CONFIG_VP_VDPA)    += virtio_pci/
>> diff --git a/drivers/vdpa/virtio_pci/Makefile 
>> b/drivers/vdpa/virtio_pci/Makefile
>> new file mode 100644
>> index 000000000000..231088d3af7d
>> --- /dev/null
>> +++ b/drivers/vdpa/virtio_pci/Makefile
>> @@ -0,0 +1,2 @@
>> +# SPDX-License-Identifier: GPL-2.0
>> +obj-$(CONFIG_VP_VDPA) += vp_vdpa.o
>> diff --git a/drivers/vdpa/virtio_pci/vp_vdpa.c 
>> b/drivers/vdpa/virtio_pci/vp_vdpa.c
>> new file mode 100644
>> index 000000000000..92f79cb26fba
>> --- /dev/null
>> +++ b/drivers/vdpa/virtio_pci/vp_vdpa.c
>> @@ -0,0 +1,456 @@
>> +// 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>
>> +#include <linux/virtio_pci_modern.h>
>> +
>> +#define VP_VDPA_QUEUE_MAX 256
>> +#define VP_VDPA_DRIVER_NAME "vp_vdpa"
>> +#define VP_VDPA_NAME_SIZE 256
>> +
>> +struct vp_vring {
>> +    void __iomem *notify;
>> +    char msix_name[VP_VDPA_NAME_SIZE];
>> +    struct vdpa_callback cb;
>> +    int irq;
>> +};
>> +
>> +struct vp_vdpa {
>> +    struct vdpa_device vdpa;
>> +    struct virtio_pci_modern_device mdev;
>> +    struct vp_vring *vring;
>> +    struct vdpa_callback config_cb;
>> +    char msix_name[VP_VDPA_NAME_SIZE];
>> +    int config_irq;
>> +    int queues;
>> +    int vectors;
>> +};
>> +
>> +static struct vp_vdpa *vdpa_to_vp(struct vdpa_device *vdpa)
>> +{
>> +    return container_of(vdpa, struct vp_vdpa, vdpa);
>> +}
>> +
>> +static struct virtio_pci_modern_device *vdpa_to_mdev(struct 
>> vdpa_device *vdpa)
>> +{
>> +    struct vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa);
>> +
>> +    return &vp_vdpa->mdev;
>> +}
>> +
>> +static u64 vp_vdpa_get_features(struct vdpa_device *vdpa)
>> +{
>> +    struct virtio_pci_modern_device *mdev = vdpa_to_mdev(vdpa);
>> +
>> +    return vp_modern_get_features(mdev);
>> +}
>> +
>> +static int vp_vdpa_set_features(struct vdpa_device *vdpa, u64 features)
>> +{
>> +    struct virtio_pci_modern_device *mdev = vdpa_to_mdev(vdpa);
>> +
>> +    vp_modern_set_features(mdev, features);
>> +
>> +    return 0;
>> +}
>> +
>> +static u8 vp_vdpa_get_status(struct vdpa_device *vdpa)
>> +{
>> +    struct virtio_pci_modern_device *mdev = vdpa_to_mdev(vdpa);
>> +
>> +    return vp_modern_get_status(mdev);
>> +}
>> +
>> +static void vp_vdpa_free_irq(struct vp_vdpa *vp_vdpa)
>> +{
>> +    struct virtio_pci_modern_device *mdev = &vp_vdpa->mdev;
>> +    struct pci_dev *pdev = mdev->pci_dev;
>> +    int i;
>> +
>> +    for (i = 0; i < vp_vdpa->queues; i++) {
>> +        if (vp_vdpa->vring[i].irq != VIRTIO_MSI_NO_VECTOR) {
>> +            vp_modern_queue_vector(mdev, i, VIRTIO_MSI_NO_VECTOR);
>> +            devm_free_irq(&pdev->dev, vp_vdpa->vring[i].irq,
>> +                      &vp_vdpa->vring[i]);
>> +            vp_vdpa->vring[i].irq = VIRTIO_MSI_NO_VECTOR;
>> +        }
>> +    }
>> +
>> +    if (vp_vdpa->config_irq != VIRTIO_MSI_NO_VECTOR) {
>> +        vp_modern_config_vector(mdev, VIRTIO_MSI_NO_VECTOR);
>> +        devm_free_irq(&pdev->dev, vp_vdpa->config_irq, vp_vdpa);
>> +        vp_vdpa->config_irq = VIRTIO_MSI_NO_VECTOR;
>> +    }
>> +
>> +    if (vp_vdpa->vectors) {
>> +        pci_free_irq_vectors(pdev);
>> +        vp_vdpa->vectors = 0;
>> +    }
>> +}
>> +
>> +static irqreturn_t vp_vdpa_vq_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 irqreturn_t vp_vdpa_config_handler(int irq, void *arg)
>> +{
>> +    struct vp_vdpa *vp_vdpa = arg;
>> +
>> +    if (vp_vdpa->config_cb.callback)
>> +        return vp_vdpa->config_cb.callback(vp_vdpa->config_cb.private);
>> +
>> +    return IRQ_HANDLED;
>> +}
>> +
>> +static int vp_vdpa_request_irq(struct vp_vdpa *vp_vdpa)
>> +{
>> +    struct virtio_pci_modern_device *mdev = &vp_vdpa->mdev;
>> +    struct pci_dev *pdev = mdev->pci_dev;
>> +    int i, ret, irq;
>> +    int queues = vp_vdpa->queues;
>> +    int vectors = queues + 1;
>> +
>> +    ret = pci_alloc_irq_vectors(pdev, vectors, vectors, PCI_IRQ_MSIX);
>> +    if (ret != vectors) {
>> +        dev_err(&pdev->dev,
>> +            "vp_vdpa: fail to allocate irq vectors want %d but %d\n",
>> +            vectors, ret);
>> +        return ret;
>> +    }
>> +
>> +    vp_vdpa->vectors = vectors;
>> +
>> +    for (i = 0; i < queues; i++) {
>> +        snprintf(vp_vdpa->vring[i].msix_name, VP_VDPA_NAME_SIZE,
>> +            "vp-vdpa[%s]-%d\n", pci_name(pdev), i);
>> +        irq = pci_irq_vector(pdev, i);
>> +        ret = devm_request_irq(&pdev->dev, irq,
>> +                       vp_vdpa_vq_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_modern_queue_vector(mdev, i, i);
>> +        vp_vdpa->vring[i].irq = irq;
>> +    }
>> +
>> +    snprintf(vp_vdpa->msix_name, VP_VDPA_NAME_SIZE, 
>> "vp-vdpa[%s]-config\n",
>> +         pci_name(pdev));
>> +    irq = pci_irq_vector(pdev, queues);
>> +    ret = devm_request_irq(&pdev->dev, irq, vp_vdpa_config_handler, 0,
>> +                   vp_vdpa->msix_name, vp_vdpa);
>> +    if (ret) {
>> +        dev_err(&pdev->dev,
>> +            "vp_vdpa: fail to request irq for vq %d\n", i);
>> +            goto err;
>> +    }
>> +    vp_modern_config_vector(mdev, queues);
>> +    vp_vdpa->config_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);
>> +    struct virtio_pci_modern_device *mdev = &vp_vdpa->mdev;
>> +    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_modern_set_status(mdev, 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)
>> +{
>> +    return VP_VDPA_QUEUE_MAX;
>> +}
>> +
>> +static int vp_vdpa_get_vq_state(struct vdpa_device *vdpa, u16 qid,
>> +                struct vdpa_vq_state *state)
>> +{
>> +    /* Note that this is not supported by virtio specification, so
>> +     * we return -EOPNOTSUPP here. This means we can't support live
>> +     * migration, vhost device start/stop.
>> +     */
>> +    return -EOPNOTSUPP;
>> +}
>> +
>> +static int vp_vdpa_set_vq_state(struct vdpa_device *vdpa, u16 qid,
>> +                const struct vdpa_vq_state *state)
>> +{
>> +    /* Note that this is not supported by virtio specification, so
>> +     * we return -ENOPOTSUPP here. This means we can't support live
>> +     * migration, vhost device start/stop.
>> +     */
>> +    return -EOPNOTSUPP;
>> +}
>> +
>> +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 virtio_pci_modern_device *mdev = vdpa_to_mdev(vdpa);
>> +
>> +    vp_modern_set_queue_enable(mdev, qid, ready);
>> +}
>> +
>> +static bool vp_vdpa_get_vq_ready(struct vdpa_device *vdpa, u16 qid)
>> +{
>> +    struct virtio_pci_modern_device *mdev = vdpa_to_mdev(vdpa);
>> +
>> +    return vp_modern_get_queue_enable(mdev, qid);
>> +}
>> +
>> +static void vp_vdpa_set_vq_num(struct vdpa_device *vdpa, u16 qid,
>> +                   u32 num)
>> +{
>> +    struct virtio_pci_modern_device *mdev = vdpa_to_mdev(vdpa);
>> +
>> +    vp_modern_set_queue_size(mdev, qid, num);
>> +}
>> +
>> +static int vp_vdpa_set_vq_address(struct vdpa_device *vdpa, u16 qid,
>> +                  u64 desc_area, u64 driver_area,
>> +                  u64 device_area)
>> +{
>> +    struct virtio_pci_modern_device *mdev = vdpa_to_mdev(vdpa);
>> +
>> +    vp_modern_queue_address(mdev, qid, desc_area,
>> +                driver_area, device_area);
>> +
>> +    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 virtio_pci_modern_device *mdev = vdpa_to_mdev(vdpa);
>> +
>> +    return vp_modern_generation(mdev);
>> +}
>> +
>> +static u32 vp_vdpa_get_device_id(struct vdpa_device *vdpa)
>> +{
>> +    struct virtio_pci_modern_device *mdev = vdpa_to_mdev(vdpa);
>> +
>> +    return mdev->id.device;
>> +}
>> +
>> +static u32 vp_vdpa_get_vendor_id(struct vdpa_device *vdpa)
>> +{
>> +    struct virtio_pci_modern_device *mdev = vdpa_to_mdev(vdpa);
>> +
>> +    return mdev->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);
>> +    struct virtio_pci_modern_device *mdev = &vp_vdpa->mdev;
>> +    u8 old, new;
>> +    u8 *p;
>> +    int i;
>> +
>> +    do {
>> +        old = vp_ioread8(&mdev->common->config_generation);
>> +        p = buf;
>> +        for (i = 0; i < len; i++)
>> +            *p++ = vp_ioread8(mdev->device + offset + i);
>> +
>> +        new = vp_ioread8(&mdev->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);
>> +    struct virtio_pci_modern_device *mdev = &vp_vdpa->mdev;
>> +    const u8 *p = buf;
>> +    int i;
>> +
>> +    for (i = 0; i < len; i++)
>> +        vp_iowrite8(*p++, mdev->device + offset + i);
>> +}
>> +
>> +static void vp_vdpa_set_config_cb(struct vdpa_device *vdpa,
>> +                  struct vdpa_callback *cb)
>> +{
>> +    struct vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa);
>> +
>> +    vp_vdpa->config_cb = *cb;
>> +}
>> +
>> +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 void vp_vdpa_free_irq_vectors(void *data)
>> +{
>> +    pci_free_irq_vectors(data);
>> +}
>> +
>> +static int vp_vdpa_probe(struct pci_dev *pdev, const struct 
>> pci_device_id *id)
>> +{
>> +    struct virtio_pci_modern_device *mdev;
>> +    struct device *dev = &pdev->dev;
>> +    struct vp_vdpa *vp_vdpa;
>> +    u16 notify_off;
>> +    int ret, i;
>> +
>> +    ret = pcim_enable_device(pdev);
>> +    if (ret)
>> +        return ret;
>> +
>> +    vp_vdpa = vdpa_alloc_device(struct vp_vdpa, vdpa,
>> +                    dev, &vp_vdpa_ops, NULL);
>> +    if (vp_vdpa == NULL) {
>> +        dev_err(dev, "vp_vdpa: Failed to allocate vDPA structure\n");
>> +        return -ENOMEM;
>> +    }
>> +
>> +    mdev = &vp_vdpa->mdev;
>> +    mdev->pci_dev = pdev;
>> +
>> +    if (vp_modern_probe(mdev)) {
>> +        dev_err(&pdev->dev, "Failed to probe modern PCI device\n");
>
> Should we set 'ret' with an error value?
> Maybe we can reuse the return value of vp_modern_probe().


Right, will fix.


>
>> +        goto err;
>> +    }
>> +
>> +    pci_set_master(pdev);
>> +    pci_set_drvdata(pdev, vp_vdpa);
>> +
>> +    vp_vdpa->vdpa.dma_dev = &pdev->dev;
>> +    vp_vdpa->queues = vp_modern_get_num_queues(mdev);
>> +
>> +    ret = devm_add_action_or_reset(dev, vp_vdpa_free_irq_vectors, 
>> pdev);
>> +    if (ret) {
>> +        dev_err(&pdev->dev,
>> +            "Failed for adding devres for freeing irq vectors\n");
>> +        goto err;
>> +    }
>> +
>> +    vp_vdpa->vring = devm_kcalloc(&pdev->dev, vp_vdpa->queues,
>> +                      sizeof(*vp_vdpa->vring),
>> +                      GFP_KERNEL);
>> +    if (!vp_vdpa->vring) {
>> +        dev_err(&pdev->dev, "Fail to allocate virtqueues\n");
>
> Ditto, but in this case maybe we can set -ENOMEM.


Will fix this as well.

Thanks


>
>> +        goto err;
>> +    }
>> +
>> +    for (i = 0; i < vp_vdpa->queues; i++) {
>> +        notify_off = vp_modern_get_queue_notify_off(mdev, i);
>> +        vp_vdpa->vring[i].irq = VIRTIO_MSI_NO_VECTOR;
>> +        vp_vdpa->vring[i].notify = mdev->notify_base +
>> +            notify_off * mdev->notify_offset_multiplier;
>> +    }
>> +    vp_vdpa->config_irq = VIRTIO_MSI_NO_VECTOR;
>> +
>> +    ret = vdpa_register_device(&vp_vdpa->vdpa, vp_vdpa->queues);
>> +    if (ret) {
>> +        dev_err(&pdev->dev, "Failed to register to vdpa bus\n");
>> +        goto err;
>> +    }
>> +
>> +    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);
>> +    vp_modern_remove(&vp_vdpa->mdev);
>> +}
>> +
>> +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");
>> -- 
>> 2.25.1
>>
>
>
> Thanks,
> Stefano
>

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