Re: [RFC 2/2] vhost: IFC VF vdpa layer

["Zhu, Lingshan" <lingshan.zhu@intel.com>]

Hello Jason,

Thanks for your comments, I am on a conference travel, I will reply next 
Monday.

Thanks,
BR
Zhu Lingshan
On 10/16/2019 6:19 PM, Jason Wang wrote:
>
> On 2019/10/16 上午9:30, Zhu Lingshan wrote:
>> This commit introduced IFC VF operations for vdpa, which complys to
>> vhost_mdev interfaces, handles IFC VF initialization,
>> configuration and removal.
>>
>> Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com>
>> ---
>>   drivers/vhost/ifcvf/ifcvf_main.c | 541 
>> +++++++++++++++++++++++++++++++++++++++
>>   1 file changed, 541 insertions(+)
>>   create mode 100644 drivers/vhost/ifcvf/ifcvf_main.c
>>
>> diff --git a/drivers/vhost/ifcvf/ifcvf_main.c 
>> b/drivers/vhost/ifcvf/ifcvf_main.c
>> new file mode 100644
>> index 000000000000..c48a29969a85
>> --- /dev/null
>> +++ b/drivers/vhost/ifcvf/ifcvf_main.c
>> @@ -0,0 +1,541 @@
>> +// SPDX-License-Identifier: GPL-2.0-only
>> +/*
>> + * Copyright (C) 2019 Intel Corporation.
>> + */
>> +
>> +#include <linux/interrupt.h>
>> +#include <linux/module.h>
>> +#include <linux/mdev.h>
>> +#include <linux/pci.h>
>> +#include <linux/sysfs.h>
>> +
>> +#include "ifcvf_base.h"
>> +
>> +#define VERSION_STRING    "0.1"
>> +#define DRIVER_AUTHOR    "Intel Corporation"
>> +#define IFCVF_DRIVER_NAME    "ifcvf"
>> +
>> +static irqreturn_t ifcvf_intr_handler(int irq, void *arg)
>> +{
>> +    struct vring_info *vring = arg;
>> +
>> +    if (vring->cb.callback)
>> +        return vring->cb.callback(vring->cb.private);
>> +
>> +    return IRQ_HANDLED;
>> +}
>> +
>> +static u64 ifcvf_mdev_get_features(struct mdev_device *mdev)
>> +{
>> +    return IFC_SUPPORTED_FEATURES;
>
>
> I would expect this should be done by querying the hw. Or IFC VF can't 
> get any update through its firmware?
>
>
>> +}
>> +
>> +static int ifcvf_mdev_set_features(struct mdev_device *mdev, u64 
>> features)
>> +{
>> +    struct ifcvf_adapter *adapter = mdev_get_drvdata(mdev);
>> +    struct ifcvf_hw *vf = IFC_PRIVATE_TO_VF(adapter);
>> +
>> +    vf->req_features = features;
>> +
>> +    return 0;
>> +}
>> +
>> +static u64 ifcvf_mdev_get_vq_state(struct mdev_device *mdev, u16 qid)
>> +{
>> +    struct ifcvf_adapter *adapter = mdev_get_drvdata(mdev);
>> +    struct ifcvf_hw *vf = IFC_PRIVATE_TO_VF(adapter);
>> +
>> +    return vf->vring[qid].last_avail_idx;
>
>
> Does this really work? I'd expect it should be fetched from hw since 
> it's an internal state.
>
>
>> +}
>> +
>> +static int ifcvf_mdev_set_vq_state(struct mdev_device *mdev, u16 
>> qid, u64 num)
>> +{
>> +    struct ifcvf_adapter *adapter = mdev_get_drvdata(mdev);
>> +    struct ifcvf_hw *vf = IFC_PRIVATE_TO_VF(adapter);
>> +
>> +    vf->vring[qid].last_used_idx = num;
>
>
> I fail to understand why last_used_idx is needed. It looks to me the 
> used idx in the used ring is sufficient.
>
>
>> +    vf->vring[qid].last_avail_idx = num;
>
>
> Do we need a synchronization with hw immediately here?
>
>
>> +
>> +    return 0;
>> +}
>> +
>> +static int ifcvf_mdev_set_vq_address(struct mdev_device *mdev, u16 idx,
>> +                     u64 desc_area, u64 driver_area,
>> +                     u64 device_area)
>> +{
>> +    struct ifcvf_adapter *adapter = mdev_get_drvdata(mdev);
>> +    struct ifcvf_hw *vf = IFC_PRIVATE_TO_VF(adapter);
>> +
>> +    vf->vring[idx].desc = desc_area;
>> +    vf->vring[idx].avail = driver_area;
>> +    vf->vring[idx].used = device_area;
>> +
>> +    return 0;
>> +}
>> +
>> +static void ifcvf_mdev_set_vq_num(struct mdev_device *mdev, u16 qid, 
>> u32 num)
>> +{
>> +    struct ifcvf_adapter *adapter = mdev_get_drvdata(mdev);
>> +    struct ifcvf_hw *vf = IFC_PRIVATE_TO_VF(adapter);
>> +
>> +    vf->vring[qid].size = num;
>> +}
>> +
>> +static void ifcvf_mdev_set_vq_ready(struct mdev_device *mdev,
>> +                u16 qid, bool ready)
>> +{
>> +
>> +    struct ifcvf_adapter *adapter = mdev_get_drvdata(mdev);
>> +    struct ifcvf_hw *vf = IFC_PRIVATE_TO_VF(adapter);
>> +
>> +    vf->vring[qid].ready = ready;
>> +}
>> +
>> +static bool ifcvf_mdev_get_vq_ready(struct mdev_device *mdev, u16 qid)
>> +{
>> +
>> +    struct ifcvf_adapter *adapter = mdev_get_drvdata(mdev);
>> +    struct ifcvf_hw *vf = IFC_PRIVATE_TO_VF(adapter);
>> +
>> +    return vf->vring[qid].ready;
>> +}
>> +
>> +static void ifcvf_mdev_set_vq_cb(struct mdev_device *mdev, u16 idx,
>> +                 struct virtio_mdev_callback *cb)
>> +{
>> +    struct ifcvf_adapter *adapter = mdev_get_drvdata(mdev);
>> +    struct ifcvf_hw *vf = IFC_PRIVATE_TO_VF(adapter);
>> +
>> +    vf->vring[idx].cb = *cb;
>> +}
>> +
>> +static void ifcvf_mdev_kick_vq(struct mdev_device *mdev, u16 idx)
>> +{
>> +    struct ifcvf_adapter *adapter = mdev_get_drvdata(mdev);
>> +    struct ifcvf_hw *vf = IFC_PRIVATE_TO_VF(adapter);
>> +
>> +    ifcvf_notify_queue(vf, idx);
>> +}
>> +
>> +static u8 ifcvf_mdev_get_status(struct mdev_device *mdev)
>> +{
>> +    struct ifcvf_adapter *adapter = mdev_get_drvdata(mdev);
>> +    struct ifcvf_hw *vf = IFC_PRIVATE_TO_VF(adapter);
>> +
>> +    return vf->status;
>> +}
>> +
>> +static u32 ifcvf_mdev_get_generation(struct mdev_device *mdev)
>> +{
>> +    struct ifcvf_adapter *adapter = mdev_get_drvdata(mdev);
>> +    struct ifcvf_hw *vf = IFC_PRIVATE_TO_VF(adapter);
>> +
>> +    return vf->generation;
>> +}
>> +
>> +static int ifcvf_mdev_get_version(struct mdev_device *mdev)
>> +{
>> +    return VIRTIO_MDEV_VERSION;
>> +}
>> +
>> +static u32 ifcvf_mdev_get_device_id(struct mdev_device *mdev)
>> +{
>> +    return IFCVF_DEVICE_ID;
>> +}
>> +
>> +static u32 ifcvf_mdev_get_vendor_id(struct mdev_device *mdev)
>> +{
>> +    return IFCVF_VENDOR_ID;
>> +}
>> +
>> +static u16 ifcvf_mdev_get_vq_align(struct mdev_device *mdev)
>> +{
>> +    return IFCVF_QUEUE_ALIGNMENT;
>> +}
>> +
>> +static int ifcvf_start_datapath(void *private)
>> +{
>> +    int i, ret;
>> +    struct ifcvf_hw *vf = IFC_PRIVATE_TO_VF(private);
>> +
>> +    for (i = 0; i < (IFCVF_MAX_QUEUE_PAIRS * 2); i++) {
>> +        if (!vf->vring[i].ready)
>> +            break;
>
>
> Looks like error should be returned here?
>
>
>> +
>> +        if (!vf->vring[i].size)
>> +            break;
>> +
>> +        if (!vf->vring[i].desc || !vf->vring[i].avail ||
>> +            !vf->vring[i].used)
>> +            break;
>> +    }
>> +    vf->nr_vring = i;
>> +
>> +    ret = ifcvf_start_hw(vf);
>> +    return ret;
>> +}
>> +
>> +static int ifcvf_stop_datapath(void *private)
>> +{
>> +    struct ifcvf_hw *vf = IFC_PRIVATE_TO_VF(private);
>> +    int i;
>> +
>> +    for (i = 0; i < IFCVF_MAX_QUEUES; i++)
>> +        vf->vring[i].cb.callback = NULL;
>
>
> Any synchronization is needed for the vq irq handler?
>
>
>> +
>> +    ifcvf_stop_hw(vf);
>> +
>> +    return 0;
>> +}
>> +
>> +static void ifcvf_reset_vring(struct ifcvf_adapter *adapter)
>> +{
>> +    int i;
>> +    struct ifcvf_hw *vf = IFC_PRIVATE_TO_VF(adapter);
>> +
>> +    for (i = 0; i < IFCVF_MAX_QUEUE_PAIRS * 2; i++) {
>> +        vf->vring[i].last_used_idx = 0;
>> +        vf->vring[i].last_avail_idx = 0;
>> +        vf->vring[i].desc = 0;
>> +        vf->vring[i].avail = 0;
>> +        vf->vring[i].used = 0;
>> +        vf->vring[i].ready = 0;
>> +        vf->vring->cb.callback = NULL;
>> +        vf->vring->cb.private = NULL;
>> +    }
>> +}
>> +
>> +static void ifcvf_mdev_set_status(struct mdev_device *mdev, u8 status)
>> +{
>> +    struct ifcvf_adapter *adapter = mdev_get_drvdata(mdev);
>> +    struct ifcvf_hw *vf = IFC_PRIVATE_TO_VF(adapter);
>> +
>> +    vf->status = status;
>> +
>> +    if (status == 0) {
>> +        ifcvf_stop_datapath(adapter);
>> +        ifcvf_reset_vring(adapter);
>> +        return;
>> +    }
>> +
>> +    if (status & VIRTIO_CONFIG_S_DRIVER_OK) {
>> +        ifcvf_start_datapath(adapter);
>> +        return;
>> +    }
>> +}
>> +
>> +static u16 ifcvf_mdev_get_queue_max(struct mdev_device *mdev)
>> +{
>> +    return IFCVF_MAX_QUEUES;
>
>
> The name is confusing, it was used to return the maximum queue size. 
> In new version of virtio-mdev, the callback was renamed as 
> get_vq_num_max().
>
>
>> +}
>> +
>> +static struct virtio_mdev_device_ops ifc_mdev_ops = {
>> +    .get_features  = ifcvf_mdev_get_features,
>> +    .set_features  = ifcvf_mdev_set_features,
>> +    .get_status    = ifcvf_mdev_get_status,
>> +    .set_status    = ifcvf_mdev_set_status,
>> +    .get_queue_max = ifcvf_mdev_get_queue_max,
>> +    .get_vq_state   = ifcvf_mdev_get_vq_state,
>> +    .set_vq_state   = ifcvf_mdev_set_vq_state,
>> +    .set_vq_cb      = ifcvf_mdev_set_vq_cb,
>> +    .set_vq_ready   = ifcvf_mdev_set_vq_ready,
>> +    .get_vq_ready    = ifcvf_mdev_get_vq_ready,
>> +    .set_vq_num     = ifcvf_mdev_set_vq_num,
>> +    .set_vq_address = ifcvf_mdev_set_vq_address,
>> +    .kick_vq        = ifcvf_mdev_kick_vq,
>> +    .get_generation    = ifcvf_mdev_get_generation,
>> +    .get_version    = ifcvf_mdev_get_version,
>> +    .get_device_id    = ifcvf_mdev_get_device_id,
>> +    .get_vendor_id    = ifcvf_mdev_get_vendor_id,
>> +    .get_vq_align    = ifcvf_mdev_get_vq_align,
>> +};
>
>
> set_config/get_config is missing. It looks to me they are not hard, 
> just implementing the access to dev_cfg. It's key to make kernel 
> virtio driver to work.
>
> And in the new version of virito-mdev, features like _F_LOG_ALL should 
> be advertised through get_mdev_features.
>
>
>> +
>> +static int ifcvf_init_msix(struct ifcvf_adapter *adapter)
>> +{
>> +    int vector, i, ret, irq;
>> +    struct pci_dev *pdev = to_pci_dev(adapter->dev);
>> +    struct ifcvf_hw *vf = &adapter->vf;
>> +
>> +    ret = pci_alloc_irq_vectors(pdev, IFCVF_MAX_INTR,
>> +            IFCVF_MAX_INTR, PCI_IRQ_MSIX);
>> +    if (ret < 0) {
>> +        IFC_ERR(adapter->dev, "Failed to alloc irq vectors.\n");
>> +        return ret;
>> +    }
>> +
>> +    for (i = 0; i < IFCVF_MAX_QUEUE_PAIRS * 2; i++) {
>> +        vector = i + IFCVF_MSI_QUEUE_OFF;
>> +        irq = pci_irq_vector(pdev, vector);
>> +        ret = request_irq(irq, ifcvf_intr_handler, 0,
>> +                pci_name(pdev), &vf->vring[i]);
>> +        if (ret) {
>> +            IFC_ERR(adapter->dev,
>> +                "Failed to request irq for vq %d.\n", i);
>> +            return ret;
>> +        }
>> +    }
>
>
> Do we need to provide fallback when we can't do per vq MSIX?
>
>
>> +
>> +    return 0;
>> +}
>> +
>> +static void ifcvf_destroy_adapter(struct ifcvf_adapter *adapter)
>> +{
>> +    int i, vector, irq;
>> +    struct ifcvf_hw *vf = IFC_PRIVATE_TO_VF(adapter);
>> +    struct pci_dev *pdev = to_pci_dev(adapter->dev);
>> +
>> +    for (i = 0; i < IFCVF_MAX_QUEUE_PAIRS * 2; i++) {
>> +        vector = i + IFCVF_MSI_QUEUE_OFF;
>> +        irq = pci_irq_vector(pdev, vector);
>> +        free_irq(irq, &vf->vring[i]);
>> +    }
>> +}
>> +
>> +static ssize_t name_show(struct kobject *kobj, struct device *dev, 
>> char *buf)
>> +{
>> +    const char *name = "vhost accelerator (virtio ring compatible)";
>> +
>> +    return sprintf(buf, "%s\n", name);
>> +}
>> +MDEV_TYPE_ATTR_RO(name);
>> +
>> +static ssize_t device_api_show(struct kobject *kobj, struct device 
>> *dev,
>> +                   char *buf)
>> +{
>> +    return sprintf(buf, "%s\n", VIRTIO_MDEV_DEVICE_API_STRING);
>> +}
>> +MDEV_TYPE_ATTR_RO(device_api);
>> +
>> +static ssize_t available_instances_show(struct kobject *kobj,
>> +                    struct device *dev, char *buf)
>> +{
>> +    struct pci_dev *pdev = to_pci_dev(dev);
>> +    struct ifcvf_adapter *adapter = pci_get_drvdata(pdev);
>> +
>> +    return sprintf(buf, "%d\n", adapter->mdev_count);
>> +}
>> +
>> +MDEV_TYPE_ATTR_RO(available_instances);
>> +
>> +static ssize_t type_show(struct kobject *kobj,
>> +            struct device *dev, char *buf)
>> +{
>> +    return sprintf(buf, "%s\n", "net");
>> +}
>> +
>> +MDEV_TYPE_ATTR_RO(type);
>> +
>> +
>> +static struct attribute *mdev_types_attrs[] = {
>> +    &mdev_type_attr_name.attr,
>> +    &mdev_type_attr_device_api.attr,
>> +    &mdev_type_attr_available_instances.attr,
>> +    &mdev_type_attr_type.attr,
>> +    NULL,
>> +};
>> +
>> +static struct attribute_group mdev_type_group = {
>> +    .name  = "vdpa_virtio",
>
>
> To be consistent, it should be "vhost" or "virtio".
>
>
>> +    .attrs = mdev_types_attrs,
>> +};
>> +
>> +static struct attribute_group *mdev_type_groups[] = {
>> +    &mdev_type_group,
>> +    NULL,
>> +};
>> +
>> +const struct attribute_group *mdev_dev_groups[] = {
>> +    NULL,
>> +};
>> +
>> +static int ifcvf_mdev_create(struct kobject *kobj, struct 
>> mdev_device *mdev)
>> +{
>> +    struct device *dev = mdev_parent_dev(mdev);
>> +    struct pci_dev *pdev = to_pci_dev(dev);
>> +    struct ifcvf_adapter *adapter = pci_get_drvdata(pdev);
>> +    int ret = 0;
>> +
>> +    mutex_lock(&adapter->mdev_lock);
>> +
>> +    if (adapter->mdev_count < 1) {
>> +        ret = -EINVAL;
>> +        goto out;
>> +    }
>> +
>> +    mdev_set_class_id(mdev, MDEV_ID_VHOST);
>> +    mdev_set_dev_ops(mdev, &ifc_mdev_ops);
>> +
>> +    mdev_set_drvdata(mdev, adapter);
>> +    mdev_set_iommu_device(mdev_dev(mdev), dev);
>> +
>> +    INIT_LIST_HEAD(&adapter->dma_maps);
>> +    adapter->mdev_count--;
>> +
>> +out:
>> +    mutex_unlock(&adapter->mdev_lock);
>> +    return ret;
>> +}
>> +
>> +static int ifcvf_mdev_remove(struct mdev_device *mdev)
>> +{
>> +    struct device *dev = mdev_parent_dev(mdev);
>> +    struct pci_dev *pdev = to_pci_dev(dev);
>> +    struct ifcvf_adapter *adapter = pci_get_drvdata(pdev);
>> +
>> +    mutex_lock(&adapter->mdev_lock);
>> +    adapter->mdev_count++;
>> +    mutex_unlock(&adapter->mdev_lock);
>> +
>> +    return 0;
>> +}
>> +
>> +static struct mdev_parent_ops ifcvf_mdev_fops = {
>> +    .owner            = THIS_MODULE,
>> +    .supported_type_groups    = mdev_type_groups,
>> +    .mdev_attr_groups    = mdev_dev_groups,
>> +    .create            = ifcvf_mdev_create,
>> +    .remove            = ifcvf_mdev_remove,
>> +};
>> +
>> +static int ifcvf_probe(struct pci_dev *pdev, const struct 
>> pci_device_id *id)
>> +{
>> +    struct device *dev = &pdev->dev;
>> +    struct ifcvf_adapter *adapter;
>> +    struct ifcvf_hw *vf;
>> +    int ret, i;
>> +
>> +    adapter = kzalloc(sizeof(struct ifcvf_adapter), GFP_KERNEL);
>> +    if (adapter == NULL) {
>> +        ret = -ENOMEM;
>> +        goto fail;
>> +    }
>> +
>> +    mutex_init(&adapter->mdev_lock);
>> +    adapter->mdev_count = 1;
>
>
> So this is per VF based vDPA implementation, which seems not 
> convenient for management.  Anyhow we can control the creation in PF?
>
> Thanks
>
>
>> +    adapter->dev = dev;
>> +
>> +    pci_set_drvdata(pdev, adapter);
>> +
>> +    ret = pci_enable_device(pdev);
>> +    if (ret) {
>> +        IFC_ERR(adapter->dev, "Failed to enable device.\n");
>> +        goto free_adapter;
>> +    }
>> +
>> +    ret = pci_request_regions(pdev, IFCVF_DRIVER_NAME);
>> +    if (ret) {
>> +        IFC_ERR(adapter->dev, "Failed to request MMIO region.\n");
>> +        goto disable_device;
>> +    }
>> +
>> +    pci_set_master(pdev);
>> +
>> +    ret = ifcvf_init_msix(adapter);
>> +    if (ret) {
>> +        IFC_ERR(adapter->dev, "Failed to initialize MSIX.\n");
>> +        goto free_msix;
>> +    }
>> +
>> +    vf = &adapter->vf;
>> +    for (i = 0; i < IFCVF_PCI_MAX_RESOURCE; i++) {
>> +        vf->mem_resource[i].phys_addr = pci_resource_start(pdev, i);
>> +        vf->mem_resource[i].len = pci_resource_len(pdev, i);
>> +        if (!vf->mem_resource[i].len) {
>> +            vf->mem_resource[i].addr = NULL;
>> +            continue;
>> +        }
>> +
>> +        vf->mem_resource[i].addr = pci_iomap_range(pdev, i, 0,
>> +                vf->mem_resource[i].len);
>> +        if (!vf->mem_resource[i].addr) {
>> +            IFC_ERR(adapter->dev, "Failed to map IO resource %d\n",
>> +                i);
>> +            return -1;
>> +        }
>> +    }
>> +
>> +    if (ifcvf_init_hw(vf, pdev) < 0)
>> +        return -1;
>> +
>> +    ret = mdev_register_device(dev, &ifcvf_mdev_fops);
>> +    if (ret) {
>> +        IFC_ERR(adapter->dev,  "Failed to register mdev device\n");
>> +        goto destroy_adapter;
>> +    }
>> +
>> +    return 0;
>> +
>> +destroy_adapter:
>> +    ifcvf_destroy_adapter(adapter);
>> +free_msix:
>> +    pci_free_irq_vectors(pdev);
>> +    pci_release_regions(pdev);
>> +disable_device:
>> +    pci_disable_device(pdev);
>> +free_adapter:
>> +    kfree(adapter);
>> +fail:
>> +    return ret;
>> +}
>> +
>> +static void ifcvf_remove(struct pci_dev *pdev)
>> +{
>> +    struct device *dev = &pdev->dev;
>> +    struct ifcvf_adapter *adapter = pci_get_drvdata(pdev);
>> +    struct ifcvf_hw *vf;
>> +    int i;
>> +
>> +    mdev_unregister_device(dev);
>> +
>> +    vf = &adapter->vf;
>> +    for (i = 0; i < IFCVF_PCI_MAX_RESOURCE; i++) {
>> +        if (vf->mem_resource[i].addr) {
>> +            pci_iounmap(pdev, vf->mem_resource[i].addr);
>> +            vf->mem_resource[i].addr = NULL;
>> +        }
>> +    }
>> +
>> +    ifcvf_destroy_adapter(adapter);
>> +    pci_free_irq_vectors(pdev);
>> +
>> +    pci_release_regions(pdev);
>> +    pci_disable_device(pdev);
>> +
>> +    kfree(adapter);
>> +}
>> +
>> +static struct pci_device_id ifcvf_pci_ids[] = {
>> +    { PCI_DEVICE_SUB(IFCVF_VENDOR_ID,
>> +            IFCVF_DEVICE_ID,
>> +            IFCVF_SUBSYS_VENDOR_ID,
>> +            IFCVF_SUBSYS_DEVICE_ID) },
>> +    { 0 },
>> +};
>> +MODULE_DEVICE_TABLE(pci, ifcvf_pci_ids);
>> +
>> +static struct pci_driver ifcvf_driver = {
>> +    .name     = IFCVF_DRIVER_NAME,
>> +    .id_table = ifcvf_pci_ids,
>> +    .probe    = ifcvf_probe,
>> +    .remove   = ifcvf_remove,
>> +};
>> +
>> +static int __init ifcvf_init_module(void)
>> +{
>> +    int ret;
>> +
>> +    ret = pci_register_driver(&ifcvf_driver);
>> +    return ret;
>> +}
>> +
>> +static void __exit ifcvf_exit_module(void)
>> +{
>> +    pci_unregister_driver(&ifcvf_driver);
>> +}
>> +
>> +module_init(ifcvf_init_module);
>> +module_exit(ifcvf_exit_module);
>> +
>> +MODULE_LICENSE("GPL v2");
>> +MODULE_VERSION(VERSION_STRING);
>> +MODULE_AUTHOR(DRIVER_AUTHOR);