Re: [PATCH v2 10/13] samples: refine vfio-mdev-pci driver

[Alex Williamson]

On Thu,  5 Sep 2019 15:59:27 +0800
Liu Yi L <yi.l.liu@xxxxxxxxx> wrote:

> From: Alex Williamson <alex.williamson@xxxxxxxxxx>
> 
> This patch refines the implementation of original vfio-mdev-pci driver.
> 
> And the vfio-mdev-pci-type_name will be named per the following rule:
> 
> 	vmdev->attr.name = kasprintf(GFP_KERNEL,
> 				     "%04x:%04x:%04x:%04x:%06x:%02x",
> 				     pdev->vendor, pdev->device,
> 				     pdev->subsystem_vendor,
> 				     pdev->subsystem_device, pdev->class,
> 				     pdev->revision);
> 
> Before usage, check the /sys/bus/pci/devices/$bdf/mdev_supported_types/
> to ensure the final mdev_supported_types.
> 
> Cc: Kevin Tian <kevin.tian@xxxxxxxxx>
> Cc: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
> Signed-off-by: Alex Williamson <alex.williamson@xxxxxxxxxx>
> Signed-off-by: Liu Yi L <yi.l.liu@xxxxxxxxx>
> ---
>  drivers/vfio/pci/vfio_mdev_pci.c | 123 +++++++++++++++++++++++----------------
>  1 file changed, 72 insertions(+), 51 deletions(-)
> 
> diff --git a/drivers/vfio/pci/vfio_mdev_pci.c b/drivers/vfio/pci/vfio_mdev_pci.c
> index 07c8067..09143d3 100644
> --- a/drivers/vfio/pci/vfio_mdev_pci.c
> +++ b/drivers/vfio/pci/vfio_mdev_pci.c
> @@ -65,18 +65,22 @@ MODULE_PARM_DESC(disable_idle_d3,
>  
>  static struct pci_driver vfio_mdev_pci_driver;
>  
> -static ssize_t
> -name_show(struct kobject *kobj, struct device *dev, char *buf)
> -{
> -	return sprintf(buf, "%s-type1\n", dev_name(dev));
> -}
> -
> -MDEV_TYPE_ATTR_RO(name);
> +struct vfio_mdev_pci_device {
> +	struct vfio_pci_device vdev;
> +	struct mdev_parent_ops ops;
> +	struct attribute_group *groups[2];
> +	struct attribute_group attr;
> +	atomic_t avail;
> +};
>  
>  static ssize_t
>  available_instances_show(struct kobject *kobj, struct device *dev, char *buf)
>  {
> -	return sprintf(buf, "%d\n", 1);
> +	struct vfio_mdev_pci_device *vmdev;
> +
> +	vmdev = pci_get_drvdata(to_pci_dev(dev));
> +
> +	return sprintf(buf, "%d\n", atomic_read(&vmdev->avail));
>  }
>  
>  MDEV_TYPE_ATTR_RO(available_instances);
> @@ -90,62 +94,57 @@ static ssize_t device_api_show(struct kobject *kobj, struct device *dev,
>  MDEV_TYPE_ATTR_RO(device_api);
>  
>  static struct attribute *vfio_mdev_pci_types_attrs[] = {
> -	&mdev_type_attr_name.attr,
>  	&mdev_type_attr_device_api.attr,
>  	&mdev_type_attr_available_instances.attr,
>  	NULL,
>  };
>  
> -static struct attribute_group vfio_mdev_pci_type_group1 = {
> -	.name  = "type1",
> -	.attrs = vfio_mdev_pci_types_attrs,
> -};
> -
> -struct attribute_group *vfio_mdev_pci_type_groups[] = {
> -	&vfio_mdev_pci_type_group1,
> -	NULL,
> -};
> -
>  struct vfio_mdev_pci {
>  	struct vfio_pci_device *vdev;
>  	struct mdev_device *mdev;
> -	unsigned long handle;
>  };
>  
>  static int vfio_mdev_pci_create(struct kobject *kobj, struct mdev_device *mdev)
>  {
>  	struct device *pdev;
> -	struct vfio_pci_device *vdev;
> +	struct vfio_mdev_pci_device *vmdev;
>  	struct vfio_mdev_pci *pmdev;
>  	int ret;
>  
>  	pdev = mdev_parent_dev(mdev);
> -	vdev = dev_get_drvdata(pdev);
> +	vmdev = dev_get_drvdata(pdev);
> +
> +	if (atomic_dec_if_positive(&vmdev->avail) < 0)
> +		return -ENOSPC;
> +
>  	pmdev = kzalloc(sizeof(struct vfio_mdev_pci), GFP_KERNEL);
> -	if (pmdev == NULL) {
> -		ret = -EBUSY;
> -		goto out;
> -	}
> +	if (!pmdev)
> +		return -ENOMEM;

Needs an atomic_inc(&vmdev->avail) in this error path.  Thanks,

Alex

>  
>  	pmdev->mdev = mdev;
> -	pmdev->vdev = vdev;
> +	pmdev->vdev = &vmdev->vdev;
>  	mdev_set_drvdata(mdev, pmdev);
>  	ret = mdev_set_iommu_device(mdev_dev(mdev), pdev);
>  	if (ret) {
>  		pr_info("%s, failed to config iommu isolation for mdev: %s on pf: %s\n",
>  			__func__, dev_name(mdev_dev(mdev)), dev_name(pdev));
> -		goto out;
> +		kfree(pmdev);
> +		atomic_inc(&vmdev->avail);
> +		return ret;
>  	}
>  
> -out:
> -	return ret;
> +	return 0;
>  }
>  
>  static int vfio_mdev_pci_remove(struct mdev_device *mdev)
>  {
>  	struct vfio_mdev_pci *pmdev = mdev_get_drvdata(mdev);
> +	struct vfio_mdev_pci_device *vmdev;
> +
> +	vmdev = container_of(pmdev->vdev, struct vfio_mdev_pci_device, vdev);
>  
>  	kfree(pmdev);
> +	atomic_inc(&vmdev->avail);
>  	pr_info("%s, succeeded for mdev: %s\n", __func__,
>  		     dev_name(mdev_dev(mdev)));
>  
> @@ -237,24 +236,12 @@ static ssize_t vfio_mdev_pci_write(struct mdev_device *mdev,
>  	return vfio_pci_write(pmdev->vdev, (char __user *)buf, count, ppos);
>  }
>  
> -static const struct mdev_parent_ops vfio_mdev_pci_ops = {
> -	.supported_type_groups	= vfio_mdev_pci_type_groups,
> -	.create			= vfio_mdev_pci_create,
> -	.remove			= vfio_mdev_pci_remove,
> -
> -	.open			= vfio_mdev_pci_open,
> -	.release		= vfio_mdev_pci_release,
> -
> -	.read			= vfio_mdev_pci_read,
> -	.write			= vfio_mdev_pci_write,
> -	.mmap			= vfio_mdev_pci_mmap,
> -	.ioctl			= vfio_mdev_pci_ioctl,
> -};
> -
>  static int vfio_mdev_pci_driver_probe(struct pci_dev *pdev,
>  				       const struct pci_device_id *id)
>  {
> +	struct vfio_mdev_pci_device *vmdev;
>  	struct vfio_pci_device *vdev;
> +	const struct mdev_parent_ops *ops;
>  	int ret;
>  
>  	if (pdev->hdr_type != PCI_HEADER_TYPE_NORMAL)
> @@ -273,10 +260,38 @@ static int vfio_mdev_pci_driver_probe(struct pci_dev *pdev,
>  		return -EBUSY;
>  	}
>  
> -	vdev = kzalloc(sizeof(*vdev), GFP_KERNEL);
> -	if (!vdev)
> +	vmdev = kzalloc(sizeof(*vmdev), GFP_KERNEL);
> +	if (!vmdev)
>  		return -ENOMEM;
>  
> +	vmdev->attr.name = kasprintf(GFP_KERNEL,
> +				     "%04x:%04x:%04x:%04x:%06x:%02x",
> +				     pdev->vendor, pdev->device,
> +				     pdev->subsystem_vendor,
> +				     pdev->subsystem_device, pdev->class,
> +				     pdev->revision);
> +	if (!vmdev->attr.name) {
> +		kfree(vmdev);
> +		return -ENOMEM;
> +	}
> +
> +	atomic_set(&vmdev->avail, 1);
> +
> +	vmdev->attr.attrs = vfio_mdev_pci_types_attrs;
> +	vmdev->groups[0] = &vmdev->attr;
> +
> +	vmdev->ops.supported_type_groups = vmdev->groups;
> +	vmdev->ops.create = vfio_mdev_pci_create;
> +	vmdev->ops.remove = vfio_mdev_pci_remove;
> +	vmdev->ops.open	= vfio_mdev_pci_open;
> +	vmdev->ops.release = vfio_mdev_pci_release;
> +	vmdev->ops.read = vfio_mdev_pci_read;
> +	vmdev->ops.write = vfio_mdev_pci_write;
> +	vmdev->ops.mmap = vfio_mdev_pci_mmap;
> +	vmdev->ops.ioctl = vfio_mdev_pci_ioctl;
> +	ops = &vmdev->ops;
> +
> +	vdev = &vmdev->vdev;
>  	vdev->pdev = pdev;
>  	vdev->irq_type = VFIO_PCI_NUM_IRQS;
>  	mutex_init(&vdev->igate);
> @@ -289,7 +304,7 @@ static int vfio_mdev_pci_driver_probe(struct pci_dev *pdev,
>  #endif
>  	vdev->disable_idle_d3 = disable_idle_d3;
>  
> -	pci_set_drvdata(pdev, vdev);
> +	pci_set_drvdata(pdev, vmdev);
>  
>  	ret = vfio_pci_reflck_attach(vdev);
>  	if (ret) {
> @@ -320,7 +335,7 @@ static int vfio_mdev_pci_driver_probe(struct pci_dev *pdev,
>  		vfio_pci_set_power_state(vdev, PCI_D3hot);
>  	}
>  
> -	ret = mdev_register_device(&pdev->dev, &vfio_mdev_pci_ops);
> +	ret = mdev_register_device(&pdev->dev, ops);
>  	if (ret)
>  		pr_err("Cannot register mdev for device %s\n",
>  			dev_name(&pdev->dev));
> @@ -332,12 +347,17 @@ static int vfio_mdev_pci_driver_probe(struct pci_dev *pdev,
>  
>  static void vfio_mdev_pci_driver_remove(struct pci_dev *pdev)
>  {
> +	struct vfio_mdev_pci_device *vmdev;
>  	struct vfio_pci_device *vdev;
>  
> -	vdev = pci_get_drvdata(pdev);
> -	if (!vdev)
> +	mdev_unregister_device(&pdev->dev);
> +
> +	vmdev = pci_get_drvdata(pdev);
> +	if (!vmdev)
>  		return;
>  
> +	vdev = &vmdev->vdev;
> +
>  	vfio_pci_reflck_put(vdev->reflck);
>  
>  	kfree(vdev->region);
> @@ -355,7 +375,8 @@ static void vfio_mdev_pci_driver_remove(struct pci_dev *pdev)
>  				VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM);
>  	}
>  
> -	kfree(vdev);
> +	kfree(vmdev->attr.name);
> +	kfree(vmdev);
>  }
>  
>  static struct pci_driver vfio_mdev_pci_driver = {