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

Alex Williamson
2019-09-26T02:36:50Z

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

> From: Alex Williamson <alex.williamson@redhat.com>
>
> 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@intel.com>
> Cc: Lu Baolu <baolu.lu@linux.intel.com>
> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
> Signed-off-by: Liu Yi L <yi.l.liu@intel.com>
> ---
> 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 = {