Re: [PATCH 3/9] vfio/mdev: Pass in a struct vfio_device * to vfio_pin/unpin_pages()

Eric Farman
2022-04-14T19:26:44Z

On Tue, 2022-04-12 at 12:53 -0300, Jason Gunthorpe wrote:
> Every caller has a readily available vfio_device pointer, use that
> instead
> of passing in a generic struct device. The struct vfio_device already
> contains the group we need so this avoids complexity, extra
> refcountings,
> and a confusing lifecycle model.
>
> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
> ---
> .../driver-api/vfio-mediated-device.rst | 4 +-
> drivers/s390/cio/vfio_ccw_cp.c | 6 +--
> drivers/s390/crypto/vfio_ap_ops.c | 8 ++--
> drivers/vfio/vfio.c | 40 ++++++-----------
> --
> include/linux/vfio.h | 4 +-
> 5 files changed, 24 insertions(+), 38 deletions(-)

For the -ccw bits:

Acked-by: Eric Farman <farman@linux.ibm.com>

>
> diff --git a/Documentation/driver-api/vfio-mediated-device.rst
> b/Documentation/driver-api/vfio-mediated-device.rst
> index 9f26079cacae35..6aeca741dc9be1 100644
> --- a/Documentation/driver-api/vfio-mediated-device.rst
> +++ b/Documentation/driver-api/vfio-mediated-device.rst
> @@ -279,10 +279,10 @@ Translation APIs for Mediated Devices
> The following APIs are provided for translating user pfn to host pfn
> in a VFIO
> driver::
>
> - extern int vfio_pin_pages(struct device *dev, unsigned long
> *user_pfn,
> + extern int vfio_pin_pages(struct vfio_device *vdev, unsigned
> long *user_pfn,
> int npage, int prot, unsigned long
> *phys_pfn);
>
> - extern int vfio_unpin_pages(struct device *dev, unsigned long
> *user_pfn,
> + extern int vfio_unpin_pages(struct vfio_device *vdev, unsigned
> long *user_pfn,
> int npage);
>
> These functions call back into the back-end IOMMU module by using
> the pin_pages
> diff --git a/drivers/s390/cio/vfio_ccw_cp.c
> b/drivers/s390/cio/vfio_ccw_cp.c
> index af5048a1ba8894..e362cb962a7234 100644
> --- a/drivers/s390/cio/vfio_ccw_cp.c
> +++ b/drivers/s390/cio/vfio_ccw_cp.c
> @@ -103,13 +103,13 @@ static int pfn_array_pin(struct pfn_array *pa,
> struct vfio_device *vdev)
> {
> int ret = 0;
>
> - ret = vfio_pin_pages(vdev->dev, pa->pa_iova_pfn, pa->pa_nr,
> + ret = vfio_pin_pages(vdev, pa->pa_iova_pfn, pa->pa_nr,
> IOMMU_READ | IOMMU_WRITE, pa->pa_pfn);
>
> if (ret < 0) {
> goto err_out;
> } else if (ret > 0 && ret != pa->pa_nr) {
> - vfio_unpin_pages(vdev->dev, pa->pa_iova_pfn, ret);
> + vfio_unpin_pages(vdev, pa->pa_iova_pfn, ret);
> ret = -EINVAL;
> goto err_out;
> }
> @@ -127,7 +127,7 @@ static void pfn_array_unpin_free(struct pfn_array
> *pa, struct vfio_device *vdev)
> {
> /* Only unpin if any pages were pinned to begin with */
> if (pa->pa_nr)
> - vfio_unpin_pages(vdev->dev, pa->pa_iova_pfn, pa-
> >pa_nr);
> + vfio_unpin_pages(vdev, pa->pa_iova_pfn, pa->pa_nr);
> pa->pa_nr = 0;
> kfree(pa->pa_iova_pfn);
> }
> diff --git a/drivers/s390/crypto/vfio_ap_ops.c
> b/drivers/s390/crypto/vfio_ap_ops.c
> index 69768061cd7bd9..a10b3369d76c41 100644
> --- a/drivers/s390/crypto/vfio_ap_ops.c
> +++ b/drivers/s390/crypto/vfio_ap_ops.c
> @@ -124,7 +124,7 @@ static void vfio_ap_free_aqic_resources(struct
> vfio_ap_queue *q)
> q->saved_isc = VFIO_AP_ISC_INVALID;
> }
> if (q->saved_pfn && !WARN_ON(!q->matrix_mdev)) {
> - vfio_unpin_pages(mdev_dev(q->matrix_mdev->mdev),
> + vfio_unpin_pages(&q->matrix_mdev->vdev,
> &q->saved_pfn, 1);
> q->saved_pfn = 0;
> }
> @@ -258,7 +258,7 @@ static struct ap_queue_status
> vfio_ap_irq_enable(struct vfio_ap_queue *q,
> return status;
> }
>
> - ret = vfio_pin_pages(mdev_dev(q->matrix_mdev->mdev), &g_pfn, 1,
> + ret = vfio_pin_pages(&q->matrix_mdev->vdev, &g_pfn, 1,
> IOMMU_READ | IOMMU_WRITE, &h_pfn);
> switch (ret) {
> case 1:
> @@ -301,7 +301,7 @@ static struct ap_queue_status
> vfio_ap_irq_enable(struct vfio_ap_queue *q,
> break;
> case AP_RESPONSE_OTHERWISE_CHANGED:
> /* We could not modify IRQ setings: clear new
> configuration */
> - vfio_unpin_pages(mdev_dev(q->matrix_mdev->mdev),
> &g_pfn, 1);
> + vfio_unpin_pages(&q->matrix_mdev->vdev, &g_pfn, 1);
> kvm_s390_gisc_unregister(kvm, isc);
> break;
> default:
> @@ -1250,7 +1250,7 @@ static int vfio_ap_mdev_iommu_notifier(struct
> notifier_block *nb,
> struct vfio_iommu_type1_dma_unmap *unmap = data;
> unsigned long g_pfn = unmap->iova >> PAGE_SHIFT;
>
> - vfio_unpin_pages(mdev_dev(matrix_mdev->mdev), &g_pfn,
> 1);
> + vfio_unpin_pages(&matrix_mdev->vdev, &g_pfn, 1);
> return NOTIFY_OK;
> }
>
> diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
> index 8a5c46aa2bef61..24b92a45cfc8f1 100644
> --- a/drivers/vfio/vfio.c
> +++ b/drivers/vfio/vfio.c
> @@ -2142,32 +2142,26 @@
> EXPORT_SYMBOL(vfio_set_irqs_validate_and_prepare);
> * @phys_pfn[out]: array of host PFNs
> * Return error or number of pages pinned.
> */
> -int vfio_pin_pages(struct device *dev, unsigned long *user_pfn, int
> npage,
> +int vfio_pin_pages(struct vfio_device *vdev, unsigned long
> *user_pfn, int npage,
> int prot, unsigned long *phys_pfn)
> {
> struct vfio_container *container;
> - struct vfio_group *group;
> + struct vfio_group *group = vdev->group;
> struct vfio_iommu_driver *driver;
> int ret;
>
> - if (!dev || !user_pfn || !phys_pfn || !npage)
> + if (!user_pfn || !phys_pfn || !npage)
> return -EINVAL;
>
> if (npage > VFIO_PIN_PAGES_MAX_ENTRIES)
> return -E2BIG;
>
> - group = vfio_group_get_from_dev(dev);
> - if (!group)
> - return -ENODEV;
> -
> - if (group->dev_counter > 1) {
> - ret = -EINVAL;
> - goto err_pin_pages;
> - }
> + if (group->dev_counter > 1)
> + return -EINVAL;
>
> ret = vfio_group_add_container_user(group);
> if (ret)
> - goto err_pin_pages;
> + return ret;
>
> container = group->container;
> driver = container->iommu_driver;
> @@ -2180,8 +2174,6 @@ int vfio_pin_pages(struct device *dev, unsigned
> long *user_pfn, int npage,
>
> vfio_group_try_dissolve_container(group);
>
> -err_pin_pages:
> - vfio_group_put(group);
> return ret;
> }
> EXPORT_SYMBOL(vfio_pin_pages);
> @@ -2195,28 +2187,24 @@ EXPORT_SYMBOL(vfio_pin_pages);
> * be greater than VFIO_PIN_PAGES_MAX_ENTRIES.
> * Return error or number of pages unpinned.
> */
> -int vfio_unpin_pages(struct device *dev, unsigned long *user_pfn,
> int npage)
> +int vfio_unpin_pages(struct vfio_device *vdev, unsigned long
> *user_pfn,
> + int npage)
> {
> struct vfio_container *container;
> - struct vfio_group *group;
> struct vfio_iommu_driver *driver;
> int ret;
>
> - if (!dev || !user_pfn || !npage)
> + if (!user_pfn || !npage)
> return -EINVAL;
>
> if (npage > VFIO_PIN_PAGES_MAX_ENTRIES)
> return -E2BIG;
>
> - group = vfio_group_get_from_dev(dev);
> - if (!group)
> - return -ENODEV;
> -
> - ret = vfio_group_add_container_user(group);
> + ret = vfio_group_add_container_user(vdev->group);
> if (ret)
> - goto err_unpin_pages;
> + return ret;
>
> - container = group->container;
> + container = vdev->group->container;
> driver = container->iommu_driver;
> if (likely(driver && driver->ops->unpin_pages))
> ret = driver->ops->unpin_pages(container->iommu_data,
> user_pfn,
> @@ -2224,10 +2212,8 @@ int vfio_unpin_pages(struct device *dev,
> unsigned long *user_pfn, int npage)
> else
> ret = -ENOTTY;
>
> - vfio_group_try_dissolve_container(group);
> + vfio_group_try_dissolve_container(vdev->group);
>
> -err_unpin_pages:
> - vfio_group_put(group);
> return ret;
> }
> EXPORT_SYMBOL(vfio_unpin_pages);
> diff --git a/include/linux/vfio.h b/include/linux/vfio.h
> index 748ec0e0293aea..8f2a09801a660b 100644
> --- a/include/linux/vfio.h
> +++ b/include/linux/vfio.h
> @@ -150,9 +150,9 @@ extern long vfio_external_check_extension(struct
> vfio_group *group,
>
> #define VFIO_PIN_PAGES_MAX_ENTRIES (PAGE_SIZE/sizeof(unsigned
> long))
>
> -extern int vfio_pin_pages(struct device *dev, unsigned long
> *user_pfn,
> +extern int vfio_pin_pages(struct vfio_device *vdev, unsigned long
> *user_pfn,
> int npage, int prot, unsigned long
> *phys_pfn);
> -extern int vfio_unpin_pages(struct device *dev, unsigned long
> *user_pfn,
> +extern int vfio_unpin_pages(struct vfio_device *vdev, unsigned long
> *user_pfn,
> int npage);
>
> extern int vfio_group_pin_pages(struct vfio_group *group,