Re: [PATCH v6 13/20] vfio/mdev: idxd: add mdev driver registration and helper functions

Jason Gunthorpe
2021-05-23T23:32:30Z

On Fri, May 21, 2021 at 05:20:26PM -0700, Dave Jiang wrote:
> +static int idxd_vdcm_mmap(struct vfio_device *vdev, struct vm_area_struct *vma)
> +{
> + unsigned int wq_idx;
> + unsigned long req_size, pgoff = 0, offset;
> + pgprot_t pg_prot;
> + struct vdcm_idxd *vidxd = vdev_to_vidxd(vdev);
> + struct idxd_wq *wq = vidxd->wq;
> + struct idxd_device *idxd = vidxd->idxd;
> + enum idxd_portal_prot virt_portal, phys_portal;
> + phys_addr_t base = pci_resource_start(idxd->pdev, IDXD_WQ_BAR);
> + struct device *dev = vdev->dev;
> +
> + if (!(vma->vm_flags & VM_SHARED))
> + return -EINVAL;
> +
> + pg_prot = vma->vm_page_prot;
> + req_size = vma->vm_end - vma->vm_start;
> + if (req_size > PAGE_SIZE)
> + return -EINVAL;
> +
> + vma->vm_flags |= VM_DONTCOPY;
> +
> + offset = (vma->vm_pgoff << PAGE_SHIFT) &
> + ((1ULL << VFIO_PCI_OFFSET_SHIFT) - 1);
> +
> + wq_idx = offset >> (PAGE_SHIFT + 2);
> + if (wq_idx >= 1) {
> + dev_err(dev, "mapping invalid wq %d off %lx\n",
> + wq_idx, offset);
> + return -EINVAL;
> + }

This is a really wonky and leaky way to say that the vm_pgoff can only
be one of two values? It is uAPI, be thorough.

> +static long idxd_vdcm_ioctl(struct vfio_device *vdev, unsigned int cmd, unsigned long arg)
> +{
> + struct vdcm_idxd *vidxd = vdev_to_vidxd(vdev);
> + unsigned long minsz;
> + int rc = -EINVAL;
> + struct device *dev = vdev->dev;
> +
> + dev_dbg(dev, "vidxd %p ioctl, cmd: %d\n", vidxd, cmd);
> +
> + mutex_lock(&vidxd->dev_lock);
> + if (cmd == VFIO_DEVICE_GET_INFO) {

Sigh.. This ioctl stuff really needs splitting into proper functions
called by the core code instead of cut&pasting all of this

> static int idxd_mdev_drv_probe(struct device *dev)
> diff --git a/drivers/vfio/mdev/idxd/mdev.h b/drivers/vfio/mdev/idxd/mdev.h
> index f696fe38e374..dd4290bce772 100644
> +++ b/drivers/vfio/mdev/idxd/mdev.h
> @@ -30,11 +30,26 @@
> #define VIDXD_MAX_MSIX_ENTRIES VIDXD_MAX_MSIX_VECS
> #define VIDXD_MAX_WQS 1
>
> +#define IDXD_MDEV_NAME_LEN 64

This is never used. Check everything..

Jason