Re: [PATCH 15/52] fuse: map virtio_fs DAX window BAR

Christian Borntraeger
2018-12-12T16:37:35Z

On 10.12.2018 18:12, Vivek Goyal wrote:
> From: Stefan Hajnoczi <stefanha@redhat.com>

> +static int virtio_fs_setup_dax(struct virtio_device *vdev, struct virtio_fs *fs)
> +{
> + struct virtio_fs_memremap_info *mi;
> + struct dev_pagemap *pgmap;
> + struct pci_dev *pci_dev;
> + phys_addr_t phys_addr;
> + size_t len;
> + int ret;
> +
> + if (!IS_ENABLED(CONFIG_DAX_DRIVER))
> + return 0;
> +
> + /* HACK implement VIRTIO shared memory regions instead of
> + * directly accessing the PCI BAR from a virtio device driver.
> + */
> + pci_dev = container_of(vdev->dev.parent, struct pci_dev, dev);
> +
> + /* TODO Is this safe - the virtio_pci_* driver doesn't use managed
> + * device APIs? */
> + ret = pcim_enable_device(pci_dev);
> + if (ret < 0)
> + return ret;
> +
> + /* TODO handle case where device doesn't expose BAR? */
> + ret = pci_request_region(pci_dev, VIRTIO_FS_WINDOW_BAR,
> + "virtio-fs-window");
> + if (ret < 0) {
> + dev_err(&vdev->dev, "%s: failed to request window BAR\n",
> + __func__);
> + return ret;
> + }

Can we please have a generic virtio interface to map the address (the default can then
fall back to PCI) instead of mapping a PCI bar? This would make it easier to implement
virtio-ccw or virtio-mmio.