> -----邮件原件-----
> 发件人: Alex Williamson [mailto:alex.william...@redhat.com]
> 发送时间: 2021年3月9日 5:47
> 收件人: alex.william...@redhat.com
> 抄送: coh...@redhat.com; k...@vger.kernel.org;
> linux-kernel@vger.kernel.org; j...@nvidia.com; pet...@redhat.com
> 主题: [PATCH v1 01/14] vfio: Create vfio_fs_type with inode per device
>
> By linking all the device fds we provide to userspace to an address space
> through a new pseudo fs, we can use tools like
> unmap_mapping_range() to zap all vmas associated with a device.
>
> Suggested-by: Jason Gunthorpe <j...@nvidia.com>
> Signed-off-by: Alex Williamson <alex.william...@redhat.com>
> ---
> drivers/vfio/vfio.c | 54
> +++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 54 insertions(+)
>
> diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c index
> 38779e6fd80c..abdf8d52a911 100644
> --- a/drivers/vfio/vfio.c
> +++ b/drivers/vfio/vfio.c
> @@ -32,11 +32,18 @@
> #include <linux/vfio.h>
> #include <linux/wait.h>
> #include <linux/sched/signal.h>
> +#include <linux/pseudo_fs.h>
> +#include <linux/mount.h>
Minor: keep the headers in alphabetical order.
>
> #define DRIVER_VERSION "0.3"
> #define DRIVER_AUTHOR "Alex Williamson <alex.william...@redhat.com>"
> #define DRIVER_DESC "VFIO - User Level meta-driver"
>
> +#define VFIO_MAGIC 0x5646494f /* "VFIO" */
Move to include/uapi/linux/magic.h ?
> +
> +static int vfio_fs_cnt;
> +static struct vfsmount *vfio_fs_mnt;
> +
> static struct vfio {
> struct class *class;
> struct list_head iommu_drivers_list;
> @@ -97,6 +104,7 @@ struct vfio_device {
> struct vfio_group *group;
> struct list_head group_next;
> void *device_data;
> + struct inode *inode;
> };
>
> #ifdef CONFIG_VFIO_NOIOMMU
> @@ -529,6 +537,34 @@ static struct vfio_group
> *vfio_group_get_from_dev(struct device *dev)
> return group;
> }
>
> +static int vfio_fs_init_fs_context(struct fs_context *fc) {
> + return init_pseudo(fc, VFIO_MAGIC) ? 0 : -ENOMEM; }
> +
> +static struct file_system_type vfio_fs_type = {
> + .name = "vfio",
> + .owner = THIS_MODULE,
> + .init_fs_context = vfio_fs_init_fs_context,
> + .kill_sb = kill_anon_super,
> +};
> +
> +static struct inode *vfio_fs_inode_new(void) {
> + struct inode *inode;
> + int ret;
> +
> + ret = simple_pin_fs(&vfio_fs_type, &vfio_fs_mnt, &vfio_fs_cnt);
> + if (ret)
> + return ERR_PTR(ret);
> +
> + inode = alloc_anon_inode(vfio_fs_mnt->mnt_sb);
> + if (IS_ERR(inode))
> + simple_release_fs(&vfio_fs_mnt, &vfio_fs_cnt);
> +
> + return inode;
> +}
> +
> /**
> * Device objects - create, release, get, put, search
> */
> @@ -539,11 +575,19 @@ struct vfio_device
> *vfio_group_create_device(struct vfio_group *group,
> void *device_data)
> {
> struct vfio_device *device;
> + struct inode *inode;
>
> device = kzalloc(sizeof(*device), GFP_KERNEL);
> if (!device)
> return ERR_PTR(-ENOMEM);
>
> + inode = vfio_fs_inode_new();
> + if (IS_ERR(inode)) {
> + kfree(device);
> + return ERR_CAST(inode);
> + }
> + device->inode = inode;
> +
> kref_init(&device->kref);
> device->dev = dev;
> device->group = group;
> @@ -574,6 +618,9 @@ static void vfio_device_release(struct kref *kref)
>
> dev_set_drvdata(device->dev, NULL);
>
> + iput(device->inode);
> + simple_release_fs(&vfio_fs_mnt, &vfio_fs_cnt);
> +
> kfree(device);
>
> /* vfio_del_group_dev may be waiting for this device */ @@ -1488,6
> +1535,13 @@ static int vfio_group_get_device_fd(struct vfio_group *group,
> char *buf)
> */
> filep->f_mode |= (FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE);
>
> + /*
> + * Use the pseudo fs inode on the device to link all mmaps
> + * to the same address space, allowing us to unmap all vmas
> + * associated to this device using unmap_mapping_range().
> + */
> + filep->f_mapping = device->inode->i_mapping;
> +
> atomic_inc(&group->container_users);
>
> fd_install(ret, filep);
