diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c index f22bb316b8c4..3d163ec6fb28 100644 --- a/drivers/vhost/vdpa.c +++ b/drivers/vhost/vdpa.c @@ -15,6 +15,7 @@ #include #include #include +#include #include #include #include @@ -739,12 +740,70 @@ static int vhost_vdpa_release(struct inode *inode, struct file *filep) return 0; } +static vm_fault_t vhost_vdpa_fault(struct vm_fault *vmf) +{ + struct vhost_vdpa *v = vmf->vma->vm_file->private_data; + struct vdpa_device *vdpa = v->vdpa; + const struct vdpa_config_ops *ops = vdpa->config; + struct vdpa_notification_area notify; + struct vm_area_struct *vma = vmf->vma; + u16 index = vma->vm_pgoff; + + notify = ops->get_vq_notification(vdpa, index); + + vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); + if (remap_pfn_range(vma, vmf->address & PAGE_MASK, + notify.addr >> PAGE_SHIFT, PAGE_SIZE, + vma->vm_page_prot)) + return VM_FAULT_SIGBUS; + + return VM_FAULT_NOPAGE; +} + +static const struct vm_operations_struct vhost_vdpa_vm_ops = { + .fault = vhost_vdpa_fault, +}; + +static int vhost_vdpa_mmap(struct file *file, struct vm_area_struct *vma) +{ + struct vhost_vdpa *v = vma->vm_file->private_data; + struct vdpa_device *vdpa = v->vdpa; + const struct vdpa_config_ops *ops = vdpa->config; + struct vdpa_notification_area notify; + int index = vma->vm_pgoff; + + if (vma->vm_end - vma->vm_start != PAGE_SIZE) + return -EINVAL; + if ((vma->vm_flags & VM_SHARED) == 0) + return -EINVAL; + if (vma->vm_flags & VM_READ) + return -EINVAL; + if (index > 65535) + return -EINVAL; + if (!ops->get_vq_notification) + return -ENOTSUPP; + + /* To be safe and easily modelled by userspace, We only + * support the doorbell which sits on the page boundary and + * does not share the page with other registers. + */ + notify = ops->get_vq_notification(vdpa, index); + if (notify.addr & (PAGE_SIZE - 1)) + return -EINVAL; + if (vma->vm_end - vma->vm_start != notify.size) + return -ENOTSUPP; + + vma->vm_ops = &vhost_vdpa_vm_ops; + return 0; +} + static const struct file_operations vhost_vdpa_fops = { .owner = THIS_MODULE, .open = vhost_vdpa_open, .release = vhost_vdpa_release, .write_iter = vhost_vdpa_chr_write_iter, .unlocked_ioctl = vhost_vdpa_unlocked_ioctl, + .mmap = vhost_vdpa_mmap, .compat_ioctl = compat_ptr_ioctl, };