Messages in this thread | | | From | Cindy Lu <> | Date | Sat, 25 Nov 2023 21:46:21 +0800 | Subject | Re: [PATCH v2 2/5] vduse: Add file operation for mmap |
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On Wed, Nov 22, 2023 at 2:14 PM Jason Wang <jasowang@redhat.com> wrote: > > On Tue, Nov 21, 2023 at 3:31 PM Cindy Lu <lulu@redhat.com> wrote: > > > > Add the operation for mmap, The user space APP will > > use this function to map the pages to userspace > > > > Signed-off-by: Cindy Lu <lulu@redhat.com> > > --- > > drivers/vdpa/vdpa_user/vduse_dev.c | 79 ++++++++++++++++++++++++++++++ > > 1 file changed, 79 insertions(+) > > > > diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c > > index 6209e2f00278..ccb30e98bab5 100644 > > --- a/drivers/vdpa/vdpa_user/vduse_dev.c > > +++ b/drivers/vdpa/vdpa_user/vduse_dev.c > > @@ -1376,6 +1376,83 @@ static struct vduse_dev *vduse_dev_get_from_minor(int minor) > > return dev; > > } > > > > +static vm_fault_t vduse_vm_fault(struct vm_fault *vmf) > > +{ > > + struct vduse_dev *dev = vmf->vma->vm_file->private_data; > > + struct vm_area_struct *vma = vmf->vma; > > + u16 index = vma->vm_pgoff; > > + struct vduse_virtqueue *vq; > > + struct vdpa_reconnect_info *info; > > + > > + /* index 0 page reserved for vduse status*/ > > + if (index == 0) { > > I'd avoid using magic numbers but a well defined uAPI for 0. > sure will Add this
> > + info = &dev->reconnect_info; > > + } else { > > + /* index 1+vq_number page reserved for vduse vqs*/ > > + vq = &dev->vqs[index - 1]; > > + info = &vq->reconnect_info; > > + } > > + if (remap_pfn_range(vma, vmf->address & PAGE_MASK, > > + PFN_DOWN(virt_to_phys((void *)info->vaddr)), > > + PAGE_SIZE, vma->vm_page_prot)) > > + return VM_FAULT_SIGBUS; > > + return VM_FAULT_NOPAGE; > > +} > > + > > +static const struct vm_operations_struct vduse_vm_ops = { > > + .fault = vduse_vm_fault, > > +}; > > + > > +static int vduse_dev_mmap(struct file *file, struct vm_area_struct *vma) > > +{ > > + struct vduse_dev *dev = file->private_data; > > + struct vdpa_reconnect_info *info; > > + unsigned long index = vma->vm_pgoff; > > + struct vduse_virtqueue *vq; > > + > > + if (vma->vm_end - vma->vm_start != PAGE_SIZE) > > + return -EINVAL; > > + if ((vma->vm_flags & VM_SHARED) == 0) > > + return -EINVAL; > > + > > + /*check if Userspace App map the page number larger than kernel allocated*/ > > Code explains themselves, such comment is not necessary. > sure will remove this > > + if (index > dev->vq_num + 1) > > + return -EINVAL; > > + > > + /* index 0 page reserved for vduse status*/ > > + if (index == 0) { > > + info = &dev->reconnect_info; > > + } else { > > + /* index 1+vq_number page reserved for vduse vqs*/ > > + vq = &dev->vqs[index - 1]; > > + info = &vq->reconnect_info; > > + } > > + /*check if map pages was allocated and inited by kernel */ > > Typo above. > > > + if (info->vaddr == 0) > > + return -EOPNOTSUPP; > > Under which condition can we reach here? > if the userApp call this mmap without call the dev_create,may cause this problem, So Add the check here thanks Cindy > > + > > + /* check if the address is page aligned, if not, > > + * this address maybe damaged > > + */ > > + if (virt_to_phys((void *)info->vaddr) & (PAGE_SIZE - 1)) > > + return -EINVAL; > > And here? > if the address is not page-aligned, this information may be damaged So add the check here > Thanks > > > + > > + /* check if Userspace App mapped the correct size > > + * the userspace App should map one page each time > > + */ > > + if (vma->vm_end - vma->vm_start != PAGE_SIZE) > > + return -EOPNOTSUPP; > > + /* VM_IO: set as a memory-mapped I/O region,This will for vq information > > + * VM_PFNMAP: only need the pure PFN > > + * VM_DONTEXPAND: do not need to use mremap() in this function > > + * VM_DONTDUMP:Do not include in the core dump > > + */ > > + vm_flags_set(vma, VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP); > > + vma->vm_ops = &vduse_vm_ops; > > + > > + return 0; > > +} > > + > > static int vduse_dev_open(struct inode *inode, struct file *file) > > { > > int ret; > > @@ -1408,6 +1485,8 @@ static const struct file_operations vduse_dev_fops = { > > .unlocked_ioctl = vduse_dev_ioctl, > > .compat_ioctl = compat_ptr_ioctl, > > .llseek = noop_llseek, > > + .mmap = vduse_dev_mmap, > > + > > }; > > > > static struct vduse_dev *vduse_dev_create(void) > > -- > > 2.34.3 > > >
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