[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <CACGkMEv+myMJ1MXNz5RAfggkYy-0Q-VVyZKkpg_DD+_wfMxFQQ@mail.gmail.com>
Date: Thu, 7 Dec 2023 16:46:12 +0800
From: Jason Wang <jasowang@...hat.com>
To: Cindy Lu <lulu@...hat.com>
Cc: mst@...hat.com, xieyongji@...edance.com,
linux-kernel@...r.kernel.org, maxime.coquelin@...hat.com
Subject: Re: [PATCH v3 5/7] vduse: Add file operation for mmap
On Tue, Dec 5, 2023 at 4:35 PM Cindy Lu <lulu@...hat.com> wrote:
>
> Add the operation for mmap, This function will be used by the user space
> application to map the pages to the user space.
>
> Signed-off-by: Cindy Lu <lulu@...hat.com>
> ---
> drivers/vdpa/vdpa_user/vduse_dev.c | 75 ++++++++++++++++++++++++++++++
> 1 file changed, 75 insertions(+)
>
> diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
> index 52ccde636406..f55f415629de 100644
> --- a/drivers/vdpa/vdpa_user/vduse_dev.c
> +++ b/drivers/vdpa/vdpa_user/vduse_dev.c
> @@ -1381,6 +1381,79 @@ 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;
> + unsigned long vaddr;
> +
> + /* index 0 page reserved for vduse status*/
I'd suggest to tweak it as "reserved for device state"
> + if (index == 0) {
> + vaddr = dev->vdpa_reconnect_vaddr;
> + } else {
> + /* index 1+vq_number page reserved for vduse vqs*/
And "reserved for virtqueue state"
> + vq = &dev->vqs[index - 1];
> + vaddr = vq->vdpa_reconnect_vaddr;
> + }
> + if (remap_pfn_range(vma, vmf->address & PAGE_MASK,
> + PFN_DOWN(virt_to_phys((void *)vaddr)),
> + VDUSE_RECONNCT_MMAP_SIZE, vma->vm_page_prot))
If there's no chance for VDUSE_RECONNCT_MMAP_SIZE to differ from
PAGE_SIZE. Let's just use PAGE_SIZE here.
> + 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;
> + unsigned long vaddr = 0;
> + 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 itself, let's just drop the comment please.
> + if (index > dev->vq_num + 1)
> + return -EINVAL;
> +
> + /* index 0 page reserved for vduse status*/
This comment duplicates the one in fault. I'd suggest to move it to uAPI.
> + if (index == 0) {
> + vaddr = dev->vdpa_reconnect_vaddr;
> + } else {
> + /* index 1+vq_number page reserved for vduse vqs*/
> + vq = &dev->vqs[index - 1];
> + vaddr = vq->vdpa_reconnect_vaddr;
> + }
> + /* Check whether the memory for the mmap was allocated by the kernel.
> + * If not, this device may not have been created/destroyed correctly.
> + */
Code explains, so let's drop the comment.
> + if (vaddr == 0)
> + return -EOPNOTSUPP;
> +
> + /* check if the address is page aligned, if not,
> + * this address maybe damaged
> + */
And this comment.
Thanks
Powered by blists - more mailing lists