Re: [PATCH v3 5/7] vfio: move barmap to a separate function and export

[Donald Dutile <ddutile@redhat.com>]

On 11/21/25 11:39 AM, Alex Williamson wrote:
> On Fri, 21 Nov 2025 14:11:39 +0000
> <ankita@nvidia.com> wrote:
> 
>> From: Ankit Agrawal <ankita@nvidia.com>
>>
>> Move the code to map the BAR to a separate function.
>>
>> This would be reused by the nvgrace-gpu module.
>>
>> Signed-off-by: Ankit Agrawal <ankita@nvidia.com>
>> ---
>>   drivers/vfio/pci/vfio_pci_core.c | 38 ++++++++++++++++++++++----------
>>   include/linux/vfio_pci_core.h    |  1 +
>>   2 files changed, 27 insertions(+), 12 deletions(-)
>>
>> diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
>> index 29dcf78905a6..d1ff1c0aa727 100644
>> --- a/drivers/vfio/pci/vfio_pci_core.c
>> +++ b/drivers/vfio/pci/vfio_pci_core.c
>> @@ -1717,6 +1717,29 @@ static const struct vm_operations_struct vfio_pci_mmap_ops = {
>>   #endif
>>   };
>>   
>> +int vfio_pci_core_barmap(struct vfio_pci_core_device *vdev, unsigned int index)
>> +{
>> +	struct pci_dev *pdev = vdev->pdev;
>> +	int ret;
>> +
>> +	if (vdev->barmap[index])
>> +		return 0;
>> +
>> +	ret = pci_request_selected_regions(pdev,
>> +					   1 << index, "vfio-pci");
>> +	if (ret)
>> +		return ret;
>> +
>> +	vdev->barmap[index] = pci_iomap(pdev, index, 0);
>> +	if (!vdev->barmap[index]) {
>> +		pci_release_selected_regions(pdev, 1 << index);
>> +		return -ENOMEM;
>> +	}
>> +
>> +	return 0;
>> +}
>> +EXPORT_SYMBOL_GPL(vfio_pci_core_barmap);
> 
> Looks a lot like vfio_pci_core_setup_barmap() ;)
> 
> Thanks,
> Alex
> 
+1 ... and below ...
> 
>> +
>>   int vfio_pci_core_mmap(struct vfio_device *core_vdev, struct vm_area_struct *vma)
>>   {
>>   	struct vfio_pci_core_device *vdev =
>> @@ -1761,18 +1784,9 @@ int vfio_pci_core_mmap(struct vfio_device *core_vdev, struct vm_area_struct *vma
>>   	 * Even though we don't make use of the barmap for the mmap,
>>   	 * we need to request the region and the barmap tracks that.
>>   	 */
>> -	if (!vdev->barmap[index]) {
>> -		ret = pci_request_selected_regions(pdev,
>> -						   1 << index, "vfio-pci");
>> -		if (ret)
>> -			return ret;
>> -
>> -		vdev->barmap[index] = pci_iomap(pdev, index, 0);
>> -		if (!vdev->barmap[index]) {
>> -			pci_release_selected_regions(pdev, 1 << index);
>> -			return -ENOMEM;
>> -		}
>> -	}
>> +	ret = vfio_pci_core_barmap(vdev, index);
>> +	if (ret)
>> +		return ret;
>>   
so, vfio_pci_core_mmap() should be calling vfio_pci_core_setup_barmap() vs. what it does above currently?

--Don

>>   	vma->vm_private_data = vdev;
>>   	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
>> diff --git a/include/linux/vfio_pci_core.h b/include/linux/vfio_pci_core.h
>> index a097a66485b4..75f04d613e0c 100644
>> --- a/include/linux/vfio_pci_core.h
>> +++ b/include/linux/vfio_pci_core.h
>> @@ -121,6 +121,7 @@ ssize_t vfio_pci_core_write(struct vfio_device *core_vdev, const char __user *bu
>>   		size_t count, loff_t *ppos);
>>   vm_fault_t vfio_pci_map_pfn(struct vm_fault *vmf, unsigned long pfn,
>>   			    unsigned int order);
>> +int vfio_pci_core_barmap(struct vfio_pci_core_device *vdev, unsigned int index);
>>   int vfio_pci_core_mmap(struct vfio_device *core_vdev, struct vm_area_struct *vma);
>>   void vfio_pci_core_request(struct vfio_device *core_vdev, unsigned int count);
>>   int vfio_pci_core_match(struct vfio_device *core_vdev, char *buf);
> 
>