Re: [PATCH v2 2/3] vfio/pci: Replace vfio_pci_core_setup_barmap() with checks for resource/map

[Leon Romanovsky <leon@kernel.org>]

On Thu, Apr 23, 2026 at 11:25:08AM -0700, Matt Evans wrote:
> Since "vfio/pci: Set up barmap in vfio_pci_core_enable()", the
> resource request and iomap for the BARs was performed early, and
> vfio_pci_core_setup_barmap() now just checks those actions succeeded.
> 
> There were two types of callers:
>  - Those that need the iomap, because they'll access the BAR
>  - Those that need the resource, because they'll map/export it
> 
> This replaces vfio_pci_core_setup_barmap() with two helpers,
> vfio_pci_core_check_barmap_valid() and vfio_pci_core_check_bar_rsrc(),
> to make it clear which behaviour is required in each caller.
> 
> Signed-off-by: Matt Evans <mattev@meta.com>
> ---
>  drivers/vfio/pci/nvgrace-gpu/main.c |  8 +++-----
>  drivers/vfio/pci/vfio_pci_core.c    |  5 ++---
>  drivers/vfio/pci/vfio_pci_rdwr.c    | 22 ++--------------------
>  drivers/vfio/pci/virtio/legacy_io.c |  4 ++--
>  include/linux/vfio_pci_core.h       | 23 ++++++++++++++++++++++-
>  5 files changed, 31 insertions(+), 31 deletions(-)

<...>

> +/* Returns 0 if vdev->barmap[bar] can be accessed, otherwise errno */
> +static inline int
> +vfio_pci_core_check_barmap_valid(struct vfio_pci_core_device *vdev, int bar)
> +{
> +	if (bar < 0 || bar >= PCI_STD_NUM_BARS)
> +		return -EINVAL;
> +	if (vdev->barmap[bar] == 0)

I understand this line was copied from an earlier implementation, but
barmap[bar] is a pointer, and it is set to NULL when it is released.

 if (!dev->barmap[bar])
   return -ENOMEM;

Thanks

> +		return -ENOMEM;
> +	return 0;
> +}
> +
> +/* Returns 0 if BAR has a valid resource reserved for use, otherwise errno */
> +static inline int vfio_pci_core_check_bar_rsrc(struct vfio_pci_core_device *vdev,
> +					       int bar)
> +{
> +	if (bar < 0 || bar >= PCI_STD_NUM_BARS)
> +		return -EINVAL;
> +	if (!vdev->have_bar_resource[bar])
> +		return -EBUSY;
> +	return 0;
> +}
> +
>  static inline bool is_aligned_for_order(struct vm_area_struct *vma,
>  					unsigned long addr,
>  					unsigned long pfn,
> -- 
> 2.47.3
>