Re: [PATCH v1] vfio/pci: Avoid mapping BARs for devices with non-mappable BARs

[sashiko-bot@kernel.org]

> vfio_pci_core_map_bars() calls pci_iomap() to set up BAR resources, but not
> all devices support having their BARs mapped by the CPU. The
> non_mappable_bars flag indicates that a PCI device's BARs cannot be
> accessed by the CPU. The ISM device on s390 is one such device. The BAR
> size for an ISM device is 256 TiB, and attempting to map the BAR will lead
> to warnings:
> 
> vmalloc_node_range for size 281474976714752 failed: Address range
> restricted to 0x2110bab00000 - 0x21903ab00000
> 
> Use pdev->non_mappable_bars to skip pci_iomap() for such devices. This flag
> is set by the PCI core at enumeration time and already serves the same
> purpose in vfio_pci_probe_mmaps().
> 
> Fixes: 05f2a68b407a ("vfio/pci: Set up BAR resources and maps in vfio_pci_core_enable()")
> Reported-by: Christian Borntraeger <borntraeger@linux.ibm.com>
> Signed-off-by: Farhan Ali <alifm@linux.ibm.com>

Sashiko has reviewed this patch and found no issues. It looks great!

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Sashiko AI review · https://sashiko.dev/#/patchset/20260729181116.1373-1-alifm@linux.ibm.com?part=1