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

[Farhan Ali]

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@xxxxxxxxxxxxx>
Signed-off-by: Farhan Ali <alifm@xxxxxxxxxxxxx>
---
 drivers/vfio/pci/vfio_pci_core.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
index 3f11a9624b9c..6a184588ff23 100644
--- a/drivers/vfio/pci/vfio_pci_core.c
+++ b/drivers/vfio/pci/vfio_pci_core.c
@@ -554,6 +554,9 @@ static void vfio_pci_core_map_bars(struct vfio_pci_core_device *vdev)
 
 		vdev->barmap[bar] = IOMEM_ERR_PTR(-ENODEV);
 
+		if (pdev->non_mappable_bars)
+			continue;
+
 		if (!pci_resource_len(pdev, i))
 			continue;
 
-- 
2.43.0