diff mbox series

[v6,19/30] PCI: hotplug: movable BARs: Ignore the MEM BAR offsets from bootloader

Message ID 20191024171228.877974-20-s.miroshnichenko@yadro.com (mailing list archive)
State Not Applicable
Headers show
Series PCI: Allow BAR movement during hotplug | expand

Checks

Context Check Description
snowpatch_ozlabs/apply_patch success Successfully applied on branch powerpc/merge (6b450d0404ca83dc131dadffd40c5aa6f7a603af)
snowpatch_ozlabs/checkpatch fail Test checkpatch on branch powerpc/merge

Commit Message

Sergei Miroshnichenko Oct. 24, 2019, 5:12 p.m. UTC 
BAR allocation by BIOS/UEFI/bootloader/firmware may be non-optimal and
it may even clash with the kernel's BAR assignment algorithm.

For example, if no space was reserved for SR-IOV BARs, and this bridge
window is packed between immovable BARs (so it is unable to extend),
and if this window can't be moved, the next PCI rescan will fail, as
the kernel tries to find a space for all the BARs, including SR-IOV.

With this patch the kernel will use its own methods of BAR allocating
when possible, increasing the chances of successful hotplug.

Also add a workaround for implicitly used video BARs on x86.

Signed-off-by: Sergey Miroshnichenko <s.miroshnichenko@yadro.com>
---
 drivers/pci/probe.c | 10 ++++++++++
 1 file changed, 10 insertions(+)
diff mbox series

Patch

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 94bbdf9b9dc1..73452aa81417 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -305,6 +305,16 @@  int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type,
 			 pos, (unsigned long long)region.start);
 	}
 
+	if (pci_can_move_bars &&
+	    !(res->flags & IORESOURCE_IO) &&
+	    (dev->class >> 8) != PCI_CLASS_DISPLAY_VGA) {
+		pci_warn(dev, "ignore the current offset of BAR %llx-%llx\n",
+			 l64, l64 + sz64 - 1);
+		res->start = 0;
+		res->end = sz64 - 1;
+		res->flags |= IORESOURCE_SIZEALIGN;
+	}
+
 	goto out;