[RFC PATCH 4/6] x86: PCI: preserve IORESOURCE_STARTALIGN alignment

Stewart Hildebrand
2024-07-09T13:36:51Z

Currently, it's not possible to use the IORESOURCE_STARTALIGN flag on
x86 due to the alignment being overwritten in
pcibios_allocate_dev_resources(). Make one small change in arch/x86 to
make it work on x86.

Signed-off-by: Stewart Hildebrand <stewart.hildebrand@amd.com>
---
RFC: We don't have enough info in this function to re-calculate the
alignment value in case of IORESOURCE_STARTALIGN. Luckily our
alignment value seems to be intact, so just don't touch it...
Alternatively, we could call pci_reassigndev_resource_alignment()
after the loop. Would that be preferable?
---
arch/x86/pci/i386.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/x86/pci/i386.c b/arch/x86/pci/i386.c
index f2f4a5d50b27..ff6e61389ec7 100644
--- a/arch/x86/pci/i386.c
+++ b/arch/x86/pci/i386.c
@@ -283,8 +283,11 @@ static void pcibios_allocate_dev_resources(struct pci_dev *dev, int pass)
/* We'll assign a new address later */
pcibios_save_fw_addr(dev,
idx, r->start);
- r->end -= r->start;
- r->start = 0;
+ if (!(r->flags &
+ IORESOURCE_STARTALIGN)) {
+ r->end -= r->start;
+ r->start = 0;
+ }
}
}
}
--
2.45.2