From 729e3a669d1b62e9876a671ac03ccba399a23b68 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Sat, 9 Jan 2021 10:53:53 +0100 Subject: PCI: Decline to resize resources if boot config must be preserved The _DSM #5 method in the ACPI host bridge object tells us whether the OS must preserve the resource assignments done by firmware. If this is the case, we should not permit drivers to resize BARs on the fly. Make pci_resize_resource() take this into account. Link: https://lore.kernel.org/r/20210109095353.13417-1-ardb@kernel.org Signed-off-by: Ard Biesheuvel Signed-off-by: Bjorn Helgaas Cc: stable@vger.kernel.org # v5.4+ --- drivers/pci/setup-res.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'drivers/pci') diff --git a/drivers/pci/setup-res.c b/drivers/pci/setup-res.c index 43eda101fcf4..7f1acb3918d0 100644 --- a/drivers/pci/setup-res.c +++ b/drivers/pci/setup-res.c @@ -410,10 +410,16 @@ EXPORT_SYMBOL(pci_release_resource); int pci_resize_resource(struct pci_dev *dev, int resno, int size) { struct resource *res = dev->resource + resno; + struct pci_host_bridge *host; int old, ret; u32 sizes; u16 cmd; + /* Check if we must preserve the firmware's resource assignment */ + host = pci_find_host_bridge(dev->bus); + if (host->preserve_config) + return -ENOTSUPP; + /* Make sure the resource isn't assigned before resizing it. */ if (!(res->flags & IORESOURCE_UNSET)) return -EBUSY; -- cgit v1.2.3