From: Ard Biesheuvel Date: Sat, 9 Jan 2021 09:53:53 +0000 (+0100) Subject: PCI: Decline to resize resources if boot config must be preserved X-Git-Tag: v5.12-rc1~37^2~15^2 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=729e3a669d1b62e9876a671ac03ccba399a23b68;p=thirdparty%2Fkernel%2Flinux.git 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+ --- diff --git a/drivers/pci/setup-res.c b/drivers/pci/setup-res.c index 43eda101fcf40..7f1acb3918d0c 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;