From 468bf1861a9c2f62eda7b05eb90de3e2eb1b41c9 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Sat, 9 Jan 2021 10:53:53 +0100 Subject: [PATCH] PCI: Decline to resize resources if boot config must be preserved commit 729e3a669d1b62e9876a671ac03ccba399a23b68 upstream. 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+ Signed-off-by: Greg Kroah-Hartman --- drivers/pci/setup-res.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/pci/setup-res.c b/drivers/pci/setup-res.c index d21fa04fa44d..da5023e27951 100644 --- a/drivers/pci/setup-res.c +++ b/drivers/pci/setup-res.c @@ -409,10 +409,16 @@ 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;