From fa75115240f1930d2364484047ba6bb88ac2a6d2 Mon Sep 17 00:00:00 2001 From: Bjorn Helgaas Date: Thu, 25 Feb 2016 14:35:57 -0600 Subject: [PATCH] PCI: Disable IO/MEM decoding for devices with non-compliant BARs commit b84106b4e2290c081cdab521fa832596cdfea246 upstream. The PCI config header (first 64 bytes of each device's config space) is defined by the PCI spec so generic software can identify the device and manage its usage of I/O, memory, and IRQ resources. Some non-spec-compliant devices put registers other than BARs where the BARs should be. When the PCI core sizes these "BARs", the reads and writes it does may have unwanted side effects, and the "BAR" may appear to describe non-sensical address space. Add a flag bit to mark non-compliant devices so we don't touch their BARs. Turn off IO/MEM decoding to prevent the devices from consuming address space, since we can't read the BARs to find out what that address space would be. Signed-off-by: Bjorn Helgaas Tested-by: Andi Kleen Signed-off-by: Greg Kroah-Hartman Signed-off-by: Willy Tarreau --- drivers/pci/probe.c | 14 ++++++++++++++ include/linux/pci.h | 1 + 2 files changed, 15 insertions(+) diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 034a4d2964d6f..d332d55885f8f 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -173,6 +173,9 @@ int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type, struct pci_bus_region region; bool bar_too_big = false, bar_disabled = false; + if (dev->non_compliant_bars) + return 0; + mask = type ? PCI_ROM_ADDRESS_MASK : ~0; /* No printks while decoding is disabled! */ @@ -981,6 +984,7 @@ void set_pcie_hotplug_bridge(struct pci_dev *pdev) int pci_setup_device(struct pci_dev *dev) { u32 class; + u16 cmd; u8 hdr_type; struct pci_slot *slot; int pos = 0; @@ -1028,6 +1032,16 @@ int pci_setup_device(struct pci_dev *dev) /* device class may be changed after fixup */ class = dev->class >> 8; + if (dev->non_compliant_bars) { + pci_read_config_word(dev, PCI_COMMAND, &cmd); + if (cmd & (PCI_COMMAND_IO | PCI_COMMAND_MEMORY)) { + dev_info(&dev->dev, "device has non-compliant BARs; disabling IO/MEM decoding\n"); + cmd &= ~PCI_COMMAND_IO; + cmd &= ~PCI_COMMAND_MEMORY; + pci_write_config_word(dev, PCI_COMMAND, cmd); + } + } + switch (dev->hdr_type) { /* header type */ case PCI_HEADER_TYPE_NORMAL: /* standard header */ if (class == PCI_CLASS_BRIDGE_PCI) diff --git a/include/linux/pci.h b/include/linux/pci.h index 102136ab1a5f1..655ef37fd1396 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -330,6 +330,7 @@ struct pci_dev { unsigned int __aer_firmware_first:1; unsigned int broken_intx_masking:1; unsigned int io_window_1k:1; /* Intel P2P bridge 1K I/O windows */ + unsigned int non_compliant_bars:1; /* broken BARs; ignore them */ pci_dev_flags_t dev_flags; atomic_t enable_cnt; /* pci_enable_device has been called */ -- 2.47.2