@@ -176,6 +176,9 @@ int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type,
u16 orig_cmd;
struct pci_bus_region region, inverted_region;
+ if (dev->non_compliant_bars)
+ return 0;
+
mask = type ? PCI_ROM_ADDRESS_MASK : ~0;
/* No printks while decoding is disabled! */
@@ -1137,6 +1140,7 @@ static void pci_msi_setup_pci_dev(struct pci_dev *dev)
int pci_setup_device(struct pci_dev *dev)
{
u32 class;
+ u16 cmd;
u8 hdr_type;
struct pci_slot *slot;
int pos = 0;
@@ -1184,6 +1188,16 @@ 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)
@@ -358,6 +358,7 @@ struct pci_dev {
unsigned int io_window_1k:1; /* Intel P2P bridge 1K I/O windows */
unsigned int irq_managed:1;
unsigned int has_secondary_link:1;
+ 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 */
This is a note to let you know that I have just added a patch titled PCI: Disable IO/MEM decoding for devices with non-compliant BARs to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue This patch is scheduled to be released in version 4.2.8-ckt7. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 4.2.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ---8<------------------------------------------------------------ From d390d1cdd03d9e880aabcda779a7e31df58c4c73 Mon Sep 17 00:00:00 2001 From: Bjorn Helgaas <bhelgaas@google.com> Date: Thu, 25 Feb 2016 14:35:57 -0600 Subject: 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 <bhelgaas@google.com> Tested-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- drivers/pci/probe.c | 14 ++++++++++++++ include/linux/pci.h | 1 + 2 files changed, 15 insertions(+) -- 2.7.4