PCI: disable Bus Master on PCI device shutdown
Disable Bus Master bit on the device in pci_device_shutdown() to ensure PCI
devices do not continue to DMA data after shutdown. This can cause memory
corruption in case of a kexec where the current kernel shuts down and
transfers control to a new kernel while a PCI device continues to DMA to
memory that does not belong to it any more in the new kernel.
I have tested this code on two laptops, two workstations and a 16-socket
server. kexec worked correctly on all of them.
Signed-off-by: Khalid Aziz <khalid.aziz@hp.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
index 6b54b23..bf0cee6 100644
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -421,6 +421,12 @@
pci_msix_shutdown(pci_dev);
/*
+ * Turn off Bus Master bit on the device to tell it to not
+ * continue to do DMA
+ */
+ pci_disable_device(pci_dev);
+
+ /*
* Devices may be enabled to wake up by runtime PM, but they need not
* be supposed to wake up the system from its "power off" state (e.g.
* ACPI S5). Therefore disable wakeup for all devices that aren't