Disable Bus Master bit on PCI device shutdown

Eric suggested I disable bus master bit in PCI susbsystem instead and that makes perfect sense. So here is take 2 on this patch. Please review and let me know if I missed anything.

Subject: [PATCH] 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.

---
 drivers/pci/pci-driver.c |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)

index 6b54b23..9db5940 100644
@@ -420,6 +420,12 @@ static void pci_device_shutdown(struct device *dev)
 	pci_msi_shutdown(pci_dev);
 	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.

1.7.8.3


-- 
Khalid


_______________________________________________
kexec mailing list
[email protected]
http://lists.infradead.org/mailman/listinfo/kexec