On Fri, Apr 27, 2012 at 1:00 PM, Khalid Aziz <khalid.aziz@xxxxxx> wrote: > 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@xxxxxx> > --- > drivers/pci/pci-driver.c | 6 ++++++ > 1 files changed, 6 insertions(+), 0 deletions(-) > > diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c > index 6b54b23..9db5940 100644 > --- a/drivers/pci/pci-driver.c > +++ b/drivers/pci/pci-driver.c > @@ -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. Any comment on this, Eric? It seems reasonable to me. -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
