| Message ID | 1411796591-3500-2-git-send-email-gwshan@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Sat, 2014-09-27 at 15:43 +1000, Gavin Shan wrote: > The MSIx vector table lives in device memory, which may be cleared as > part of a backdoor device reset. This is the case on the IBM IPR HBA > when the BIST is run on the device. When assigned to a QEMU guest, > the guest driver does a pci_save_state(), issues a BIST, then does a > pci_restore_state(). The BIST clears the MSIx vector table, but due > to the way interrupts are configured the pci_restore_state() does not > restore the vector table as expected. Eventually this results in an > EEH error on Power platforms when the device attempts to signal an > interrupt with the zero'd table entry. > > Fix the problem by restoring the host cached MSI message prior to > enabling each vector. > > Reported-by: Wen Xiong <wenxiong@linux.vnet.ibm.com> > Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com> > Signed-off-by: Alex Williamson <alex.williamson@redhat.com> > --- > drivers/vfio/pci/vfio_pci_intrs.c | 15 +++++++++++++++ > 1 file changed, 15 insertions(+) Applied both to linux-vfio.git/next for 3.18. Thanks! Alex > diff --git a/drivers/vfio/pci/vfio_pci_intrs.c b/drivers/vfio/pci/vfio_pci_intrs.c > index 9dd49c9..553212f 100644 > --- a/drivers/vfio/pci/vfio_pci_intrs.c > +++ b/drivers/vfio/pci/vfio_pci_intrs.c > @@ -16,6 +16,7 @@ > #include <linux/device.h> > #include <linux/interrupt.h> > #include <linux/eventfd.h> > +#include <linux/msi.h> > #include <linux/pci.h> > #include <linux/file.h> > #include <linux/poll.h> > @@ -548,6 +549,20 @@ static int vfio_msi_set_vector_signal(struct vfio_pci_device *vdev, > return PTR_ERR(trigger); > } > > + /* > + * The MSIx vector table resides in device memory which may be cleared > + * via backdoor resets. We don't allow direct access to the vector > + * table so even if a userspace driver attempts to save/restore around > + * such a reset it would be unsuccessful. To avoid this, restore the > + * cached value of the message prior to enabling. > + */ > + if (msix) { > + struct msi_msg msg; > + > + get_cached_msi_msg(irq, &msg); > + write_msi_msg(irq, &msg); > + } > + > ret = request_irq(irq, vfio_msihandler, 0, > vdev->ctx[vector].name, trigger); > if (ret) { -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/vfio/pci/vfio_pci_intrs.c b/drivers/vfio/pci/vfio_pci_intrs.c index 9dd49c9..553212f 100644 --- a/drivers/vfio/pci/vfio_pci_intrs.c +++ b/drivers/vfio/pci/vfio_pci_intrs.c @@ -16,6 +16,7 @@ #include <linux/device.h> #include <linux/interrupt.h> #include <linux/eventfd.h> +#include <linux/msi.h> #include <linux/pci.h> #include <linux/file.h> #include <linux/poll.h> @@ -548,6 +549,20 @@ static int vfio_msi_set_vector_signal(struct vfio_pci_device *vdev, return PTR_ERR(trigger); } + /* + * The MSIx vector table resides in device memory which may be cleared + * via backdoor resets. We don't allow direct access to the vector + * table so even if a userspace driver attempts to save/restore around + * such a reset it would be unsuccessful. To avoid this, restore the + * cached value of the message prior to enabling. + */ + if (msix) { + struct msi_msg msg; + + get_cached_msi_msg(irq, &msg); + write_msi_msg(irq, &msg); + } + ret = request_irq(irq, vfio_msihandler, 0, vdev->ctx[vector].name, trigger); if (ret) {