@@ -17,6 +17,7 @@
#include <linux/interrupt.h>
#include <linux/eventfd.h>
#include <linux/pci.h>
+#include <linux/msi.h>
#include <linux/file.h>
#include <linux/poll.h>
#include <linux/vfio.h>
@@ -517,6 +518,7 @@ static int vfio_msi_set_vector_signal(struct vfio_pci_device *vdev,
struct pci_dev *pdev = vdev->pdev;
int irq = msix ? vdev->msix[vector].vector : pdev->irq + vector;
char *name = msix ? "vfio-msix" : "vfio-msi";
+ struct msi_msg msg;
struct eventfd_ctx *trigger;
int ret;
@@ -544,6 +546,15 @@ static int vfio_msi_set_vector_signal(struct vfio_pci_device *vdev,
return PTR_ERR(trigger);
}
+ /* We possiblly lose the MSI/MSIx message in some cases, one
+ * of which is pci_save_state(), BIST reset and pci_restore_state()
+ * for IPR adapter. The BIST reset cleans out MSIx table and we
+ * don't have chance to restore it. Here, we have the trick to
+ * restore it before enabling individual interrupts. For MSI messages,
+ * it's harmless to write them back.
+ */
+ 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) {
The problem is specific to the case of BIST reset issued to IPR adapter on the guest side. The IPR driver calls pci_save_state(), issues BIST reset and then pci_restore_state(). The issued BIST cleans out MSIx table and pci_restore_state() doesn't restore the MSIx table as expected. Eventually, MSIx messages with all zeros are sent and causes EEH error on Power platform. The patch fixes it by writing MSIx message to MSIx table before reenabling the individual interrupts in the following path: qemu/hw/pci/msix.c::msix_table_mmio_write msix_handle_mask_update msix_fire_vector_notifier qemu/hw/misc/vfio.c::vfio_msix_vector_use vfio_msix_vector_do_use IOCTL Command VFIO_DEVICE_SET_IRQS to VFIO-PCI vfio/pci/vfio_pci.c::vfio_pci_ioctl vfio/pci/vfio_pci_intrs.c::vfio_pci_set_irqs_ioctl vfio_pci_set_msi_trigger vfio_msi_set_block vfio_msi_set_vector_signal Reported-by: Wen Xiong <wenxiong@us.ibm.com> Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com> --- drivers/vfio/pci/vfio_pci_intrs.c | 11 +++++++++++ 1 file changed, 11 insertions(+)