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path: root/drivers/vfio/pci/vfio_pci_intrs.c
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Diffstat (limited to 'drivers/vfio/pci/vfio_pci_intrs.c')
-rw-r--r--drivers/vfio/pci/vfio_pci_intrs.c15
1 files changed, 15 insertions, 0 deletions
diff --git a/drivers/vfio/pci/vfio_pci_intrs.c b/drivers/vfio/pci/vfio_pci_intrs.c
index 9dd49c9839ac..553212f037c3 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) {