diff --git a/vfio-Avoid-disabling-and-enabling-vectors-repeatedly.patch b/vfio-Avoid-disabling-and-enabling-vectors-repeatedly.patch
new file mode 100644
index 0000000..e65b3a8
--- /dev/null
+++ b/vfio-Avoid-disabling-and-enabling-vectors-repeatedly.patch
@@ -0,0 +1,63 @@
+From 8113fdcf0c1383ae5b9542563656bea3753d834e Mon Sep 17 00:00:00 2001
+From: Shenming Lu <lushenming@huawei.com>
+Date: Wed, 10 Mar 2021 11:02:33 +0800
+Subject: [PATCH] vfio: Avoid disabling and enabling vectors repeatedly in VFIO
+ migration
+
+In VFIO migration resume phase and some guest startups, there are
+already unmasked vectors in the vector table when calling
+vfio_msix_enable(). So in order to avoid inefficiently disabling
+and enabling vectors repeatedly, let's allocate all needed vectors
+first and then enable these unmasked vectors one by one without
+disabling.
+
+Signed-off-by: Shenming Lu <lushenming@huawei.com>
+Message-Id: <20210310030233.1133-4-lushenming@huawei.com>
+Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
+---
+ hw/vfio/pci.c | 20 +++++++++++++++++---
+ 1 file changed, 17 insertions(+), 3 deletions(-)
+
+diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
+index a637c35e7a..da7c740bce 100644
+--- a/hw/vfio/pci.c
++++ b/hw/vfio/pci.c
+@@ -563,6 +563,9 @@ static void vfio_msix_vector_release(PCIDevice *pdev, unsigned int nr)
+ 
+ static void vfio_msix_enable(VFIOPCIDevice *vdev)
+ {
++    PCIDevice *pdev = &vdev->pdev;
++    unsigned int nr, max_vec = 0;
++
+     vfio_disable_interrupts(vdev);
+ 
+     vdev->msi_vectors = g_new0(VFIOMSIVector, vdev->msix->entries);
+@@ -581,11 +584,22 @@ static void vfio_msix_enable(VFIOPCIDevice *vdev)
+      * triggering to userspace, then immediately release the vector, leaving
+      * the physical device with no vectors enabled, but MSI-X enabled, just
+      * like the guest view.
++     * If there are already unmasked vectors (in migration resume phase and
++     * some guest startups) which will be enabled soon, we can allocate all
++     * of them here to avoid inefficiently disabling and enabling vectors
++     * repeatedly later.
+      */
+-    vfio_msix_vector_do_use(&vdev->pdev, 0, NULL, NULL);
+-    vfio_msix_vector_release(&vdev->pdev, 0);
++    if (!pdev->msix_function_masked) {
++        for (nr = 0; nr < msix_nr_vectors_allocated(pdev); nr++) {
++            if (!msix_is_masked(pdev, nr)) {
++                max_vec = nr;
++            }
++        }
++    }
++    vfio_msix_vector_do_use(pdev, max_vec, NULL, NULL);
++    vfio_msix_vector_release(pdev, max_vec);
+ 
+-    if (msix_set_vector_notifiers(&vdev->pdev, vfio_msix_vector_use,
++    if (msix_set_vector_notifiers(pdev, vfio_msix_vector_use,
+                                   vfio_msix_vector_release, NULL)) {
+         error_report("vfio: msix_set_vector_notifiers failed");
+     }
+-- 
+2.27.0
+