From ecebe53fe99379243695e817450124d69e061e39 Mon Sep 17 00:00:00 2001 From: Shenming Lu Date: Wed, 10 Mar 2021 11:02:33 +0800 Subject: 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 Message-Id: <20210310030233.1133-4-lushenming@huawei.com> Signed-off-by: Alex Williamson --- 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 759a3b1abf..5c65aa0a98 100644 --- a/hw/vfio/pci.c +++ b/hw/vfio/pci.c @@ -569,6 +569,9 @@ 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); @@ -587,11 +590,22 @@ 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"); } -- cgit v1.2.3