On 2021/3/3 5:26, Alex Williamson wrote: > > MST/Marcel, > > Do you have an Ack or objection to exporting msix_masked() as below?
Or could we use msix_function_masked instead as below? :-) if (!pdev->msix_function_masked) { for (nr = 0; nr < msix_nr_vectors_allocated(pdev); nr++) { if (!msix_is_masked(pdev, nr)) { max_vec = nr; } } } Thanks, Shenming > Thanks, > > Alex > > On Tue, 23 Feb 2021 10:22:25 +0800 > Shenming Lu <lushenm...@huawei.com> wrote: > >> 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 <lushenm...@huawei.com> >> --- >> hw/pci/msix.c | 2 +- >> hw/vfio/pci.c | 20 +++++++++++++++++--- >> include/hw/pci/msix.h | 1 + >> 3 files changed, 19 insertions(+), 4 deletions(-) >> >> diff --git a/hw/pci/msix.c b/hw/pci/msix.c >> index ae9331cd0b..e057958fcd 100644 >> --- a/hw/pci/msix.c >> +++ b/hw/pci/msix.c >> @@ -131,7 +131,7 @@ static void msix_handle_mask_update(PCIDevice *dev, int >> vector, bool was_masked) >> } >> } >> >> -static bool msix_masked(PCIDevice *dev) >> +bool msix_masked(PCIDevice *dev) >> { >> return dev->config[dev->msix_cap + MSIX_CONTROL_OFFSET] & >> MSIX_MASKALL_MASK; >> } >> diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c >> index f74be78209..088fd41926 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 (!msix_masked(pdev)) { >> + 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"); >> } >> diff --git a/include/hw/pci/msix.h b/include/hw/pci/msix.h >> index 4c4a60c739..b3cd88e262 100644 >> --- a/include/hw/pci/msix.h >> +++ b/include/hw/pci/msix.h >> @@ -28,6 +28,7 @@ void msix_load(PCIDevice *dev, QEMUFile *f); >> >> int msix_enabled(PCIDevice *dev); >> int msix_present(PCIDevice *dev); >> +bool msix_masked(PCIDevice *dev); >> >> bool msix_is_masked(PCIDevice *dev, unsigned vector); >> void msix_set_pending(PCIDevice *dev, unsigned vector); > > . >