From patchwork Tue Nov 27 22:00:41 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [RFC,2/4] vfio-pci: Add support for MSI affinity Date: Tue, 27 Nov 2012 12:00:41 -0000 From: Alex Williamson X-Patchwork-Id: 202309 Message-Id: <20121127220041.5751.37650.stgit@bling.home> To: qemu-devel@nongnu.org Cc: kvm@vger.kernel.org When MSI is accelerated through KVM the vectors are only programmed when the guest first enables MSI support. Subsequent writes to the vector address or data fields are ignored. Unfortunately that means we're ignore updates done to adjust SMP affinity of the vectors. MSI SMP affinity already works in non-KVM mode because the address and data fields are read from their backing store on each interrupt. This patch stores the MSIMessage programmed into KVM so that we can determine when changes are made and update the routes. The message is stored for both MSI and MSI-X for consistency, but we only have a use for them in MSI mode. Signed-off-by: Alex Williamson --- hw/vfio_pci.c | 31 ++++++++++++++++++++++++++++--- 1 file changed, 28 insertions(+), 3 deletions(-) diff --git a/hw/vfio_pci.c b/hw/vfio_pci.c index 7c27834..49b9550 100644 --- a/hw/vfio_pci.c +++ b/hw/vfio_pci.c @@ -75,6 +75,7 @@ struct VFIODevice; typedef struct VFIOMSIVector { EventNotifier interrupt; /* eventfd triggered on interrupt */ struct VFIODevice *vdev; /* back pointer to device */ + MSIMessage msg; /* cache the MSI message so we know when it changes */ int virq; /* KVM irqchip route for QEMU bypass */ bool use; } VFIOMSIVector; @@ -574,6 +575,7 @@ static int vfio_msix_vector_use(PCIDevice *pdev, vector = &vdev->msi_vectors[nr]; vector->vdev = vdev; + vector->msg = msg; vector->use = true; msix_vector_use(pdev, nr); @@ -716,7 +718,6 @@ retry: vdev->msi_vectors = g_malloc0(vdev->nr_vectors * sizeof(VFIOMSIVector)); for (i = 0; i < vdev->nr_vectors; i++) { - MSIMessage msg; VFIOMSIVector *vector = &vdev->msi_vectors[i]; vector->vdev = vdev; @@ -726,13 +727,13 @@ retry: error_report("vfio: Error: event_notifier_init failed\n"); } - msg = msi_get_message(&vdev->pdev, i); + vector->msg = msi_get_message(&vdev->pdev, i); /* * Attempt to enable route through KVM irqchip, * default to userspace handling if unavailable. */ - vector->virq = kvm_irqchip_add_msi_route(kvm_state, msg); + vector->virq = kvm_irqchip_add_msi_route(kvm_state, vector->msg); if (vector->virq < 0 || kvm_irqchip_add_irqfd_notifier(kvm_state, &vector->interrupt, vector->virq) < 0) { @@ -1022,6 +1023,30 @@ static void vfio_pci_write_config(PCIDevice *pdev, uint32_t addr, vfio_enable_msi(vdev); } else if (was_enabled && !is_enabled) { vfio_disable_msi(vdev); + } else if (was_enabled && is_enabled) { + int i; + + for (i = 0; i < vdev->nr_vectors; i++) { + VFIOMSIVector *vector = &vdev->msi_vectors[i]; + MSIMessage msg; + + if (!vector->use || vector->virq < 0) { + continue; + } + + msg = msi_get_message(pdev, i); + + if (msg.address != vector->msg.address || + msg.data != vector->msg.data) { + + DPRINTF("%s(%04x:%02x:%02x.%x) MSI vector %d changed\n", + __func__, vdev->host.domain, vdev->host.bus, + vdev->host.slot, vdev->host.function, i); + + kvm_irqchip_update_msi_route(kvm_state, vector->virq, msg); + vector->msg = msg; + } + } } }