From 774345f981854b026e24aeb0833311183a8e8067 Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Fri, 21 Dec 2012 00:27:54 +0200 Subject: [PATCH] virtio-pci: cache msix messages Some guests mask a vector then unmask without changing it. Store vectors to avoid kvm system calls in this case. Signed-off-by: Michael S. Tsirkin --- hw/virtio-pci.c | 119 ++++++++++++++++++++++++++++++++++++++++++++++---------- hw/virtio-pci.h | 1 + 2 files changed, 100 insertions(+), 20 deletions(-) diff --git a/hw/virtio-pci.c b/hw/virtio-pci.c index 65a563b..6b6f25b 100644 --- a/hw/virtio-pci.c +++ b/hw/virtio-pci.c @@ -487,8 +487,6 @@ static int kvm_virtio_pci_vq_vector_use(VirtIOPCIProxy *proxy, unsigned int vector, MSIMessage msg) { - VirtQueue *vq = virtio_get_queue(proxy->vdev, queue_no); - EventNotifier *n = virtio_queue_get_guest_notifier(vq); VirtIOIRQFD *irqfd = &proxy->vector_irqfd[vector]; int ret; @@ -500,18 +498,94 @@ static int kvm_virtio_pci_vq_vector_use(VirtIOPCIProxy *proxy, irqfd->virq = ret; } irqfd->users++; + return 0; +} - ret = kvm_irqchip_add_irqfd_notifier(kvm_state, n, irqfd->virq); - if (ret < 0) { - if (--irqfd->users == 0) { - kvm_irqchip_release_virq(kvm_state, irqfd->virq); +static void kvm_virtio_pci_vq_vector_release(VirtIOPCIProxy *proxy, + unsigned int vector) +{ + VirtIOIRQFD *irqfd = &proxy->vector_irqfd[vector]; + if (--irqfd->users == 0) { + kvm_irqchip_release_virq(kvm_state, irqfd->virq); + } +} + +static int kvm_virtio_pci_vector_use(VirtIOPCIProxy *proxy, int nvqs) +{ + PCIDevice *dev = &proxy->pci_dev; + VirtIODevice *vdev = proxy->vdev; + unsigned int vector; + int ret, queue_no; + MSIMessage msg; + + for (queue_no = 0; queue_no < nvqs; queue_no++) { + if (!virtio_queue_get_num(vdev, queue_no)) { + break; + } + vector = virtio_queue_vector(vdev, queue_no); + if (vector >= msix_nr_vectors_allocated(dev)) { + continue; + } + msg = msix_get_message(dev, vector); + ret = kvm_virtio_pci_vq_vector_use(proxy, queue_no, vector, msg); + if (ret < 0) { + goto undo; } - return ret; } return 0; + +undo: + while (--queue_no >= 0) { + vector = virtio_queue_vector(vdev, queue_no); + if (vector >= msix_nr_vectors_allocated(dev)) { + continue; + } + kvm_virtio_pci_vq_vector_release(proxy, vector); + } + return ret; } -static void kvm_virtio_pci_vq_vector_release(VirtIOPCIProxy *proxy, +static void kvm_virtio_pci_vector_release(VirtIOPCIProxy *proxy, int nvqs) +{ + PCIDevice *dev = &proxy->pci_dev; + VirtIODevice *vdev = proxy->vdev; + unsigned int vector; + int queue_no; + + for (queue_no = 0; queue_no < nvqs; queue_no++) { + if (!virtio_queue_get_num(vdev, queue_no)) { + break; + } + vector = virtio_queue_vector(vdev, queue_no); + if (vector >= msix_nr_vectors_allocated(dev)) { + continue; + } + kvm_virtio_pci_vq_vector_release(proxy, vector); + } +} + +static int kvm_virtio_pci_vq_vector_unmask(VirtIOPCIProxy *proxy, + unsigned int queue_no, + unsigned int vector, + MSIMessage msg) +{ + VirtQueue *vq = virtio_get_queue(proxy->vdev, queue_no); + EventNotifier *n = virtio_queue_get_guest_notifier(vq); + VirtIOIRQFD *irqfd = &proxy->vector_irqfd[vector]; + int ret; + + if (irqfd->msg.data != msg.data || irqfd->msg.address != msg.address) { + ret = kvm_irqchip_update_msi_route(kvm_state, irqfd->virq, msg); + if (ret < 0) { + return ret; + } + } + + ret = kvm_irqchip_add_irqfd_notifier(kvm_state, n, irqfd->virq); + return ret; +} + +static void kvm_virtio_pci_vq_vector_mask(VirtIOPCIProxy *proxy, unsigned int queue_no, unsigned int vector) { @@ -522,13 +596,9 @@ static void kvm_virtio_pci_vq_vector_release(VirtIOPCIProxy *proxy, ret = kvm_irqchip_remove_irqfd_notifier(kvm_state, n, irqfd->virq); assert(ret == 0); - - if (--irqfd->users == 0) { - kvm_irqchip_release_virq(kvm_state, irqfd->virq); - } } -static int kvm_virtio_pci_vector_use(PCIDevice *dev, unsigned vector, +static int kvm_virtio_pci_vector_unmask(PCIDevice *dev, unsigned vector, MSIMessage msg) { VirtIOPCIProxy *proxy = container_of(dev, VirtIOPCIProxy, pci_dev); @@ -542,7 +612,7 @@ static int kvm_virtio_pci_vector_use(PCIDevice *dev, unsigned vector, if (virtio_queue_vector(vdev, queue_no) != vector) { continue; } - ret = kvm_virtio_pci_vq_vector_use(proxy, queue_no, vector, msg); + ret = kvm_virtio_pci_vq_vector_unmask(proxy, queue_no, vector, msg); if (ret < 0) { goto undo; } @@ -554,12 +624,12 @@ undo: if (virtio_queue_vector(vdev, queue_no) != vector) { continue; } - kvm_virtio_pci_vq_vector_release(proxy, queue_no, vector); + kvm_virtio_pci_vq_vector_mask(proxy, queue_no, vector); } return ret; } -static void kvm_virtio_pci_vector_release(PCIDevice *dev, unsigned vector) +static void kvm_virtio_pci_vector_mask(PCIDevice *dev, unsigned vector) { VirtIOPCIProxy *proxy = container_of(dev, VirtIOPCIProxy, pci_dev); VirtIODevice *vdev = proxy->vdev; @@ -572,7 +642,7 @@ static void kvm_virtio_pci_vector_release(PCIDevice *dev, unsigned vector) if (virtio_queue_vector(vdev, queue_no) != vector) { continue; } - kvm_virtio_pci_vq_vector_release(proxy, queue_no, vector); + kvm_virtio_pci_vq_vector_mask(proxy, queue_no, vector); } } @@ -651,6 +721,7 @@ static int virtio_pci_set_guest_notifiers(DeviceState *d, int nvqs, bool assign) /* Must unset vector notifier while guest notifier is still assigned */ if (proxy->vector_irqfd && !assign) { msix_unset_vector_notifiers(&proxy->pci_dev); + kvm_virtio_pci_vector_release(proxy, nvqs); g_free(proxy->vector_irqfd); proxy->vector_irqfd = NULL; } @@ -672,17 +743,25 @@ static int virtio_pci_set_guest_notifiers(DeviceState *d, int nvqs, bool assign) proxy->vector_irqfd = g_malloc0(sizeof(*proxy->vector_irqfd) * msix_nr_vectors_allocated(&proxy->pci_dev)); + r = kvm_virtio_pci_vector_use(proxy, nvqs); + if (r < 0) { + goto assign_error; + } r = msix_set_vector_notifiers(&proxy->pci_dev, - kvm_virtio_pci_vector_use, - kvm_virtio_pci_vector_release, + kvm_virtio_pci_vector_unmask, + kvm_virtio_pci_vector_mask, kvm_virtio_pci_vector_poll); if (r < 0) { - goto assign_error; + goto notifiers_error; } } return 0; +notifiers_error: + assert(assign); + kvm_virtio_pci_vector_release(proxy, nvqs); + assign_error: /* We get here on assignment failure. Recover by undoing for VQs 0 .. n. */ assert(assign); diff --git a/hw/virtio-pci.h b/hw/virtio-pci.h index b0f17e2..9ff3139 100644 --- a/hw/virtio-pci.h +++ b/hw/virtio-pci.h @@ -27,6 +27,7 @@ #define VIRTIO_PCI_FLAG_USE_IOEVENTFD (1 << VIRTIO_PCI_FLAG_USE_IOEVENTFD_BIT) typedef struct { + MSIMessage msg; int virq; unsigned int users; } VirtIOIRQFD; -- 2.7.4