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author | Ying-Shiuan Pan <yingshiuan.pan@gmail.com> | 2015-05-12 11:10:50 +0300 |
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committer | Michael S. Tsirkin <mst@redhat.com> | 2015-06-01 14:18:55 +0200 |
commit | 434027badb421863b85ffdb4769966533c001cfa (patch) | |
tree | 5e8fba6a7f378a8cdd81ebe492f9414427e1583e /hw/virtio/virtio-mmio.c | |
parent | afcf905cff7971324c2706600ead35a1f41f417a (diff) | |
download | qemu-434027badb421863b85ffdb4769966533c001cfa.zip qemu-434027badb421863b85ffdb4769966533c001cfa.tar.gz qemu-434027badb421863b85ffdb4769966533c001cfa.tar.bz2 |
virtio-mmio: ioeventfd support
set_host_notifier and set_guest_notifiers supported by virtio-mmio now.
Most code copied from virtio-pci.
This makes it possible to use vhost-net with virtio-mmio,
improving performance by about 30%.
The kvm-arm does not yet support irqfd, need to fix the hard-coded part after
kvm-arm gets irqfd support.
Signed-off-by: Ying-Shiuan Pan <yingshiuan.pan@gmail.com>
Signed-off-by: Pavel Fedin <p.fedin@samsung.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'hw/virtio/virtio-mmio.c')
-rw-r--r-- | hw/virtio/virtio-mmio.c | 181 |
1 files changed, 181 insertions, 0 deletions
diff --git a/hw/virtio/virtio-mmio.c b/hw/virtio/virtio-mmio.c index a3cfd30..c8f7294 100644 --- a/hw/virtio/virtio-mmio.c +++ b/hw/virtio/virtio-mmio.c @@ -22,7 +22,9 @@ #include "hw/sysbus.h" #include "hw/virtio/virtio.h" #include "qemu/host-utils.h" +#include "sysemu/kvm.h" #include "hw/virtio/virtio-bus.h" +#include "qemu/error-report.h" /* #define DEBUG_VIRTIO_MMIO */ @@ -86,8 +88,96 @@ typedef struct { uint32_t guest_page_shift; /* virtio-bus */ VirtioBusState bus; + bool ioeventfd_disabled; + bool ioeventfd_started; } VirtIOMMIOProxy; +static int virtio_mmio_set_host_notifier_internal(VirtIOMMIOProxy *proxy, + int n, bool assign, + bool set_handler) +{ + VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus); + VirtQueue *vq = virtio_get_queue(vdev, n); + EventNotifier *notifier = virtio_queue_get_host_notifier(vq); + int r = 0; + + if (assign) { + r = event_notifier_init(notifier, 1); + if (r < 0) { + error_report("%s: unable to init event notifier: %d", + __func__, r); + return r; + } + virtio_queue_set_host_notifier_fd_handler(vq, true, set_handler); + memory_region_add_eventfd(&proxy->iomem, VIRTIO_MMIO_QUEUENOTIFY, 4, + true, n, notifier); + } else { + memory_region_del_eventfd(&proxy->iomem, VIRTIO_MMIO_QUEUENOTIFY, 4, + true, n, notifier); + virtio_queue_set_host_notifier_fd_handler(vq, false, false); + event_notifier_cleanup(notifier); + } + return r; +} + +static void virtio_mmio_start_ioeventfd(VirtIOMMIOProxy *proxy) +{ + VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus); + int n, r; + + if (!kvm_eventfds_enabled() || + proxy->ioeventfd_disabled || + proxy->ioeventfd_started) { + return; + } + + for (n = 0; n < VIRTIO_QUEUE_MAX; n++) { + if (!virtio_queue_get_num(vdev, n)) { + continue; + } + + r = virtio_mmio_set_host_notifier_internal(proxy, n, true, true); + if (r < 0) { + goto assign_error; + } + } + proxy->ioeventfd_started = true; + return; + +assign_error: + while (--n >= 0) { + if (!virtio_queue_get_num(vdev, n)) { + continue; + } + + r = virtio_mmio_set_host_notifier_internal(proxy, n, false, false); + assert(r >= 0); + } + proxy->ioeventfd_started = false; + error_report("%s: failed. Fallback to a userspace (slower).", __func__); +} + +static void virtio_mmio_stop_ioeventfd(VirtIOMMIOProxy *proxy) +{ + int r; + int n; + VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus); + + if (!proxy->ioeventfd_started) { + return; + } + + for (n = 0; n < VIRTIO_QUEUE_MAX; n++) { + if (!virtio_queue_get_num(vdev, n)) { + continue; + } + + r = virtio_mmio_set_host_notifier_internal(proxy, n, false, false); + assert(r >= 0); + } + proxy->ioeventfd_started = false; +} + static uint64_t virtio_mmio_read(void *opaque, hwaddr offset, unsigned size) { VirtIOMMIOProxy *proxy = (VirtIOMMIOProxy *)opaque; @@ -265,7 +355,16 @@ static void virtio_mmio_write(void *opaque, hwaddr offset, uint64_t value, virtio_update_irq(vdev); break; case VIRTIO_MMIO_STATUS: + if (!(value & VIRTIO_CONFIG_S_DRIVER_OK)) { + virtio_mmio_stop_ioeventfd(proxy); + } + virtio_set_status(vdev, value & 0xff); + + if (value & VIRTIO_CONFIG_S_DRIVER_OK) { + virtio_mmio_start_ioeventfd(proxy); + } + if (vdev->status == 0) { virtio_reset(vdev); } @@ -328,12 +427,92 @@ static void virtio_mmio_reset(DeviceState *d) { VirtIOMMIOProxy *proxy = VIRTIO_MMIO(d); + virtio_mmio_stop_ioeventfd(proxy); virtio_bus_reset(&proxy->bus); proxy->host_features_sel = 0; proxy->guest_features_sel = 0; proxy->guest_page_shift = 0; } +static int virtio_mmio_set_guest_notifier(DeviceState *d, int n, bool assign, + bool with_irqfd) +{ + VirtIOMMIOProxy *proxy = VIRTIO_MMIO(d); + VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus); + VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev); + VirtQueue *vq = virtio_get_queue(vdev, n); + EventNotifier *notifier = virtio_queue_get_guest_notifier(vq); + + if (assign) { + int r = event_notifier_init(notifier, 0); + if (r < 0) { + return r; + } + virtio_queue_set_guest_notifier_fd_handler(vq, true, with_irqfd); + } else { + virtio_queue_set_guest_notifier_fd_handler(vq, false, with_irqfd); + event_notifier_cleanup(notifier); + } + + if (vdc->guest_notifier_mask) { + vdc->guest_notifier_mask(vdev, n, !assign); + } + + return 0; +} + +static int virtio_mmio_set_guest_notifiers(DeviceState *d, int nvqs, + bool assign) +{ + VirtIOMMIOProxy *proxy = VIRTIO_MMIO(d); + VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus); + /* TODO: need to check if kvm-arm supports irqfd */ + bool with_irqfd = false; + int r, n; + + nvqs = MIN(nvqs, VIRTIO_QUEUE_MAX); + + for (n = 0; n < nvqs; n++) { + if (!virtio_queue_get_num(vdev, n)) { + break; + } + + r = virtio_mmio_set_guest_notifier(d, n, assign, with_irqfd); + if (r < 0) { + goto assign_error; + } + } + + return 0; + +assign_error: + /* We get here on assignment failure. Recover by undoing for VQs 0 .. n. */ + assert(assign); + while (--n >= 0) { + virtio_mmio_set_guest_notifier(d, n, !assign, false); + } + return r; +} + +static int virtio_mmio_set_host_notifier(DeviceState *opaque, int n, + bool assign) +{ + VirtIOMMIOProxy *proxy = VIRTIO_MMIO(opaque); + + /* Stop using ioeventfd for virtqueue kick if the device starts using host + * notifiers. This makes it easy to avoid stepping on each others' toes. + */ + proxy->ioeventfd_disabled = assign; + if (assign) { + virtio_mmio_stop_ioeventfd(proxy); + } + /* We don't need to start here: it's not needed because backend + * currently only stops on status change away from ok, + * reset, vmstop and such. If we do add code to start here, + * need to check vmstate, device state etc. */ + return virtio_mmio_set_host_notifier_internal(proxy, n, assign, false); +} + /* virtio-mmio device */ static void virtio_mmio_realizefn(DeviceState *d, Error **errp) @@ -375,6 +554,8 @@ static void virtio_mmio_bus_class_init(ObjectClass *klass, void *data) k->notify = virtio_mmio_update_irq; k->save_config = virtio_mmio_save_config; k->load_config = virtio_mmio_load_config; + k->set_host_notifier = virtio_mmio_set_host_notifier; + k->set_guest_notifiers = virtio_mmio_set_guest_notifiers; k->has_variable_vring_alignment = true; bus_class->max_dev = 1; } |