义乌专业做网站的,网站流量在哪设置,大连网站建设金豆,网站开发运营产品经理招聘接前一篇文章#xff1a; 通过前文书#xff08;从QEMU源码全解析 —— virtio#xff08;9#xff09;开始#xff09;对整个流程以及各个相关函数的解析#xff0c;可以看到从virtio PCI代理设备的具现化到virtio设备的具现化过程。但前述分析还遗漏了一部分#xff0…接前一篇文章 通过前文书从QEMU源码全解析 —— virtio9开始对整个流程以及各个相关函数的解析可以看到从virtio PCI代理设备的具现化到virtio设备的具现化过程。但前述分析还遗漏了一部分就是virtio设备挂载到virtio总线上的行为。这个过程是在virtio_device_realize函数中通过调用virtio_bus_device_plugged函数完成的。在QEMU源码全解析 —— virtio11中提到过有图为证 virtio_bus_device_plugged函数的作用就是将virtio设备插入到virtio总线上去。其源码在hw/virtio/virtio-bus.c中如下
/* A VirtIODevice is being plugged */
void virtio_bus_device_plugged(VirtIODevice *vdev, Error **errp)
{DeviceState *qdev DEVICE(vdev);BusState *qbus BUS(qdev_get_parent_bus(qdev));VirtioBusState *bus VIRTIO_BUS(qbus);VirtioBusClass *klass VIRTIO_BUS_GET_CLASS(bus);VirtioDeviceClass *vdc VIRTIO_DEVICE_GET_CLASS(vdev);bool has_iommu virtio_host_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM);bool vdev_has_iommu;Error *local_err NULL;DPRINTF(%s: plug device.\n, qbus-name);if (klass-pre_plugged ! NULL) {klass-pre_plugged(qbus-parent, local_err);if (local_err) {error_propagate(errp, local_err);return;}}/* Get the features of the plugged device. */assert(vdc-get_features ! NULL);vdev-host_features vdc-get_features(vdev, vdev-host_features,local_err);if (local_err) {error_propagate(errp, local_err);return;}if (klass-device_plugged ! NULL) {klass-device_plugged(qbus-parent, local_err);}if (local_err) {error_propagate(errp, local_err);return;}vdev-dma_as address_space_memory;if (has_iommu) {vdev_has_iommu virtio_host_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM);/** Present IOMMU_PLATFORM to the driver iff iommu_plattformon and* device operational. If the driver does not accept IOMMU_PLATFORM* we fail the device.*/virtio_add_feature(vdev-host_features, VIRTIO_F_IOMMU_PLATFORM);if (klass-get_dma_as) {vdev-dma_as klass-get_dma_as(qbus-parent);if (!vdev_has_iommu vdev-dma_as ! address_space_memory) {error_setg(errp,iommu_platformtrue is not supported by the device);return;}}}
}
virtio_bus_device_plugged函数主要是调用了VirtioBusClass类型的device_plugged回调函数。代码片段如下 VirtioBusClass *klass VIRTIO_BUS_GET_CLASS(bus);……if (klass-device_plugged ! NULL) {klass-device_plugged(qbus-parent, local_err);}if (local_err) {error_propagate(errp, local_err);return;}
device_pluggeg回调函数也即klass-device_plugged函数指针所指向的函数在virtio_pci_bus_class_init函数中被初始化成了virtio_pci_device_plugged函数。virtio_pci_bus_class_init函数在hw/virtio/virtio-pci.c中代码如下
static void virtio_pci_bus_class_init(ObjectClass *klass, void *data)
{BusClass *bus_class BUS_CLASS(klass);VirtioBusClass *k VIRTIO_BUS_CLASS(klass);bus_class-max_dev 1;k-notify virtio_pci_notify;k-save_config virtio_pci_save_config;k-load_config virtio_pci_load_config;k-save_queue virtio_pci_save_queue;k-load_queue virtio_pci_load_queue;k-save_extra_state virtio_pci_save_extra_state;k-load_extra_state virtio_pci_load_extra_state;k-has_extra_state virtio_pci_has_extra_state;k-query_guest_notifiers virtio_pci_query_guest_notifiers;k-set_guest_notifiers virtio_pci_set_guest_notifiers;k-set_host_notifier_mr virtio_pci_set_host_notifier_mr;k-vmstate_change virtio_pci_vmstate_change;k-pre_plugged virtio_pci_pre_plugged;k-device_plugged virtio_pci_device_plugged;k-device_unplugged virtio_pci_device_unplugged;k-query_nvectors virtio_pci_query_nvectors;k-ioeventfd_enabled virtio_pci_ioeventfd_enabled;k-ioeventfd_assign virtio_pci_ioeventfd_assign;k-get_dma_as virtio_pci_get_dma_as;k-iommu_enabled virtio_pci_iommu_enabled;k-queue_enabled virtio_pci_queue_enabled;
}virtio_pci_device_plugged函数在hw/virtio/virtio-pci.c中代码如下
/* This is called by virtio-bus just after the device is plugged. */
static void virtio_pci_device_plugged(DeviceState *d, Error **errp)
{VirtIOPCIProxy *proxy VIRTIO_PCI(d);VirtioBusState *bus proxy-bus;bool legacy virtio_pci_legacy(proxy);bool modern;bool modern_pio proxy-flags VIRTIO_PCI_FLAG_MODERN_PIO_NOTIFY;uint8_t *config;uint32_t size;VirtIODevice *vdev virtio_bus_get_device(proxy-bus);/** Virtio capabilities present without* VIRTIO_F_VERSION_1 confuses guests*/if (!proxy-ignore_backend_features !virtio_has_feature(vdev-host_features, VIRTIO_F_VERSION_1)) {virtio_pci_disable_modern(proxy);if (!legacy) {error_setg(errp, Device doesnt support modern mode, and legacy mode is disabled);error_append_hint(errp, Set disable-legacy to off\n);return;}}modern virtio_pci_modern(proxy);config proxy-pci_dev.config;if (proxy-class_code) {pci_config_set_class(config, proxy-class_code);}if (legacy) {if (!virtio_legacy_allowed(vdev)) {/** To avoid migration issues, we allow legacy mode when legacy* check is disabled in the old machine types ( 5.1).*/if (virtio_legacy_check_disabled(vdev)) {warn_report(device is modern-only, but for backward compatibility legacy is allowed);} else {error_setg(errp,device is modern-only, use disable-legacyon);return;}}if (virtio_host_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM)) {error_setg(errp, VIRTIO_F_IOMMU_PLATFORM was supported by neither legacy nor transitional device);return;}/** Legacy and transitional devices use specific subsystem IDs.* Note that the subsystem vendor ID (config PCI_SUBSYSTEM_VENDOR_ID)* is set to PCI_SUBVENDOR_ID_REDHAT_QUMRANET by default.*/pci_set_word(config PCI_SUBSYSTEM_ID, virtio_bus_get_vdev_id(bus));if (proxy-trans_devid) {pci_config_set_device_id(config, proxy-trans_devid);}} else {/* pure virtio-1.0 */pci_set_word(config PCI_VENDOR_ID,PCI_VENDOR_ID_REDHAT_QUMRANET);pci_set_word(config PCI_DEVICE_ID,PCI_DEVICE_ID_VIRTIO_10_BASE virtio_bus_get_vdev_id(bus));pci_config_set_revision(config, 1);}config[PCI_INTERRUPT_PIN] 1;if (modern) {struct virtio_pci_cap cap {.cap_len sizeof cap,};struct virtio_pci_notify_cap notify {.cap.cap_len sizeof notify,.notify_off_multiplier cpu_to_le32(virtio_pci_queue_mem_mult(proxy)),};struct virtio_pci_cfg_cap cfg {.cap.cap_len sizeof cfg,.cap.cfg_type VIRTIO_PCI_CAP_PCI_CFG,};struct virtio_pci_notify_cap notify_pio {.cap.cap_len sizeof notify,.notify_off_multiplier cpu_to_le32(0x0),};struct virtio_pci_cfg_cap *cfg_mask;virtio_pci_modern_regions_init(proxy, vdev-name);virtio_pci_modern_mem_region_map(proxy, proxy-common, cap);virtio_pci_modern_mem_region_map(proxy, proxy-isr, cap);virtio_pci_modern_mem_region_map(proxy, proxy-device, cap);virtio_pci_modern_mem_region_map(proxy, proxy-notify, notify.cap);if (modern_pio) {memory_region_init(proxy-io_bar, OBJECT(proxy),virtio-pci-io, 0x4);pci_register_bar(proxy-pci_dev, proxy-modern_io_bar_idx,PCI_BASE_ADDRESS_SPACE_IO, proxy-io_bar);virtio_pci_modern_io_region_map(proxy, proxy-notify_pio,notify_pio.cap);}pci_register_bar(proxy-pci_dev, proxy-modern_mem_bar_idx,PCI_BASE_ADDRESS_SPACE_MEMORY |PCI_BASE_ADDRESS_MEM_PREFETCH |PCI_BASE_ADDRESS_MEM_TYPE_64,proxy-modern_bar);proxy-config_cap virtio_pci_add_mem_cap(proxy, cfg.cap);cfg_mask (void *)(proxy-pci_dev.wmask proxy-config_cap);pci_set_byte(cfg_mask-cap.bar, ~0x0);pci_set_long((uint8_t *)cfg_mask-cap.offset, ~0x0);pci_set_long((uint8_t *)cfg_mask-cap.length, ~0x0);pci_set_long(cfg_mask-pci_cfg_data, ~0x0);}if (proxy-nvectors) {int err msix_init_exclusive_bar(proxy-pci_dev, proxy-nvectors,proxy-msix_bar_idx, NULL);if (err) {/* Notice when a system that supports MSIx cant initialize it */if (err ! -ENOTSUP) {warn_report(unable to init msix vectors to % PRIu32,proxy-nvectors);}proxy-nvectors 0;}}proxy-pci_dev.config_write virtio_write_config;proxy-pci_dev.config_read virtio_read_config;if (legacy) {size VIRTIO_PCI_REGION_SIZE(proxy-pci_dev) virtio_bus_get_vdev_config_len(bus);size pow2ceil(size);memory_region_init_io(proxy-bar, OBJECT(proxy),virtio_pci_config_ops,proxy, virtio-pci, size);pci_register_bar(proxy-pci_dev, proxy-legacy_io_bar_idx,PCI_BASE_ADDRESS_SPACE_IO, proxy-bar);}
}可以看到virtio_pci_device_plugged函数比较长在笔者选用的qemu-8.1.3版本的源码中有160行左右。
对于virtio_pci_device_plugged函数的详细解析请看下回。
