hv_read_config_block(9)

hv_read_config_block(9) 💖

okay so this page is from the Kernel API Manual, and the main character is hv_read_config_block(9). no cap, it has one iconic job: it sends a read config block request to the back-end driver running in the Hyper-V parent partition. periodt. 🦋

✨ NAME ✨

hv_read_config_block — sends a read config block request to the back-end driver running in the Hyper-V parent partition. 💅

🌸 SYNOPSIS 🌸

int hv_read_config_block (struct pci_dev *pdev , void *buf , unsigned
       int len , unsigned int block_id , unsigned int *bytes_returned );

🎀 ARGUMENTS 🎀

• pdev — the PCI driver’s representation for this device. literally the device’s little ID card. 🪪
• buf — the buffer into which the config block will be copied. it’s giving “drop the data right here.” 🫶
• len — size in bytes of buf. yes bestie, we need to know how much room we have. 💖
• block_id — identifies the config block which has been requested. iykyk. 🔥
• bytes_returned — size which came back from the back-end driver. the receipts, basically. 🧾

💜 RETURN 💜

0 on success, -errno on failure. slay when it works, sad little error vibe when it doesn’t. 😭

🌈 SEE ALSO 🌈

Kernel file ./drivers/pci/controller/pci-hyperv.c is the home base, and the whole squad is:

• struct hv_msi_desc(9)
• struct hv_msi_desc2(9)
• struct tran_int_desc(9)
• hv_irq_retarget_interrupt(9)
• hv_pci_generic_compl(9)
• devfn_to_wslot(9)
• wslot_to_devfn(9)
• _hv_pcifront_read_config(9)
• _hv_pcifront_write_config(9)
• hv_pcifront_read_config(9)
• hv_pcifront_write_config(9)
• hv_pci_read_config_compl(9)
• hv_pci_write_config_compl(9)
• hv_write_config_block(9)
• hv_register_block_invalidate(9)
• hv_msi_free(9)
• hv_compose_msi_msg(9)
• hv_pcie_init_irq_domain(9)
• get_bar_size(9)
• survey_child_resources(9)
• prepopulate_bars(9)
• create_root_hv_pci_bus(9)
• q_resource_requirements(9)
• new_pcichild_device(9)
• get_pcichild_wslot(9)
• pci_devices_present_work(9)
• hv_pci_start_relations_work(9)
• hv_pci_devices_present(9)
• hv_pci_devices_present2(9)
• hv_eject_device_work(9)
• hv_pci_eject_device(9)
• hv_pci_onchannelcallback(9)
• hv_pci_protocol_negotiation(9)
• hv_pci_free_bridge_windows(9)
• hv_pci_allocate_bridge_windows(9)
• hv_allocate_config_window(9)
• hv_pci_enter_d0(9)
• hv_pci_query_relations(9)
• hv_send_resources_allocated(9)
• hv_send_resources_released(9)
• hv_pci_probe(9)
• hv_pci_remove(9)

okay that’s the whole page, bestie. mwah 💋 — source/version vibe is ./drivers/pci/controller, dated October 2026, all about hv_read_config_block(9). 🫶✨