hv_write_config_block(9)

🦋 hv_write_config_block — the Kernel API Manual moment

Okay bestie, so this is the page for hv_write_config_block(9), straight out of the Kernel API Manual, and it's lowkey one of those little plumbing functions that makes Hyper-V PCI passthrough work. The way that name is long — iconic. Let's get into it 💅

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✨ NAME ✨

hv_write_config_block — sends a write config block request to the backend driver running in the Hyper-V parent partition. That's it, that's the whole vibe: you're asking the parent partition to write a config block for you 🫶

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✨ SYNOPSIS ✨

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

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🎀 ARGUMENTS 🎀

• pdev — the PCI driver's representation for this device. Basically the device's little ID card 🪪
• buf — the buffer that the config block gets copied from. Your source material, bestie ✨
• len — the size in bytes of buf. Gotta tell it how much to take, no cap 🍓
• block_id — identifies which config block is being written. Like a lil name tag for the block 👑

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🔥 RETURN 🔥

0 on success, -errno on failure. Slay if it's zero, cry in errno if it isn't 😭

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🌈 SEE ALSO 🌈

The original points you at the kernel file ./drivers/pci/controller/pci-hyperv.c plus this whole friend group of symbols. Everyone's here, nobody's left out 👑

• 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_read_config_block(9)
• hv_pci_write_config_compl(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)

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That's the whole page, bestie — go read your config blocks and stay hydrated 💖

Sign-off era: this one's from the source/version <pink>./drivers/pci/controller</pink>, dated October 2026, and the page answers to hv_write_config_block(9). Periodt 🎀