epf_ntb_configure_mw(9)

✨ epf_ntb_configure_mw(9) ✨

okay bestie, welcome to the Kernel API Manual 🫶 this one's a function page — epf_ntb_configure_mw(9) — and it's lowkey the moment the Outbound Address Space gets set up so VHOST can reach into HOST's memory window. no cap, it's giving glue-code-that-actually-matters 💅

---

🌸 NAME 🌸

epf_ntb_configure_mw — Configure the Outbound Address Space so VHOST can access the memory window of HOST

---

⭐ SYNOPSIS ⭐

int epf_ntb_configure_mw (struct epf_ntb *ntb , u32 mw );

---

🎀 ARGUMENTS 🎀

• ntb — the NTB device that facilitates communication between HOST and VHOST. literally the whole reason this function exists, she's the main character 👑
• mw — the index of the memory window. and ngl it has to be one of these four: either 0, 1, 2 or 3. that's the whole range, periodt.

---

🦋 DESCRIPTION 🦋

okay so picture this: we're talking about the EP Outbound Window. here's the diagram, exactly as our ancestors drew it 🙈

┌───────────┐
│           │
│           │
│           │
│           │
└───────────┘
|        |              +-----------+ | Virtual|              | Memory
Win| | NTB    | -----------> |           | | Driver |              |
| |        |              +-----------+ |        |              |
| |        |              |           | VHOST                   PCI EP

like yes the ASCII art is fighting for its life 😭 but the vibe is: the Virtual Driver on VHOST reaches through the NTB memory window over to the PCI EP side. that's the outbound window flow, iykyk ✨

---

🔥 RETURN 🔥

Zero for success, or an error code in case of failure. so if you get 0 she ate 💖 and if you get anything else, something went sideways, no hard feelings 🌈

---

👑 SEE ALSO 👑

Kernel file ./drivers/pci/endpoint/functions/pci-epf-vntb.c — that's the source of truth bestie, go read her 📖

• epf_ntb_link_up(9)
• epf_ntb_teardown_mw(9)
• epf_ntb_cmd_handler(9)
• epf_ntb_config_sspad_bar_clear(9)
• epf_ntb_config_sspad_bar_set(9)
• epf_ntb_config_spad_bar_free(9)
• epf_ntb_config_spad_bar_alloc(9)
• epf_ntb_configure_interrupt(9)
• epf_ntb_db_bar_init(9)
• epf_ntb_db_bar_clear(9)
• epf_ntb_mw_bar_init(9)
• epf_ntb_mw_bar_clear(9)
• epf_ntb_is_bar_used(9)
• epf_ntb_find_bar(9)
• epf_ntb_init_epc_bar(9)
• epf_ntb_epc_init(9)
• epf_ntb_epc_cleanup(9)
• epf_ntb_add_cfs(9)
• epf_ntb_bind(9)
• epf_ntb_unbind(9)
• epf_ntb_probe(9)

---

and that's the page!! 💜 this little gem comes to you from ./drivers/pci/endpoint/functions, dated October 2026 — drink some water, go touch a memory window, ily bye 🎀🧚