pci_epf_alloc_space(9)

📦 version 7.3.1, in nixpkgs unstable

✨ pci_epf_alloc_space(9) ✨

Okay so bestie, welcome to the Kernel API Manual entry for pci_epf_alloc_space — this is the function that grabs you some memory for the PCI EPF register space. Yes it's a real kernel function, no it's not scary, we're gonna get through it together 💖

🌸 NAME 🌸

pci_epf_alloc_space — allocate memory for the PCI EPF register space

Like, that's literally the whole vibe. You want register space memory? This is the girl handing it out. 🎀

⭐ SYNOPSIS ⭐

void * pci_epf_alloc_space (struct pci_epf *epf , size_t size , enum
pci_barno bar , const struct pci_epc_features *epc_features , enum
pci_epc_interface_type type );

Five arguments, one pointer back, and a whole lotta PCI going on. Not me counting the params three times 😭

🦋 ARGUMENTS 🦋

  • epf — the EPF device that's getting the memory. Like, the actual main character receiving the allocation. Slay 💅
  • size — how much memory you're asking for, in bytes. Respectfully, the whole point of the call.
  • bar — the BAR number that goes with the register space you just allocated. It's an enum pci_barno, so know your number, bestie ✨
  • epc_features — the features that the EPC provides, specifically for this EPF. Lowkey the personality check of the operation.
  • type — tells you whether the allocation is for the primary EPC or the secondary EPC. Two EPCs, two vibes, pick one 🫶

🔥 DESCRIPTION 🔥

Invoke this when you need to allocate memory for the PCI EPF register space. That's the assignment, and it ate. 👑

Now here's the fun part (iykyk): the flag PCI_BASE_ADDRESS_MEM_TYPE_64 will automatically get set if either of these is true:

  • the BAR can only be a 64-bit BAR, or
  • the requested size is larger than 2 GB

So you don't even have to think about it — the function clocked it and handled it for you. Not me being obsessed with automatic flag setting 💀✨

🌈 SEE ALSO 🌈

Kernel file ./drivers/pci/endpoint/pci-epf-core.c — and like, the whole friend group:

Go read all of them, bestie. Group chat's waiting 🧚💜

Alright, signing off! This little page lives in the kernel source tree at ./drivers/pci/endpoint, dated October 2026, and it's filed under pci_epf_alloc_space(9) — literally iconic, no cap 💖🦋🌸

📦 where this page comes from