On Wed, Dec 07, 2022 at 10:02:53AM +0100, Philippe Mathieu-Daudé wrote: > On 7/12/22 07:25, Markus Armbruster wrote: > > pcie_sriov.h needs PCI_NUM_REGIONS from pci.h, but doesn't include it. > > pci.h must be included before pcie_sriov.h or else compile fails. > > > > Adding #include "pci/pci.h" to pcie_sriov would be wrong, because it > > would close an inclusion loop: pci.h includes pcie.h (for > > PCIExpressDevice) includes pcie_sriov.h (for PCIESriovPF) includes pci.h > > (for PCI_NUM_REGIONS). > > > > The obvious solution is to move PCI_NUM_REGIONS pci.h somewhere > > pcie_sriov.h can include without creating a loop. > > > > We already have a few headers that don't include anything: pci_ids.h, > > pci_regs.h (includes include/standard-headers/linux/pci_regs.h, which > > doesn't count), pcie_regs.h. Moving PCI_NUM_REGIONS to one of these > > would work, but it doesn't feel right. > > > > We could create a new one, say pci_defs.h. Just for PCI_NUM_REGIONS > > feels silly. So, what else should move there? > > Sounds good to me. Eventually name it pci_standard_defs.h?
standard is not a good name for PCI_NUM_REGIONS. It falls out of how QEMU represents things not directly out of the standard. QEMU supports up to 6 BAR registers + 1 expansion ROM. That's where the number comes from. Same with PCI_ROM_SLOT - that's a QEMU convention. > We can move the first 100 lines of pci.h there, PCI_ROM_SLOT, > PCI_NUM_REGIONS, PCI HEADER_TYPE, PCI_NUM_PINS, cap_present, and eventually > PCIINTxRoute & PCIReqIDType. It's a good point that PCI_ROM_SLOT should live with PCI_NUM_REGIONS. > > > > Any other ideas? > > > > In case you wonder why I bother you with this... > > > > Back in 2016, we discussed[1] rules for headers, and these were > > generally liked: > > > > 1. Have a carefully curated header that's included everywhere first. We > > got that already thanks to Peter: osdep.h. > > > > 2. Headers should normally include everything they need beyond osdep.h. > > If exceptions are needed for some reason, they must be documented in > > the header. If all that's needed from a header is typedefs, put > > those into qemu/typedefs.h instead of including the header. > > > > 3. Cyclic inclusion is forbidden. > > > > I'm working on patches to get include/ closer to obeying 2. > > > > [1] Message-ID: <87h9g8j57d....@blackfin.pond.sub.org> > > https://lists.nongnu.org/archive/html/qemu-devel/2016-03/msg03345.html > > > >