Method allocate_bars

pci/src/vfio.rs:619–821

(
        &mut self,
        allocator: &mut SystemAllocator,
        mmio32_allocator: &mut AddressAllocator,
        mmio64_allocator: &mut AddressAllocator,
        resources: Option<&[Resource]>,

    // The `allocator` argument is unused on `aarch64`
    #[allow(unused_variables)]
    pub(crate) fn allocate_bars(
        &mut self,
        allocator: &mut SystemAllocator,
        mmio32_allocator: &mut AddressAllocator,
        mmio64_allocator: &mut AddressAllocator,
        resources: Option<&[Resource]>,
    ) -> Result<Vec<PciBarConfiguration>, PciDeviceError> {
        let mut bars = Vec::new();
        let mut bar_id = VFIO_PCI_BAR0_REGION_INDEX;

        // Going through all regular regions to compute the BAR size.
        // We're not saving the BAR address to restore it, because we
        // are going to allocate a guest address for each BAR and write
        // that new address back.
        while bar_id < VFIO_PCI_CONFIG_REGION_INDEX {
            let mut region_size: u64 = 0;
            let mut region_type = PciBarRegionType::Memory32BitRegion;
            let mut prefetchable = PciBarPrefetchable::NotPrefetchable;
            let mut flags: u32 = 0;

            let mut restored_bar_addr = None;
            if let Some(resources) = resources {
                for resource in resources {
                    if let Resource::PciBar {
                        index,
                        base,
                        size,
                        type_,
                        ..
                    } = resource
                        && *index == bar_id as usize
                    {
                        restored_bar_addr = Some(GuestAddress(*base));
                        region_size = *size;
                        region_type = PciBarRegionType::from(*type_);
                        break;
                    }
                }
                if restored_bar_addr.is_none() {
                    bar_id += 1;
                    continue;
                }
            } else {
                let bar_offset = if bar_id == VFIO_PCI_ROM_REGION_INDEX {
                    (PCI_ROM_EXP_BAR_INDEX * 4) as u32
                } else {
                    PCI_CONFIG_BAR_OFFSET + bar_id * 4
                };

                // First read flags
                flags = self.vfio_wrapper.read_config_dword(bar_offset);

                // Is this an IO BAR?
                let io_bar = if bar_id == VFIO_PCI_ROM_REGION_INDEX {
                    false
                } else {
                    matches!(flags & PCI_CONFIG_IO_BAR, PCI_CONFIG_IO_BAR)
                };