Method make_routing_entry

hypervisor/src/kvm/mod.rs:922–974

Constructs a routing entry

(&self, gsi: u32, config: &InterruptSourceConfig)

    /// Constructs a routing entry
    ///
    fn make_routing_entry(&self, gsi: u32, config: &InterruptSourceConfig) -> IrqRoutingEntry {
        match &config {
            InterruptSourceConfig::MsiIrq(cfg) => {
                let mut kvm_route = kvm_irq_routing_entry {
                    gsi,
                    type_: KVM_IRQ_ROUTING_MSI,
                    ..Default::default()
                };

                let (address_lo, address_hi) =
                    Self::translate_msi_ext_dest_id(cfg.low_addr, cfg.high_addr);

                kvm_route.u.msi.address_lo = address_lo;
                kvm_route.u.msi.address_hi = address_hi;

                kvm_route.u.msi.data = cfg.data;

                if self.check_extension(crate::kvm::Cap::MsiDevid) {
                    // On AArch64, there is limitation on the range of the 'devid',
                    // it cannot be greater than 65536 (the max of u16).
                    //
                    // BDF cannot be used directly, because 'segment' is in high
                    // 16 bits. The layout of the u32 BDF is:
                    // |---- 16 bits ----|-- 8 bits --|-- 5 bits --|-- 3 bits --|
                    // |      segment    |     bus    |   device   |  function  |
                    //
                    // Now that we support 1 bus only in a segment, we can build a
                    // 'devid' by replacing the 'bus' bits with the low 8 bits of
                    // 'segment' data.
                    // This way we can resolve the range checking problem and give
                    // different `devid` to all the devices. Limitation is that at
                    // most 256 segments can be supported.
                    //
                    let modified_devid = ((cfg.devid & 0x00ff_0000) >> 8) | cfg.devid & 0xff;

                    kvm_route.flags = KVM_MSI_VALID_DEVID;
                    kvm_route.u.msi.__bindgen_anon_1.devid = modified_devid;
                }
                kvm_route.into()
            }
            InterruptSourceConfig::LegacyIrq(cfg) => {
                let mut kvm_route = kvm_irq_routing_entry {
                    gsi,
                    type_: KVM_IRQ_ROUTING_IRQCHIP,
                    ..Default::default()
                };
                kvm_route.u.irqchip.irqchip = cfg.irqchip;
                kvm_route.u.irqchip.pin = cfg.pin;

                kvm_route.into()
            }
        }
    }

    ///
    /// Sets the GSI routing table entries, overwriting any previously set