Method start_addr

vmm/src/memory_manager.rs:2139–2156

Calculate the start address of an area next to RAM. If memory hotplug is allowed, the start address needs to be aligned (rounded-up) to 128MiB boundary. If memory hotplug is not allowed, there is no alignment required. And it must also start at the 64bit start.

(mem_end: GuestAddress, allow_mem_hotplug: bool)

    // If memory hotplug is not allowed, there is no alignment required.
    // And it must also start at the 64bit start.
    fn start_addr(mem_end: GuestAddress, allow_mem_hotplug: bool) -> Result<GuestAddress, Error> {
        let mut start_addr = if allow_mem_hotplug {
            GuestAddress(mem_end.0 | ((128 << 20) - 1))
        } else {
            mem_end
        };

        start_addr = start_addr
            .checked_add(1)
            .ok_or(Error::GuestAddressOverFlow)?;

        #[cfg(not(target_arch = "riscv64"))]
        if mem_end < arch::layout::MEM_32BIT_RESERVED_START {
            return Ok(arch::layout::RAM_64BIT_START);
        }

        Ok(start_addr)
    }

    pub fn add_ram_region(
        &mut self,