Now, running make run/virtualbox has some progress, and QEMU is started. But I don't get anything on QEMU (except the description of NOVA), and I got the following in the terminal:

Genode 15.05
int main(): --- create local services ---
int main(): --- start init ---
int main(): transferred 444 MB to init
Quota exceeded! amount=24576, size=4096, consumed=24576
[init] upgrading quota donation for Env::CPU (8192 bytes)
Quota exceeded! amount=32768, size=4096, consumed=32768
[init] upgrading quota donation for Env::CPU (8192 bytes)
[init -> acpi] available memory for ACPI 2048 kiB, for PCI_DRV 5468 kiB
[init -> acpi] void Acpi_table::_parse_tables(T*, Genode::uint32_t) [with T = unsigned int; Genode::uint32_t = unsigned int]: Found MADT
[init -> acpi] MADT IRQ 0 -> GSI 2 flags: 0
[init -> acpi] MADT IRQ 5 -> GSI 5 flags: d
[init -> acpi] MADT IRQ 9 -> GSI 9 flags: d
[init -> acpi] MADT IRQ 10 -> GSI 10 flags: d
[init -> acpi] MADT IRQ 11 -> GSI 11 flags: d
[init -> acpi] Could not open ROM session for module "config"
[init -> acpi] void* abort(): abort called
[init -> virtualbox] void init_libc_lock_pipe(): init_libc_lock_pipe()
[init -> virtualbox] using the pipe libc plugin
[init -> virtualbox] getenv called for non-existent variable "XML_MEM_BREAKPOINT"
[init -> virtualbox] getenv called for non-existent variable "XML_MEM_TRACE"
[init -> virtualbox] getenv called for non-existent variable "LC_ALL"
[init -> virtualbox] getenv called for non-existent variable "LC_CTYPE"
[init -> virtualbox] getenv called for non-existent variable "LANG"
[init -> virtualbox] getenv called for non-existent variable "PATH_LOCALE"
[init -> virtualbox] getenv called for non-existent variable "VBOX_DISABLE_HOST_DISK_CACHE"
[init -> virtualbox] getenv called for non-existent variable "CHARSETALIASDIR"
[init -> virtualbox] getenv called for non-existent variable "TZ"
[init -> virtualbox] int access(const char*, int): access not implemented
[init -> virtualbox] getenv called for non-existent variable "TZ"
[init -> virtualbox] fcntl(): command 2 not supported
[init -> virtualbox] Log created: 2015-07-10T06:05:00.621000000Z
[init -> virtualbox] main     Executable: /virtualbox
[init -> virtualbox] Could not open ROM session for module "usb_devices"
[init -> virtualbox] Could not retrieve the "usb_devices" ROM file.USB device pass-through unavailable.
[init -> virtualbox] SystemProperties : Cannot determine default Guest Additions ISO location. Most likely they are not available
int main(): --- init created, waiting for exit condition ---