syntax = "proto3";

// The protocol defined here is actually two sub-protocols, one protocol for control of the main
// process (MainRequest/MainResponse), and one for control of each VCPU thread
// (VcpuRequest/VcpuResponse). Each protocol works the same: the client creates a protobuf of either
// a MainRequest or VcpuRequest, sends it encoded over the main socket or one of the vcpu sockets,
// reads the the MainResponse or VcpuResponse over the same socket and decodes it as a protobuf. For
// specific information on the purpose of each request, see the C API in crosvm.h. Most requests
// here map 1:1 to a function in that API. Only the intricacies unique to the wire protocol are
// commented on here.

enum AddressSpace {
    IOPORT = 0;
    MMIO = 1;
 }

// A request made to the crosvm main process that affects the global aspects of the VM.
message MainRequest {
    // Every message under the Create namespace will instantiate an object with the given ID. The
    // type of object is determined by the oneof constructor field.
    message Create {
        message IoEvent {
            AddressSpace space = 1;
            uint64 address = 2;
            uint32 length = 3;
            uint64 datamatch = 4;
        }

        message Memory {
            uint64 offset = 1;
            uint64 start = 2;
            uint64 length = 3;
            bool read_only = 4;
        }

        message IrqEvent {
            uint32 irq_id = 1;
            bool resample = 2;
        }

        uint32 id = 1;
        oneof constructor {
            IoEvent io_event = 2;
            // This message also requires a memfd sent over the socket.
            Memory memory = 3;
            IrqEvent irq_event = 4;
        }
    }

    // No matter what the type an object is, it can be destroyed using this common method.
    message Destroy {
        uint32 id = 1;
    }

    message NewConnection {}

    message GetShutdownEventfd {}

    message ReserveRange {
        AddressSpace space = 1;
        uint64 start = 2;
        uint64 length = 3;
    }

    message SetIrq {
        uint32 irq_id = 1;
        bool active = 2;
    }

    message SetIrqRouting {
        message Route {
            message Irqchip {
                uint32 irqchip = 1;
                uint32 pin = 2;
            }

            message Msi {
                uint64 address = 1;
                uint32 data = 2;
            }

            uint32 irq_id = 1;
            oneof route {
                Irqchip irqchip = 2;
                Msi msi = 3;
            }
        }

        repeated Route routes = 1;
    }

    message SetIdentityMapAddr {
        uint32 address = 1;
    }

    message PauseVcpus {
        uint64 cpu_mask = 1;
        uint64 user = 2;
    }

    message GetVcpus {}
    message Start {}

    message MemoryDirtyLog {
        uint32 id = 1;
    }

    // The type of the message is determined by which of these oneof fields is present in the
    // protobuf.
    oneof message {
        // Common method for instantiating a new object of any type.
        Create create = 1;
        // Common method for destroying an object of any type.
        Destroy destroy = 2;
        NewConnection new_connection = 3;
        GetShutdownEventfd get_shutdown_eventfd = 4;
        ReserveRange reserve_range = 5;
        SetIrq set_irq = 6;
        SetIrqRouting set_irq_routing = 7;
        SetIdentityMapAddr set_identity_map_addr = 8;
        PauseVcpus pause_vcpus = 9;
        GetVcpus get_vcpus = 10;
        Start start = 11;
        // Method for a Memory type object for retrieving the dirty bitmap.
        MemoryDirtyLog dirty_log = 101;
    }
}

message MainResponse {
    // Depending on the object that was created, an fd might also come from the socket.
    message Create {}
    message Destroy {}
    // NewMessage receives a socket fd along with the data from reading this socket.
    // The returned socket can be used totally independently of the original socket, and can perform
    // requests and responses independent of the other sockets.
    message NewConnection {}
    message GetShutdownEventfd {}
    message ReserveRange {}
    message SetIrq {}
    message SetIrqRouting {}
    message SetIdentityMapAddr {}
    message PauseVcpus {}
    // This message should also receive a socket fd per VCPU along with the data from reading this
    // socket. The VcpuRequest/VcpuResponse protocol is run over each of the returned fds.
    message GetVcpus {}
    message Start {}
    message MemoryDirtyLog {
        bytes bitmap = 1;
    }

    // This is zero on success, and a negative integer on failure.
    sint32 errno = 1;
    // The field present here is always the same as the one present in the corresponding
    // MainRequest.
    oneof message {
        Create create = 2;
        Destroy destroy = 3;
        NewConnection new_connection = 4;
        GetShutdownEventfd get_shutdown_eventfd = 5;
        ReserveRange reserve_range = 6;
        SetIrq set_irq = 7;
        SetIrqRouting set_irq_routing = 8;
        SetIdentityMapAddr set_identity_map_addr = 9;
        PauseVcpus pause_vcpus = 10;
        GetVcpus get_vcpus = 11;
        Start start = 12;
        MemoryDirtyLog dirty_log = 101;
    }
}

// A request made for a specific VCPU. These requests are sent over the sockets returned from the
// GetVcpu MainRequest.
message VcpuRequest {
    // This message will block until a non-empty response can be sent. The first response will
    // always be an Init wait reason.
    message Wait {
    }

    message Resume {
        // The data is only necessary for non-write (read) I/O accesses. In all other cases, data is
        // ignored.
        bytes data = 1;
    }

    // Each type refers to a set of KVM VCPU registers. The structure of the data corresponds to the
    // kvm structure.
    enum StateSet {
        // struct kvm_regs
        REGS = 0;
        // struct kvm_sregs
        SREGS = 1;
        // struct kvm_fpu
        FPU = 2;
    }

    message GetState {
        StateSet set = 1;
    }

    message SetState {
        StateSet set = 1;
        // The in memory representation of a struct kvm_regs, struct kvm_sregs, or struct kvm_fpu,
        // depending on the value of the StateSet.
        bytes state = 2;
    }

    // The type of the message is determined by which of these oneof fields is present in the
    // protobuf.
    oneof message {
        Wait wait = 1;
        Resume resume = 2;
        GetState get_state = 3;
        SetState set_state = 4;
    }
}


message VcpuResponse  {
    // Depending on the reason a VCPU has exited, the Wait request will unblock and return a field
    // in the oneof exit. This is called the "wait reason."
    message Wait {
        // This request will always be the first wait reason returend by the first wait request.
        message Init {
        }

        // This type of wait reason is only generated if the access occurred on this VCPU on an
        // address previously reserved by a ReserveRange main request.
        message Io {
            AddressSpace space = 1;
            uint64 address = 2;
            bool is_write = 3;
            bytes data = 4;
        }

        // This type of wait reason is only generated after a PuaseVcpus request on this VCPU.
        message User {
            uint64 user = 1;
        }

        oneof exit {
            Init init = 1;
            Io io = 2;
            User user = 3;
        }
    }

    message Resume {}

    message GetState {
        // The in memory representation of a struct kvm_regs, struct kvm_sregs, or struct kvm_fpu,
        // depending on what StateSet was requested in GetState.
        bytes state = 1;
    }

    message SetState {
    }

    // This is zero on success, and a negative integer on failure.
    sint32 errno = 1;
    // The field present here is always the same as the one present in the corresponding
    // VcpuRequest.
    oneof message {
        Wait wait = 2;
        Resume resume = 3;
        GetState get_state = 4;
        SetState set_state = 5;
    }
}