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// Copyright 2019 The Chromium OS Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
use sys_util::{GuestAddress, GuestMemory, MemoryMapping};
#[link(name = "rendernodehost")]
extern "C" {
fn start_render_node_host(
gpu_host_mem: *mut u8,
gpu_guest_mem_start: u64,
gpu_guest_mem_size: u64,
host_start: *const u8,
host_4g_start: *const u8,
);
}
/// The number of bytes in 4 GiB.
pub const FOUR_GB: u64 = (1 << 32);
/// The size required for the render node host in host and guest address space.
pub const RENDER_NODE_HOST_SIZE: u64 = FOUR_GB;
/// A render node host device that interfaces with the guest render node forwarder.
pub struct RenderNodeHost {
#[allow(dead_code)]
guest_mem: GuestMemory,
}
impl RenderNodeHost {
/// Starts the render node host forwarding service over the given guest and host address ranges.
pub fn start(
mmap: &MemoryMapping,
gpu_guest_address: u64,
guest_mem: GuestMemory,
) -> RenderNodeHost {
// Render node forward library need to do address translation between host user space
// address and guest physical address. We could call Rust function from C library. But
// since it's actually a linear mapping now, we just pass the host start address to
// render node forward library. We need two start address here since there would be a
// hole below 4G if guest memory size is bigger than 4G.
let host_start_addr = guest_mem.get_host_address(GuestAddress(0)).unwrap();
let host_4g_addr = if guest_mem.memory_size() > FOUR_GB {
guest_mem.get_host_address(GuestAddress(FOUR_GB)).unwrap()
} else {
host_start_addr
};
// Safe because only valid addresses are given.
unsafe {
start_render_node_host(
mmap.as_ptr(),
gpu_guest_address,
mmap.size() as u64,
host_start_addr,
host_4g_addr,
)
}
RenderNodeHost { guest_mem }
}
}
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