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1fc6d50f3e
This can be uses to indicate to the caller that it should wait on the barrier before returning as there is some asynchronous activity triggered by the write which requires the KVM exit to block until it's completed. This is useful for having vCPU thread wait for the VMM thread to proceed to activate the virtio devices. See #1863 Signed-off-by: Rob Bradford <robert.bradford@intel.com>
46 lines
1.6 KiB
Rust
46 lines
1.6 KiB
Rust
// Copyright 2017 The Chromium OS Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE-BSD-3-Clause file.
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use std::sync::{Arc, Barrier};
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use vm_device::BusDevice;
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use vmm_sys_util::eventfd::EventFd;
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/// A i8042 PS/2 controller that emulates just enough to shutdown the machine.
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pub struct I8042Device {
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reset_evt: EventFd,
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}
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impl I8042Device {
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/// Constructs a i8042 device that will signal the given event when the guest requests it.
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pub fn new(reset_evt: EventFd) -> I8042Device {
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I8042Device { reset_evt }
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}
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}
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// i8042 device is located at I/O port 0x61. We partially implement two 8-bit
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// registers: port 0x61 (I8042_PORT_B_REG, offset 0 from base of 0x61), and
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// port 0x64 (I8042_COMMAND_REG, offset 3 from base of 0x61).
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impl BusDevice for I8042Device {
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fn read(&mut self, _base: u64, offset: u64, data: &mut [u8]) {
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if data.len() == 1 && offset == 3 {
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data[0] = 0x0;
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} else if data.len() == 1 && offset == 0 {
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// Like kvmtool, we return bit 5 set in I8042_PORT_B_REG to
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// avoid hang in pit_calibrate_tsc() in Linux kernel.
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data[0] = 0x20;
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}
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}
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fn write(&mut self, _base: u64, offset: u64, data: &[u8]) -> Option<Arc<Barrier>> {
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if data.len() == 1 && data[0] == 0xfe && offset == 3 {
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debug!("i8042 reset signalled");
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if let Err(e) = self.reset_evt.write(1) {
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error!("Error triggering i8042 reset event: {}", e);
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}
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}
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None
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}
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}
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