1// Copyright 2018 The Fuchsia Authors
2//
3// Use of this source code is governed by a MIT-style
4// license that can be found in the LICENSE file or at
5// https://opensource.org/licenses/MIT
6
7#pragma once
8
9#include <hypervisor/guest_physical_address_space.h>
10#include <zircon/types.h>
11
12struct PvClockState;
13
14// This structure contains mapping between TSC and host wall time at some point
15// in time. KVM has a hypercall that asks the VMM to populate this structure and
16// it's actually used, which is rather puzzling considering that PV clock
17// provides an API to get wall time at the time of boot and offset from that time
18// which seem to be enough.
19//
20// More detailed description of KVM API is available here:
21//  https://www.kernel.org/doc/Documentation/virtual/kvm/hypercalls.txt
22struct PvClockOffset {
23    uint64_t sec;
24    uint64_t nsec;
25    uint64_t tsc;
26    uint32_t flags;
27    uint32_t unused[9];
28} __PACKED;
29
30// Updates guest boot time.
31zx_status_t pvclock_update_boot_time(hypervisor::GuestPhysicalAddressSpace* gpas,
32                                     zx_vaddr_t guest_paddr);
33
34// Remembers guest physical address for KVM clock system time structure and enables updates
35// to guest system time.
36zx_status_t pvclock_reset_clock(PvClockState* pvclock, hypervisor::GuestPhysicalAddressSpace* gpas,
37                                zx_vaddr_t guest_paddr);
38
39// Disables updates to guest system time.
40void pvclock_stop_clock(PvClockState* pvclock);
41
42// Updates guest system time. If updates disabled does nothing.
43void pvclock_update_system_time(PvClockState* pvclock, hypervisor::GuestPhysicalAddressSpace* gpas);
44
45// Populates mapping between TSC and wall time per guest request. guest_padds contains
46// physical address of PvClockOffset structure where the result should be stored.
47zx_status_t pvclock_populate_offset(hypervisor::GuestPhysicalAddressSpace* gpas,
48                                    zx_vaddr_t guest_paddr);
49