--- /dev/null
+/*
+ * QEMU KVM support, paravirtual clock device
+ *
+ * Copyright (C) 2011 Siemens AG
+ *
+ * Authors:
+ * Jan Kiszka <jan.kiszka@siemens.com>
+ *
+ * This work is licensed under the terms of the GNU GPL version 2.
+ * See the COPYING file in the top-level directory.
+ *
+ * Contributions after 2012-01-13 are licensed under the terms of the
+ * GNU GPL, version 2 or (at your option) any later version.
+ */
+
+#include "qemu-common.h"
+#include "qemu/host-utils.h"
+#include "sysemu/sysemu.h"
+#include "sysemu/kvm.h"
+#include "sysemu/cpus.h"
+#include "hw/sysbus.h"
+#include "hw/kvm/clock.h"
+
+#include <linux/kvm.h>
+#include <linux/kvm_para.h>
+
+#define TYPE_KVM_CLOCK "kvmclock"
+#define KVM_CLOCK(obj) OBJECT_CHECK(KVMClockState, (obj), TYPE_KVM_CLOCK)
+
+typedef struct KVMClockState {
+ /*< private >*/
+ SysBusDevice busdev;
+ /*< public >*/
+
+ uint64_t clock;
+ bool clock_valid;
+} KVMClockState;
+
+struct pvclock_vcpu_time_info {
+ uint32_t version;
+ uint32_t pad0;
+ uint64_t tsc_timestamp;
+ uint64_t system_time;
+ uint32_t tsc_to_system_mul;
+ int8_t tsc_shift;
+ uint8_t flags;
+ uint8_t pad[2];
+} __attribute__((__packed__)); /* 32 bytes */
+
+static uint64_t kvmclock_current_nsec(KVMClockState *s)
+{
+ CPUState *cpu = first_cpu;
+ CPUX86State *env = cpu->env_ptr;
+ hwaddr kvmclock_struct_pa = env->system_time_msr & ~1ULL;
+ uint64_t migration_tsc = env->tsc;
+ struct pvclock_vcpu_time_info time;
+ uint64_t delta;
+ uint64_t nsec_lo;
+ uint64_t nsec_hi;
+ uint64_t nsec;
+
+ if (!(env->system_time_msr & 1ULL)) {
+ /* KVM clock not active */
+ return 0;
+ }
+
+ cpu_physical_memory_read(kvmclock_struct_pa, &time, sizeof(time));
+
+ assert(time.tsc_timestamp <= migration_tsc);
+ delta = migration_tsc - time.tsc_timestamp;
+ if (time.tsc_shift < 0) {
+ delta >>= -time.tsc_shift;
+ } else {
+ delta <<= time.tsc_shift;
+ }
+
+ mulu64(&nsec_lo, &nsec_hi, delta, time.tsc_to_system_mul);
+ nsec = (nsec_lo >> 32) | (nsec_hi << 32);
+ return nsec + time.system_time;
+}
+
+static void kvmclock_vm_state_change(void *opaque, int running,
+ RunState state)
+{
+ KVMClockState *s = opaque;
+ CPUState *cpu;
+ int cap_clock_ctrl = kvm_check_extension(kvm_state, KVM_CAP_KVMCLOCK_CTRL);
+ int ret;
+
+ if (running) {
+ struct kvm_clock_data data = {};
+ uint64_t time_at_migration = kvmclock_current_nsec(s);
+
+ s->clock_valid = false;
+
+ /* We can't rely on the migrated clock value, just discard it */
+ if (time_at_migration) {
+ s->clock = time_at_migration;
+ }
+
+ data.clock = s->clock;
+ ret = kvm_vm_ioctl(kvm_state, KVM_SET_CLOCK, &data);
+ if (ret < 0) {
+ fprintf(stderr, "KVM_SET_CLOCK failed: %s\n", strerror(ret));
+ abort();
+ }
+
+ if (!cap_clock_ctrl) {
+ return;
+ }
+ CPU_FOREACH(cpu) {
+ ret = kvm_vcpu_ioctl(cpu, KVM_KVMCLOCK_CTRL, 0);
+ if (ret) {
+ if (ret != -EINVAL) {
+ fprintf(stderr, "%s: %s\n", __func__, strerror(-ret));
+ }
+ return;
+ }
+ }
+ } else {
+ struct kvm_clock_data data;
+ int ret;
+
+ if (s->clock_valid) {
+ return;
+ }
+
+ cpu_synchronize_all_states();
+ /* In theory, the cpu_synchronize_all_states() call above wouldn't
+ * affect the rest of the code, as the VCPU state inside CPUState
+ * is supposed to always match the VCPU state on the kernel side.
+ *
+ * In practice, calling cpu_synchronize_state() too soon will load the
+ * kernel-side APIC state into X86CPU.apic_state too early, APIC state
+ * won't be reloaded later because CPUState.vcpu_dirty==true, and
+ * outdated APIC state may be migrated to another host.
+ *
+ * The real fix would be to make sure outdated APIC state is read
+ * from the kernel again when necessary. While this is not fixed, we
+ * need the cpu_clean_all_dirty() call below.
+ */
+ cpu_clean_all_dirty();
+
+ ret = kvm_vm_ioctl(kvm_state, KVM_GET_CLOCK, &data);
+ if (ret < 0) {
+ fprintf(stderr, "KVM_GET_CLOCK failed: %s\n", strerror(ret));
+ abort();
+ }
+ s->clock = data.clock;
+
+ /*
+ * If the VM is stopped, declare the clock state valid to
+ * avoid re-reading it on next vmsave (which would return
+ * a different value). Will be reset when the VM is continued.
+ */
+ s->clock_valid = true;
+ }
+}
+
+static void kvmclock_realize(DeviceState *dev, Error **errp)
+{
+ KVMClockState *s = KVM_CLOCK(dev);
+
+ qemu_add_vm_change_state_handler(kvmclock_vm_state_change, s);
+}
+
+static const VMStateDescription kvmclock_vmsd = {
+ .name = "kvmclock",
+ .version_id = 1,
+ .minimum_version_id = 1,
+ .fields = (VMStateField[]) {
+ VMSTATE_UINT64(clock, KVMClockState),
+ VMSTATE_END_OF_LIST()
+ }
+};
+
+static void kvmclock_class_init(ObjectClass *klass, void *data)
+{
+ DeviceClass *dc = DEVICE_CLASS(klass);
+
+ dc->realize = kvmclock_realize;
+ dc->vmsd = &kvmclock_vmsd;
+}
+
+static const TypeInfo kvmclock_info = {
+ .name = TYPE_KVM_CLOCK,
+ .parent = TYPE_SYS_BUS_DEVICE,
+ .instance_size = sizeof(KVMClockState),
+ .class_init = kvmclock_class_init,
+};
+
+/* Note: Must be called after VCPU initialization. */
+void kvmclock_create(void)
+{
+ X86CPU *cpu = X86_CPU(first_cpu);
+
+ if (kvm_enabled() &&
+ cpu->env.features[FEAT_KVM] & ((1ULL << KVM_FEATURE_CLOCKSOURCE) |
+ (1ULL << KVM_FEATURE_CLOCKSOURCE2))) {
+ sysbus_create_simple(TYPE_KVM_CLOCK, -1, NULL);
+ }
+}
+
+static void kvmclock_register_types(void)
+{
+ type_register_static(&kvmclock_info);
+}
+
+type_init(kvmclock_register_types)
Code Review / kvmfornfv.git / blobdiff