diff options
Diffstat (limited to 'qemu/hw/i386/kvm/clock.c')
| -rw-r--r-- | qemu/hw/i386/kvm/clock.c | 209 |
1 files changed, 209 insertions, 0 deletions
diff --git a/qemu/hw/i386/kvm/clock.c b/qemu/hw/i386/kvm/clock.c new file mode 100644 index 000000000..efdf16584 --- /dev/null +++ b/qemu/hw/i386/kvm/clock.c @@ -0,0 +1,209 @@ +/* + * 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) |