To enable it, you need to set -accel kvm,x-precise-tsc=on,
and have a kernel that supports this feature.
Signed-off-by: Maxim Levitsky <mlevitsk@xxxxxxxxxx>
---
accel/kvm/kvm-all.c | 28 +++++++++
include/sysemu/kvm.h | 1 +
target/i386/cpu.h | 1 +
target/i386/kvm.c | 140 +++++++++++++++++++++++++++++++++---------
target/i386/machine.c | 19 ++++++
5 files changed, 161 insertions(+), 28 deletions(-)
diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index baaa54249d..3829f2e7a3 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -104,6 +104,8 @@ struct KVMState
OnOffAuto kernel_irqchip_split;
bool sync_mmu;
uint64_t manual_dirty_log_protect;
+ /* Use KVM_GET_TSC_PRECISE/KVM_SET_TSC_PRECISE to access IA32_TSC */
+ bool precise_tsc;
/* The man page (and posix) say ioctl numbers are signed int, but
* they're not. Linux, glibc and *BSD all treat ioctl numbers as
* unsigned, and treating them as signed here can break things */
@@ -3194,6 +3196,24 @@ bool kvm_kernel_irqchip_split(void)
return kvm_state->kernel_irqchip_split == ON_OFF_AUTO_ON;
}
+bool kvm_has_precise_tsc(void)
+{
+ return kvm_state && kvm_state->precise_tsc;
+}
+
+static void kvm_set_precise_tsc(Object *obj,
+ bool value, Error **errp G_GNUC_UNUSED)
+{
+ KVMState *s = KVM_STATE(obj);
+ s->precise_tsc = value;
+}
+
+static bool kvm_get_precise_tsc(Object *obj, Error **errp G_GNUC_UNUSED)
+{
+ KVMState *s = KVM_STATE(obj);
+ return s->precise_tsc;
+}
+
static void kvm_accel_instance_init(Object *obj)
{
KVMState *s = KVM_STATE(obj);
@@ -3222,6 +3242,14 @@ static void kvm_accel_class_init(ObjectClass *oc, void *data)
NULL, NULL);
object_class_property_set_description(oc, "kvm-shadow-mem",
"KVM shadow MMU size");
+
+ object_class_property_add_bool(oc, "x-precise-tsc",
+ kvm_get_precise_tsc,
+ kvm_set_precise_tsc);
+
+ object_class_property_set_description(oc, "x-precise-tsc",
+ "Use precise tsc kvm API");
+
}
static const TypeInfo kvm_accel_type = {
diff --git a/include/sysemu/kvm.h b/include/sysemu/kvm.h
index bb5d5cf497..14eff2b1c9 100644
--- a/include/sysemu/kvm.h
+++ b/include/sysemu/kvm.h
@@ -519,6 +519,7 @@ void kvm_init_irq_routing(KVMState *s);
bool kvm_kernel_irqchip_allowed(void);
bool kvm_kernel_irqchip_required(void);
bool kvm_kernel_irqchip_split(void);
+bool kvm_has_precise_tsc(void);
/**
* kvm_arch_irqchip_create:
diff --git a/target/i386/cpu.h b/target/i386/cpu.h
index 88e8586f8f..d2230d9735 100644
--- a/target/i386/cpu.h
+++ b/target/i386/cpu.h
@@ -1460,6 +1460,7 @@ typedef struct CPUX86State {
uint64_t tsc_adjust;
uint64_t tsc_deadline;
uint64_t tsc_aux;
+ uint64_t tsc_ns_timestamp;
uint64_t xcr0;
diff --git a/target/i386/kvm.c b/target/i386/kvm.c
index a2934dda02..4adb7d6246 100644
--- a/target/i386/kvm.c
+++ b/target/i386/kvm.c
@@ -121,7 +121,6 @@ static int has_xsave;
static int has_xcrs;
static int has_pit_state2;
static int has_exception_payload;
-
static bool has_msr_mcg_ext_ctl;
static struct kvm_cpuid2 *cpuid_cache;
@@ -196,31 +195,112 @@ static int kvm_get_tsc(CPUState *cs)
{
X86CPU *cpu = X86_CPU(cs);
CPUX86State *env = &cpu->env;
- struct {
- struct kvm_msrs info;
- struct kvm_msr_entry entries[1];
- } msr_data = {};
int ret;
if (env->tsc_valid) {
return 0;
}
- memset(&msr_data, 0, sizeof(msr_data));
- msr_data.info.nmsrs = 1;
- msr_data.entries[0].index = MSR_IA32_TSC;
- env->tsc_valid = !runstate_is_running();
+ if (kvm_has_precise_tsc()) {
+ struct kvm_tsc_state tsc_state;
- ret = kvm_vcpu_ioctl(CPU(cpu), KVM_GET_MSRS, &msr_data);
- if (ret < 0) {
- return ret;
+ ret = kvm_vcpu_ioctl(CPU(cpu), KVM_GET_TSC_STATE, &tsc_state);
+ if (ret < 0) {
+ return ret;
+ }
+
+ env->tsc = tsc_state.tsc;
+
+ if (tsc_state.flags & KVM_TSC_STATE_TIMESTAMP_VALID) {
+ env->tsc_ns_timestamp = tsc_state.nsec;
+ }
+
+ if (tsc_state.flags & KVM_TSC_STATE_TSC_ADJUST_VALID) {
+ env->tsc_adjust = tsc_state.tsc_adjust;
+ }
+
+ } else {
+ struct {
+ struct kvm_msrs info;
+ struct kvm_msr_entry entries[2];
+ } msr_data = {
+ .info.nmsrs = 1,
+ .entries[0].index = MSR_IA32_TSC,
+ };
+
+ if (has_msr_tsc_adjust) {
+ msr_data.info.nmsrs++;
+ msr_data.entries[1].index = MSR_TSC_ADJUST;
+ }
+
+ ret = kvm_vcpu_ioctl(CPU(cpu), KVM_GET_MSRS, &msr_data);
+ if (ret < 0) {
+ return ret;
+ }
+
+ assert(ret == msr_data.info.nmsrs);
+ env->tsc = msr_data.entries[0].data;
+ if (has_msr_tsc_adjust) {
+ env->tsc_adjust = msr_data.entries[1].data;
+ }
}
- assert(ret == 1);
- env->tsc = msr_data.entries[0].data;
+ env->tsc_valid = !runstate_is_running();
return 0;
}
+static int kvm_set_tsc(CPUState *cs)
+{
+ int ret;
+ X86CPU *cpu = X86_CPU(cs);
+ CPUX86State *env = &cpu->env;
+
+ if (kvm_has_precise_tsc()) {
+ struct kvm_tsc_state tsc_state = {
+ .tsc = env->tsc,
+ };
+
+ if (env->tsc_ns_timestamp) {
+ tsc_state.nsec = env->tsc_ns_timestamp;
+ tsc_state.flags |= KVM_TSC_STATE_TIMESTAMP_VALID;
+ }
+
+ if (has_msr_tsc_adjust) {
+ tsc_state.tsc_adjust = env->tsc_adjust;
+ tsc_state.flags |= KVM_TSC_STATE_TSC_ADJUST_VALID;
+ }
+
+ ret = kvm_vcpu_ioctl(CPU(cpu), KVM_SET_TSC_STATE, &tsc_state);
+ if (ret < 0) {
+ return ret;
+ }
+
+ } else {
+ struct {
+ struct kvm_msrs info;
+ struct kvm_msr_entry entries[2];
+ } msr_data = {
+ .info.nmsrs = 1,
+ .entries[0].index = MSR_IA32_TSC,
+ .entries[0].data = env->tsc,
+ };
+
+ if (has_msr_tsc_adjust) {
+ msr_data.info.nmsrs++;
+ msr_data.entries[1].index = MSR_TSC_ADJUST;
+ msr_data.entries[1].data = env->tsc_adjust;
+ }
+
+ ret = kvm_vcpu_ioctl(CPU(cpu), KVM_SET_MSRS, &msr_data);
+ if (ret < 0) {
+ return ret;
+ }
+
+ assert(ret == msr_data.info.nmsrs);
+ }
+ return ret;
+}
+
static inline void do_kvm_synchronize_tsc(CPUState *cpu, run_on_cpu_data arg)
{
kvm_get_tsc(cpu);
@@ -1780,6 +1860,13 @@ int kvm_arch_init_vcpu(CPUState *cs)
}
}
+ if (kvm_has_precise_tsc()) {
+ if (!kvm_check_extension(cs->kvm_state, KVM_CAP_PRECISE_TSC)) {
+ error_report("kvm: Precise TSC is not supported by the host's KVM");
+ return -ENOTSUP;
+ }
+ }
+
if (cpu->vmware_cpuid_freq
/* Guests depend on 0x40000000 to detect this feature, so only expose
* it if KVM exposes leaf 0x40000000. (Conflicts with Hyper-V) */
@@ -2756,9 +2843,6 @@ static int kvm_put_msrs(X86CPU *cpu, int level)
if (has_msr_tsc_aux) {
kvm_msr_entry_add(cpu, MSR_TSC_AUX, env->tsc_aux);
}
- if (has_msr_tsc_adjust) {
- kvm_msr_entry_add(cpu, MSR_TSC_ADJUST, env->tsc_adjust);
- }
if (has_msr_misc_enable) {
kvm_msr_entry_add(cpu, MSR_IA32_MISC_ENABLE,
env->msr_ia32_misc_enable);
@@ -2802,7 +2886,6 @@ static int kvm_put_msrs(X86CPU *cpu, int level)
* for normal writeback. Limit them to reset or full state updates.
*/
if (level >= KVM_PUT_RESET_STATE) {
- kvm_msr_entry_add(cpu, MSR_IA32_TSC, env->tsc);
kvm_msr_entry_add(cpu, MSR_KVM_SYSTEM_TIME, env->system_time_msr);
kvm_msr_entry_add(cpu, MSR_KVM_WALL_CLOCK, env->wall_clock_msr);
if (env->features[FEAT_KVM] & (1 << KVM_FEATURE_ASYNC_PF_INT)) {
@@ -3142,9 +3225,6 @@ static int kvm_get_msrs(X86CPU *cpu)
if (has_msr_tsc_aux) {
kvm_msr_entry_add(cpu, MSR_TSC_AUX, 0);
}
- if (has_msr_tsc_adjust) {
- kvm_msr_entry_add(cpu, MSR_TSC_ADJUST, 0);
- }
if (has_msr_tsc_deadline) {
kvm_msr_entry_add(cpu, MSR_IA32_TSCDEADLINE, 0);
}
@@ -3178,10 +3258,6 @@ static int kvm_get_msrs(X86CPU *cpu)
if (has_msr_virt_ssbd) {
kvm_msr_entry_add(cpu, MSR_VIRT_SSBD, 0);
}
- if (!env->tsc_valid) {
- kvm_msr_entry_add(cpu, MSR_IA32_TSC, 0);
- env->tsc_valid = !runstate_is_running();
- }
#ifdef TARGET_X86_64
if (lm_capable_kernel) {
@@ -3385,9 +3461,6 @@ static int kvm_get_msrs(X86CPU *cpu)
case MSR_TSC_AUX:
env->tsc_aux = msrs[i].data;
break;
- case MSR_TSC_ADJUST:
- env->tsc_adjust = msrs[i].data;
- break;
case MSR_IA32_TSCDEADLINE:
env->tsc_deadline = msrs[i].data;
break;
@@ -3995,6 +4068,11 @@ int kvm_arch_put_registers(CPUState *cpu, int level)
if (ret < 0) {
return ret;
}
+
+ ret = kvm_set_tsc(cpu);
+ if (ret < 0) {
+ return ret;
+ }
}
ret = kvm_put_tscdeadline_msr(x86_cpu);
@@ -4064,6 +4142,12 @@ int kvm_arch_get_registers(CPUState *cs)
if (ret < 0) {
goto out;
}
+
+ ret = kvm_get_tsc(cs);
+ if (ret < 0) {
+ goto out;
+ }
+
ret = 0;
out:
cpu_sync_bndcs_hflags(&cpu->env);
diff --git a/target/i386/machine.c b/target/i386/machine.c
index 233e46bb70..59b1c9be2b 100644
--- a/target/i386/machine.c
+++ b/target/i386/machine.c
@@ -1359,6 +1359,24 @@ static const VMStateDescription vmstate_msr_tsx_ctrl = {
}
};
+
+static bool tsc_ns_timestamp_needed(void *opaque)
+{
+ return kvm_has_precise_tsc();
+}
+
+static const VMStateDescription vmstate_tsc_ns_timestamp = {
+ .name = "cpu/tsc_ns_timestamp",
+ .version_id = 1,
+ .minimum_version_id = 1,
+ .needed = tsc_ns_timestamp_needed,
+ .fields = (VMStateField[]) {
+ VMSTATE_UINT64(env.tsc_ns_timestamp, X86CPU),
+ VMSTATE_END_OF_LIST()
+ }
+};
+
+
VMStateDescription vmstate_x86_cpu = {
.name = "cpu",
.version_id = 12,
@@ -1493,6 +1511,7 @@ VMStateDescription vmstate_x86_cpu = {
#endif
#ifdef CONFIG_KVM
&vmstate_nested_state,
+ &vmstate_tsc_ns_timestamp,
#endif
&vmstate_msr_tsx_ctrl,
NULL
--
2.26.2
