Reduce the number of mfTB executed by passing the current timebase
around entry and exit code rather than read it multiple times.
-213 cycles (7578) POWER9 virt-mode NULL hcall
Signed-off-by: Nicholas Piggin <npig...@gmail.com>
---
arch/powerpc/include/asm/kvm_book3s_64.h | 2 +-
arch/powerpc/kvm/book3s_hv.c | 88 +++++++++++++-----------
arch/powerpc/kvm/book3s_hv_p9_entry.c | 33 +++++----
3 files changed, 65 insertions(+), 58 deletions(-)
diff --git a/arch/powerpc/include/asm/kvm_book3s_64.h
b/arch/powerpc/include/asm/kvm_book3s_64.h
index df6bed4b2a46..52e2b7a352c7 100644
--- a/arch/powerpc/include/asm/kvm_book3s_64.h
+++ b/arch/powerpc/include/asm/kvm_book3s_64.h
@@ -154,7 +154,7 @@ static inline bool kvmhv_vcpu_is_radix(struct kvm_vcpu
*vcpu)
return radix;
}
-int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64 time_limit, unsigned long
lpcr);
+int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64 time_limit, unsigned long
lpcr, u64 *tb);
#define KVM_DEFAULT_HPT_ORDER 24 /* 16MB HPT by default */
#endif
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 027ae0b60e70..fa44bbca75e4 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -276,22 +276,22 @@ static void kvmppc_fast_vcpu_kick_hv(struct kvm_vcpu
*vcpu)
* they should never fail.)
*/
-static void kvmppc_core_start_stolen(struct kvmppc_vcore *vc)
+static void kvmppc_core_start_stolen(struct kvmppc_vcore *vc, u64 tb)
{
unsigned long flags;
spin_lock_irqsave(&vc->stoltb_lock, flags);
- vc->preempt_tb = mftb();
+ vc->preempt_tb = tb;
spin_unlock_irqrestore(&vc->stoltb_lock, flags);
}
-static void kvmppc_core_end_stolen(struct kvmppc_vcore *vc)
+static void kvmppc_core_end_stolen(struct kvmppc_vcore *vc, u64 tb)
{
unsigned long flags;
spin_lock_irqsave(&vc->stoltb_lock, flags);
if (vc->preempt_tb != TB_NIL) {
- vc->stolen_tb += mftb() - vc->preempt_tb;
+ vc->stolen_tb += tb - vc->preempt_tb;
vc->preempt_tb = TB_NIL;
}
spin_unlock_irqrestore(&vc->stoltb_lock, flags);
@@ -301,6 +301,7 @@ static void kvmppc_core_vcpu_load_hv(struct kvm_vcpu *vcpu,
int cpu)
{
struct kvmppc_vcore *vc = vcpu->arch.vcore;
unsigned long flags;
+ u64 now = mftb();
/*
* We can test vc->runner without taking the vcore lock,
@@ -309,12 +310,12 @@ static void kvmppc_core_vcpu_load_hv(struct kvm_vcpu
*vcpu, int cpu)
* ever sets it to NULL.
*/
if (vc->runner == vcpu && vc->vcore_state >= VCORE_SLEEPING)
- kvmppc_core_end_stolen(vc);
+ kvmppc_core_end_stolen(vc, now);
spin_lock_irqsave(&vcpu->arch.tbacct_lock, flags);
if (vcpu->arch.state == KVMPPC_VCPU_BUSY_IN_HOST &&
vcpu->arch.busy_preempt != TB_NIL) {
- vcpu->arch.busy_stolen += mftb() - vcpu->arch.busy_preempt;
+ vcpu->arch.busy_stolen += now - vcpu->arch.busy_preempt;
vcpu->arch.busy_preempt = TB_NIL;
}
spin_unlock_irqrestore(&vcpu->arch.tbacct_lock, flags);
@@ -324,13 +325,14 @@ static void kvmppc_core_vcpu_put_hv(struct kvm_vcpu *vcpu)
{
struct kvmppc_vcore *vc = vcpu->arch.vcore;
unsigned long flags;
+ u64 now = mftb();
if (vc->runner == vcpu && vc->vcore_state >= VCORE_SLEEPING)
- kvmppc_core_start_stolen(vc);
+ kvmppc_core_start_stolen(vc, now);
spin_lock_irqsave(&vcpu->arch.tbacct_lock, flags);
if (vcpu->arch.state == KVMPPC_VCPU_BUSY_IN_HOST)
- vcpu->arch.busy_preempt = mftb();
+ vcpu->arch.busy_preempt = now;
spin_unlock_irqrestore(&vcpu->arch.tbacct_lock, flags);
}
@@ -685,7 +687,7 @@ static u64 vcore_stolen_time(struct kvmppc_vcore *vc, u64
now)
}
static void kvmppc_create_dtl_entry(struct kvm_vcpu *vcpu,
- struct kvmppc_vcore *vc)
+ struct kvmppc_vcore *vc, u64 tb)
{
struct dtl_entry *dt;
struct lppaca *vpa;
@@ -696,7 +698,7 @@ static void kvmppc_create_dtl_entry(struct kvm_vcpu *vcpu,
dt = vcpu->arch.dtl_ptr;
vpa = vcpu->arch.vpa.pinned_addr;
- now = mftb();
+ now = tb;
core_stolen = vcore_stolen_time(vc, now);
stolen = core_stolen - vcpu->arch.stolen_logged;
vcpu->arch.stolen_logged = core_stolen;
@@ -2889,14 +2891,14 @@ static void kvmppc_set_timer(struct kvm_vcpu *vcpu)
extern int __kvmppc_vcore_entry(void);
static void kvmppc_remove_runnable(struct kvmppc_vcore *vc,
- struct kvm_vcpu *vcpu)
+ struct kvm_vcpu *vcpu, u64 tb)
{
u64 now;
if (vcpu->arch.state != KVMPPC_VCPU_RUNNABLE)
return;
spin_lock_irq(&vcpu->arch.tbacct_lock);
- now = mftb();
+ now = tb;
vcpu->arch.busy_stolen += vcore_stolen_time(vc, now) -
vcpu->arch.stolen_logged;
vcpu->arch.busy_preempt = now;
@@ -3147,14 +3149,14 @@ static void kvmppc_vcore_preempt(struct kvmppc_vcore
*vc)
}
/* Start accumulating stolen time */
- kvmppc_core_start_stolen(vc);
+ kvmppc_core_start_stolen(vc, mftb());
}
static void kvmppc_vcore_end_preempt(struct kvmppc_vcore *vc)
{
struct preempted_vcore_list *lp;
- kvmppc_core_end_stolen(vc);
+ kvmppc_core_end_stolen(vc, mftb());
if (!list_empty(&vc->preempt_list)) {
lp = &per_cpu(preempted_vcores, vc->pcpu);
spin_lock(&lp->lock);
@@ -3281,7 +3283,7 @@ static void prepare_threads(struct kvmppc_vcore *vc)
vcpu->arch.ret = RESUME_GUEST;
else
continue;
- kvmppc_remove_runnable(vc, vcpu);
+ kvmppc_remove_runnable(vc, vcpu, mftb());
wake_up(&vcpu->arch.cpu_run);
}
}
@@ -3300,7 +3302,7 @@ static void collect_piggybacks(struct core_info *cip, int
target_threads)
list_del_init(&pvc->preempt_list);
if (pvc->runner == NULL) {
pvc->vcore_state = VCORE_INACTIVE;
- kvmppc_core_end_stolen(pvc);
+ kvmppc_core_end_stolen(pvc, mftb());
}
spin_unlock(&pvc->lock);
continue;
@@ -3309,7 +3311,7 @@ static void collect_piggybacks(struct core_info *cip, int
target_threads)
spin_unlock(&pvc->lock);
continue;
}
- kvmppc_core_end_stolen(pvc);
+ kvmppc_core_end_stolen(pvc, mftb());
pvc->vcore_state = VCORE_PIGGYBACK;
if (cip->total_threads >= target_threads)
break;
@@ -3376,7 +3378,7 @@ static void post_guest_process(struct kvmppc_vcore *vc,
bool is_master)
else
++still_running;
} else {
- kvmppc_remove_runnable(vc, vcpu);
+ kvmppc_remove_runnable(vc, vcpu, mftb());
wake_up(&vcpu->arch.cpu_run);
}
}
@@ -3385,7 +3387,7 @@ static void post_guest_process(struct kvmppc_vcore *vc,
bool is_master)
kvmppc_vcore_preempt(vc);
} else if (vc->runner) {
vc->vcore_state = VCORE_PREEMPT;
- kvmppc_core_start_stolen(vc);
+ kvmppc_core_start_stolen(vc, mftb());
} else {
vc->vcore_state = VCORE_INACTIVE;
}
@@ -3516,7 +3518,7 @@ static noinline void kvmppc_run_core(struct kvmppc_vcore
*vc)
((vc->num_threads > threads_per_subcore) || !on_primary_thread())) {
for_each_runnable_thread(i, vcpu, vc) {
vcpu->arch.ret = -EBUSY;
- kvmppc_remove_runnable(vc, vcpu);
+ kvmppc_remove_runnable(vc, vcpu, mftb());
wake_up(&vcpu->arch.cpu_run);
}
goto out;
@@ -3648,7 +3650,7 @@ static noinline void kvmppc_run_core(struct kvmppc_vcore
*vc)
pvc->pcpu = pcpu + thr;
for_each_runnable_thread(i, vcpu, pvc) {
kvmppc_start_thread(vcpu, pvc);
- kvmppc_create_dtl_entry(vcpu, pvc);
+ kvmppc_create_dtl_entry(vcpu, pvc, mftb());
trace_kvm_guest_enter(vcpu);
if (!vcpu->arch.ptid)
thr0_done = true;
@@ -4102,20 +4104,17 @@ static void vcpu_vpa_increment_dispatch(struct kvm_vcpu
*vcpu)
* Guest entry for POWER9 and later CPUs.
*/
static int kvmhv_p9_guest_entry(struct kvm_vcpu *vcpu, u64 time_limit,
- unsigned long lpcr)
+ unsigned long lpcr, u64 *tb)
{
struct kvmppc_vcore *vc = vcpu->arch.vcore;
struct p9_host_os_sprs host_os_sprs;
s64 dec;
- u64 tb, next_timer;
+ u64 next_timer;
unsigned long msr;
int trap;
- WARN_ON_ONCE(vcpu->arch.ceded);
-
- tb = mftb();
next_timer = timer_get_next_tb();
- if (tb >= next_timer)
+ if (*tb >= next_timer)
return BOOK3S_INTERRUPT_HV_DECREMENTER;
if (next_timer < time_limit)
time_limit = next_timer;
@@ -4212,7 +4211,7 @@ static int kvmhv_p9_guest_entry(struct kvm_vcpu *vcpu,
u64 time_limit,
*
* XXX: Another day's problem.
*/
- mtspr(SPRN_DEC, kvmppc_dec_expires_host_tb(vcpu) - tb);
+ mtspr(SPRN_DEC, kvmppc_dec_expires_host_tb(vcpu) - *tb);
mtspr(SPRN_DAR, vcpu->arch.shregs.dar);
mtspr(SPRN_DSISR, vcpu->arch.shregs.dsisr);
@@ -4228,8 +4227,8 @@ static int kvmhv_p9_guest_entry(struct kvm_vcpu *vcpu,
u64 time_limit,
dec = mfspr(SPRN_DEC);
if (!(lpcr & LPCR_LD)) /* Sign extend if not using large
decrementer */
dec = (s32) dec;
- tb = mftb();
- vcpu->arch.dec_expires = dec + (tb + vc->tb_offset);
+ *tb = mftb();
+ vcpu->arch.dec_expires = dec + (*tb + vc->tb_offset);
/* H_CEDE has to be handled now, not later */
if (trap == BOOK3S_INTERRUPT_SYSCALL && !vcpu->arch.nested &&
@@ -4241,7 +4240,7 @@ static int kvmhv_p9_guest_entry(struct kvm_vcpu *vcpu,
u64 time_limit,
} else {
kvmppc_xive_push_vcpu(vcpu);
- trap = kvmhv_vcpu_entry_p9(vcpu, time_limit, lpcr);
+ trap = kvmhv_vcpu_entry_p9(vcpu, time_limit, lpcr, tb);
if (trap == BOOK3S_INTERRUPT_SYSCALL && !vcpu->arch.nested &&
!(vcpu->arch.shregs.msr & MSR_PR)) {
unsigned long req = kvmppc_get_gpr(vcpu, 3);
@@ -4272,6 +4271,8 @@ static int kvmhv_p9_guest_entry(struct kvm_vcpu *vcpu,
u64 time_limit,
store_spr_state(vcpu);
+ timer_rearm_host_dec(*tb);
+
restore_p9_host_os_sprs(vcpu, &host_os_sprs);
store_fp_state(&vcpu->arch.fp);
@@ -4291,8 +4292,6 @@ static int kvmhv_p9_guest_entry(struct kvm_vcpu *vcpu,
u64 time_limit,
vc->entry_exit_map = 0x101;
vc->in_guest = 0;
- timer_rearm_host_dec(tb);
-
kvmppc_subcore_exit_guest();
return trap;
@@ -4534,7 +4533,7 @@ static int kvmppc_run_vcpu(struct kvm_vcpu *vcpu)
if ((vc->vcore_state == VCORE_PIGGYBACK ||
vc->vcore_state == VCORE_RUNNING) &&
!VCORE_IS_EXITING(vc)) {
- kvmppc_create_dtl_entry(vcpu, vc);
+ kvmppc_create_dtl_entry(vcpu, vc, mftb());
kvmppc_start_thread(vcpu, vc);
trace_kvm_guest_enter(vcpu);
} else if (vc->vcore_state == VCORE_SLEEPING) {
@@ -4569,7 +4568,7 @@ static int kvmppc_run_vcpu(struct kvm_vcpu *vcpu)
for_each_runnable_thread(i, v, vc) {
kvmppc_core_prepare_to_enter(v);
if (signal_pending(v->arch.run_task)) {
- kvmppc_remove_runnable(vc, v);
+ kvmppc_remove_runnable(vc, v, mftb());
v->stat.signal_exits++;
v->run->exit_reason = KVM_EXIT_INTR;
v->arch.ret = -EINTR;
@@ -4610,7 +4609,7 @@ static int kvmppc_run_vcpu(struct kvm_vcpu *vcpu)
kvmppc_vcore_end_preempt(vc);
if (vcpu->arch.state == KVMPPC_VCPU_RUNNABLE) {
- kvmppc_remove_runnable(vc, vcpu);
+ kvmppc_remove_runnable(vc, vcpu, mftb());
vcpu->stat.signal_exits++;
run->exit_reason = KVM_EXIT_INTR;
vcpu->arch.ret = -EINTR;
@@ -4638,6 +4637,7 @@ int kvmhv_run_single_vcpu(struct kvm_vcpu *vcpu, u64
time_limit,
struct kvm *kvm = vcpu->kvm;
struct kvm_nested_guest *nested = vcpu->arch.nested;
unsigned long flags;
+ u64 tb;
trace_kvmppc_run_vcpu_enter(vcpu);
@@ -4648,7 +4648,6 @@ int kvmhv_run_single_vcpu(struct kvm_vcpu *vcpu, u64
time_limit,
vc = vcpu->arch.vcore;
vcpu->arch.ceded = 0;
vcpu->arch.run_task = current;
- vcpu->arch.stolen_logged = vcore_stolen_time(vc, mftb());
vcpu->arch.state = KVMPPC_VCPU_RUNNABLE;
vcpu->arch.busy_preempt = TB_NIL;
vcpu->arch.last_inst = KVM_INST_FETCH_FAILED;
@@ -4673,7 +4672,6 @@ int kvmhv_run_single_vcpu(struct kvm_vcpu *vcpu, u64
time_limit,
kvmppc_update_vpas(vcpu);
init_vcore_to_run(vc);
- vc->preempt_tb = TB_NIL;
preempt_disable();
pcpu = smp_processor_id();
@@ -4683,6 +4681,7 @@ int kvmhv_run_single_vcpu(struct kvm_vcpu *vcpu, u64
time_limit,
/* flags save not required, but irq_pmu has no disable/enable API */
powerpc_local_irq_pmu_save(flags);
+
if (signal_pending(current))
goto sigpend;
if (need_resched() || !kvm->arch.mmu_ready)
@@ -4705,12 +4704,17 @@ int kvmhv_run_single_vcpu(struct kvm_vcpu *vcpu, u64
time_limit,
goto out;
}
+ tb = mftb();
+
+ vcpu->arch.stolen_logged = vcore_stolen_time(vc, tb);
+ vc->preempt_tb = TB_NIL;
+
kvmppc_clear_host_core(pcpu);
local_paca->kvm_hstate.napping = 0;
local_paca->kvm_hstate.kvm_split_mode = NULL;
kvmppc_start_thread(vcpu, vc);
- kvmppc_create_dtl_entry(vcpu, vc);
+ kvmppc_create_dtl_entry(vcpu, vc, tb);
trace_kvm_guest_enter(vcpu);
vc->vcore_state = VCORE_RUNNING;
@@ -4725,7 +4729,7 @@ int kvmhv_run_single_vcpu(struct kvm_vcpu *vcpu, u64
time_limit,
/* Tell lockdep that we're about to enable interrupts */
trace_hardirqs_on();
- trap = kvmhv_p9_guest_entry(vcpu, time_limit, lpcr);
+ trap = kvmhv_p9_guest_entry(vcpu, time_limit, lpcr, &tb);
vcpu->arch.trap = trap;
trace_hardirqs_off();
@@ -4754,7 +4758,7 @@ int kvmhv_run_single_vcpu(struct kvm_vcpu *vcpu, u64
time_limit,
* by L2 and the L1 decrementer is provided in hdec_expires
*/
if (kvmppc_core_pending_dec(vcpu) &&
- ((get_tb() < kvmppc_dec_expires_host_tb(vcpu)) ||
+ ((tb < kvmppc_dec_expires_host_tb(vcpu)) ||
(trap == BOOK3S_INTERRUPT_SYSCALL &&
kvmppc_get_gpr(vcpu, 3) == H_ENTER_NESTED)))
kvmppc_core_dequeue_dec(vcpu);
@@ -4790,7 +4794,7 @@ int kvmhv_run_single_vcpu(struct kvm_vcpu *vcpu, u64
time_limit,
trace_kvmppc_run_core(vc, 1);
done:
- kvmppc_remove_runnable(vc, vcpu);
+ kvmppc_remove_runnable(vc, vcpu, tb);
trace_kvmppc_run_vcpu_exit(vcpu);
return vcpu->arch.ret;
diff --git a/arch/powerpc/kvm/book3s_hv_p9_entry.c
b/arch/powerpc/kvm/book3s_hv_p9_entry.c
index e7793bb806eb..2bd96d8256d1 100644
--- a/arch/powerpc/kvm/book3s_hv_p9_entry.c
+++ b/arch/powerpc/kvm/book3s_hv_p9_entry.c
@@ -183,13 +183,13 @@ static void save_clear_guest_mmu(struct kvm *kvm, struct
kvm_vcpu *vcpu)
}
}
-int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64 time_limit, unsigned long
lpcr)
+int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64 time_limit, unsigned long
lpcr, u64 *tb)
{
struct kvm *kvm = vcpu->kvm;
struct kvm_nested_guest *nested = vcpu->arch.nested;
struct kvmppc_vcore *vc = vcpu->arch.vcore;
s64 hdec, dec;
- u64 tb, purr, spurr;
+ u64 purr, spurr;
u64 *exsave;
bool ri_set;
int trap;
@@ -203,8 +203,7 @@ int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64
time_limit, unsigned long lpc
unsigned long host_dawr1;
unsigned long host_dawrx1;
- tb = mftb();
- hdec = time_limit - tb;
+ hdec = time_limit - *tb;
if (hdec < 0)
return BOOK3S_INTERRUPT_HV_DECREMENTER;
@@ -230,11 +229,13 @@ int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64
time_limit, unsigned long lpc
}
if (vc->tb_offset) {
- u64 new_tb = tb + vc->tb_offset;
+ u64 new_tb = *tb + vc->tb_offset;
mtspr(SPRN_TBU40, new_tb);
- tb = mftb();
- if ((tb & 0xffffff) < (new_tb & 0xffffff))
- mtspr(SPRN_TBU40, new_tb + 0x1000000);
+ if ((mftb() & 0xffffff) < (new_tb & 0xffffff)) {
+ new_tb += 0x1000000;
+ mtspr(SPRN_TBU40, new_tb);
+ }
+ *tb = new_tb;
vc->tb_offset_applied = vc->tb_offset;
}
@@ -317,7 +318,7 @@ int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64
time_limit, unsigned long lpc
*/
mtspr(SPRN_HDEC, hdec);
- mtspr(SPRN_DEC, vcpu->arch.dec_expires - tb);
+ mtspr(SPRN_DEC, vcpu->arch.dec_expires - *tb);
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
tm_return_to_guest:
@@ -466,15 +467,17 @@ int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64
time_limit, unsigned long lpc
dec = mfspr(SPRN_DEC);
if (!(lpcr & LPCR_LD)) /* Sign extend if not using large decrementer */
dec = (s32) dec;
- tb = mftb();
- vcpu->arch.dec_expires = dec + tb;
+ *tb = mftb();
+ vcpu->arch.dec_expires = dec + *tb;
if (vc->tb_offset_applied) {
- u64 new_tb = tb - vc->tb_offset_applied;
+ u64 new_tb = *tb - vc->tb_offset_applied;
mtspr(SPRN_TBU40, new_tb);
- tb = mftb();
- if ((tb & 0xffffff) < (new_tb & 0xffffff))
- mtspr(SPRN_TBU40, new_tb + 0x1000000);
+ if ((mftb() & 0xffffff) < (new_tb & 0xffffff)) {
+ new_tb += 0x1000000;
+ mtspr(SPRN_TBU40, new_tb);
+ }
+ *tb = new_tb;
vc->tb_offset_applied = 0;
}
--
2.23.0
