Merge branch 'topic/ppc-kvm' into next

Merge some KVM commits we are keeping in our topic branch.

arch/powerpc/kvm/book3s_hv.c

@@ -249,6 +249,7 @@ static void kvmppc_fast_vcpu_kick_hv(struct kvm_vcpu *vcpu)
 
 /*
  * We use the vcpu_load/put functions to measure stolen time.
+ *
  * Stolen time is counted as time when either the vcpu is able to
  * run as part of a virtual core, but the task running the vcore
  * is preempted or sleeping, or when the vcpu needs something done
@@ -278,6 +279,12 @@ static void kvmppc_fast_vcpu_kick_hv(struct kvm_vcpu *vcpu)
  * lock.  The stolen times are measured in units of timebase ticks.
  * (Note that the != TB_NIL checks below are purely defensive;
  * they should never fail.)
+ *
+ * The POWER9 path is simpler, one vcpu per virtual core so the
+ * former case does not exist. If a vcpu is preempted when it is
+ * BUSY_IN_HOST and not ceded or otherwise blocked, then accumulate
+ * the stolen cycles in busy_stolen. RUNNING is not a preemptible
+ * state in the P9 path.
  */
 
 static void kvmppc_core_start_stolen(struct kvmppc_vcore *vc, u64 tb)
@@ -311,8 +318,14 @@ static void kvmppc_core_vcpu_load_hv(struct kvm_vcpu *vcpu, int cpu)
 	unsigned long flags;
 	u64 now;
 
-	if (cpu_has_feature(CPU_FTR_ARCH_300))
+	if (cpu_has_feature(CPU_FTR_ARCH_300)) {
+		if (vcpu->arch.busy_preempt != TB_NIL) {
+			WARN_ON_ONCE(vcpu->arch.state != KVMPPC_VCPU_BUSY_IN_HOST);
+			vc->stolen_tb += mftb() - vcpu->arch.busy_preempt;
+			vcpu->arch.busy_preempt = TB_NIL;
+		}
 		return;
+	}
 
 	now = mftb();
 
@@ -340,8 +353,21 @@ static void kvmppc_core_vcpu_put_hv(struct kvm_vcpu *vcpu)
 	unsigned long flags;
 	u64 now;
 
-	if (cpu_has_feature(CPU_FTR_ARCH_300))
+	if (cpu_has_feature(CPU_FTR_ARCH_300)) {
+		/*
+		 * In the P9 path, RUNNABLE is not preemptible
+		 * (nor takes host interrupts)
+		 */
+		WARN_ON_ONCE(vcpu->arch.state == KVMPPC_VCPU_RUNNABLE);
+		/*
+		 * Account stolen time when preempted while the vcpu task is
+		 * running in the kernel (but not in qemu, which is INACTIVE).
+		 */
+		if (task_is_running(current) &&
+				vcpu->arch.state == KVMPPC_VCPU_BUSY_IN_HOST)
+			vcpu->arch.busy_preempt = mftb();
 		return;
+	}
 
 	now = mftb();
 
@@ -740,6 +766,18 @@ static void __kvmppc_create_dtl_entry(struct kvm_vcpu *vcpu,
 	vcpu->arch.dtl.dirty = true;
 }
 
+static void kvmppc_create_dtl_entry_p9(struct kvm_vcpu *vcpu,
+				       struct kvmppc_vcore *vc,
+				       u64 now)
+{
+	unsigned long stolen;
+
+	stolen = vc->stolen_tb - vcpu->arch.stolen_logged;
+	vcpu->arch.stolen_logged = vc->stolen_tb;
+
+	__kvmppc_create_dtl_entry(vcpu, vc->pcpu, now, stolen);
+}
+
 static void kvmppc_create_dtl_entry(struct kvm_vcpu *vcpu,
 				    struct kvmppc_vcore *vc)
 {
@@ -2517,10 +2555,24 @@ static int kvmppc_set_one_reg_hv(struct kvm_vcpu *vcpu, u64 id,
 		r = set_vpa(vcpu, &vcpu->arch.dtl, addr, len);
 		break;
 	case KVM_REG_PPC_TB_OFFSET:
+	{
 		/* round up to multiple of 2^24 */
-		vcpu->arch.vcore->tb_offset =
-			ALIGN(set_reg_val(id, *val), 1UL << 24);
+		u64 tb_offset = ALIGN(set_reg_val(id, *val), 1UL << 24);
+
+		/*
+		 * Now that we know the timebase offset, update the
+		 * decrementer expiry with a guest timebase value. If
+		 * the userspace does not set DEC_EXPIRY, this ensures
+		 * a migrated vcpu at least starts with an expired
+		 * decrementer, which is better than a large one that
+		 * causes a hang.
+		 */
+		if (!vcpu->arch.dec_expires && tb_offset)
+			vcpu->arch.dec_expires = get_tb() + tb_offset;
+
+		vcpu->arch.vcore->tb_offset = tb_offset;
 		break;
+	}
 	case KVM_REG_PPC_LPCR:
 		kvmppc_set_lpcr(vcpu, set_reg_val(id, *val), true);
 		break;
@@ -3840,23 +3892,17 @@ static noinline void kvmppc_run_core(struct kvmppc_vcore *vc)
 	for (sub = 0; sub < core_info.n_subcores; ++sub)
 		spin_unlock(&core_info.vc[sub]->lock);
 
-	guest_enter_irqoff();
+	guest_timing_enter_irqoff();
 
 	srcu_idx = srcu_read_lock(&vc->kvm->srcu);
 
+	guest_state_enter_irqoff();
 	this_cpu_disable_ftrace();
 
-	/*
-	 * Interrupts will be enabled once we get into the guest,
-	 * so tell lockdep that we're about to enable interrupts.
-	 */
-	trace_hardirqs_on();
-
 	trap = __kvmppc_vcore_entry();
 
-	trace_hardirqs_off();
-
 	this_cpu_enable_ftrace();
+	guest_state_exit_irqoff();
 
 	srcu_read_unlock(&vc->kvm->srcu, srcu_idx);
 
@@ -3891,11 +3937,10 @@ static noinline void kvmppc_run_core(struct kvmppc_vcore *vc)
 
 	kvmppc_set_host_core(pcpu);
 
-	context_tracking_guest_exit();
 	if (!vtime_accounting_enabled_this_cpu()) {
 		local_irq_enable();
 		/*
-		 * Service IRQs here before vtime_account_guest_exit() so any
+		 * Service IRQs here before guest_timing_exit_irqoff() so any
 		 * ticks that occurred while running the guest are accounted to
 		 * the guest. If vtime accounting is enabled, accounting uses
 		 * TB rather than ticks, so it can be done without enabling
@@ -3904,7 +3949,7 @@ static noinline void kvmppc_run_core(struct kvmppc_vcore *vc)
 		 */
 		local_irq_disable();
 	}
-	vtime_account_guest_exit();
+	guest_timing_exit_irqoff();
 
 	local_irq_enable();
 
@@ -4520,7 +4565,6 @@ 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.state = KVMPPC_VCPU_RUNNABLE;
 	vcpu->arch.last_inst = KVM_INST_FETCH_FAILED;
 
 	/* See if the MMU is ready to go */
@@ -4547,6 +4591,8 @@ 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);
 
+	vcpu->arch.state = KVMPPC_VCPU_RUNNABLE;
+
 	if (signal_pending(current))
 		goto sigpend;
 	if (need_resched() || !kvm->arch.mmu_ready)
@@ -4591,47 +4637,44 @@ int kvmhv_run_single_vcpu(struct kvm_vcpu *vcpu, u64 time_limit,
 
 	tb = mftb();
 
-	__kvmppc_create_dtl_entry(vcpu, pcpu, tb + vc->tb_offset, 0);
+	kvmppc_create_dtl_entry_p9(vcpu, vc, tb + vc->tb_offset);
 
 	trace_kvm_guest_enter(vcpu);
 
-	guest_enter_irqoff();
+	guest_timing_enter_irqoff();
 
 	srcu_idx = srcu_read_lock(&kvm->srcu);
 
+	guest_state_enter_irqoff();
 	this_cpu_disable_ftrace();
 
-	/* Tell lockdep that we're about to enable interrupts */
-	trace_hardirqs_on();
-
 	trap = kvmhv_p9_guest_entry(vcpu, time_limit, lpcr, &tb);
 	vcpu->arch.trap = trap;
 
-	trace_hardirqs_off();
-
 	this_cpu_enable_ftrace();
+	guest_state_exit_irqoff();
 
 	srcu_read_unlock(&kvm->srcu, srcu_idx);
 
 	set_irq_happened(trap);
 
-	context_tracking_guest_exit();
+	vcpu->cpu = -1;
+	vcpu->arch.thread_cpu = -1;
+	vcpu->arch.state = KVMPPC_VCPU_BUSY_IN_HOST;
+
 	if (!vtime_accounting_enabled_this_cpu()) {
-		local_irq_enable();
+		powerpc_local_irq_pmu_restore(flags);
 		/*
-		 * Service IRQs here before vtime_account_guest_exit() so any
+		 * Service IRQs here before guest_timing_exit_irqoff() so any
 		 * ticks that occurred while running the guest are accounted to
 		 * the guest. If vtime accounting is enabled, accounting uses
 		 * TB rather than ticks, so it can be done without enabling
 		 * interrupts here, which has the problem that it accounts
 		 * interrupt processing overhead to the host.
 		 */
-		local_irq_disable();
+		powerpc_local_irq_pmu_save(flags);
 	}
-	vtime_account_guest_exit();
-
-	vcpu->cpu = -1;
-	vcpu->arch.thread_cpu = -1;
+	guest_timing_exit_irqoff();
 
 	powerpc_local_irq_pmu_restore(flags);
 
@@ -4694,6 +4737,7 @@ int kvmhv_run_single_vcpu(struct kvm_vcpu *vcpu, u64 time_limit,
  out:
 	vcpu->cpu = -1;
 	vcpu->arch.thread_cpu = -1;
+	vcpu->arch.state = KVMPPC_VCPU_BUSY_IN_HOST;
 	powerpc_local_irq_pmu_restore(flags);
 	preempt_enable();
 	goto done;

arch/powerpc/kvm/powerpc.c

@@ -786,7 +786,6 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
 
 	hrtimer_init(&vcpu->arch.dec_timer, CLOCK_REALTIME, HRTIMER_MODE_ABS);
 	vcpu->arch.dec_timer.function = kvmppc_decrementer_wakeup;
-	vcpu->arch.dec_expires = get_tb();
 
 #ifdef CONFIG_KVM_EXIT_TIMING
 	mutex_init(&vcpu->arch.exit_timing_lock);