hlt emulation for in kernel apic/ioapic

hlt emulation for in kernel apic/ioapic

[Dong, Eddie]

[-- Attachment #1: Type: text/plain, Size: 5773 bytes --]

Rebased hlt emulation for in kernel APIC/PIC/IOAPIC base on Greg's
original V09.




Signed-off-by: Gregory Haskins [ghaskins-Et1tbQHTxzrQT0dZR+AlfA@public.gmane.org]
Signed-off-by: Yaozu (Eddie) Dong <eddie.dong-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>

diff --git a/drivers/kvm/i8259.c b/drivers/kvm/i8259.c
index f4ae5f7..4237e17 100644
--- a/drivers/kvm/i8259.c
+++ b/drivers/kvm/i8259.c
@@ -411,8 +411,10 @@ static void picdev_read(struct kvm_io_device *this,
 static void pic_irq_request(void *opaque, int level)
 {
 	struct kvm *kvm = opaque;
+	struct kvm_vcpu *vcpu = &kvm->vcpus[0];
 
 	pic_irqchip(kvm)->output = level;
+	kvm_vcpu_kick(vcpu);
 }
 
 struct kvm_pic *kvm_create_pic(struct kvm *kvm)
diff --git a/drivers/kvm/irq.c b/drivers/kvm/irq.c
index 5265f82..e09cd65 100644
--- a/drivers/kvm/irq.c
+++ b/drivers/kvm/irq.c
@@ -70,6 +70,10 @@ void kvm_vcpu_kick(struct kvm_vcpu *vcpu)
 {
 	int ipi_pcpu = vcpu->cpu;
 
+	if (waitqueue_active(&vcpu->wq)) {
+		wake_up_interruptible(&vcpu->wq);
+		++vcpu->stat.halt_wakeup;
+	}
 	if (vcpu->guest_mode)
 		smp_call_function_single(ipi_pcpu, vcpu_kick_intr, vcpu,
0, 0);
 }
diff --git a/drivers/kvm/kvm.h b/drivers/kvm/kvm.h
index 9dbdf04..d7e16ba 100644
--- a/drivers/kvm/kvm.h
+++ b/drivers/kvm/kvm.h
@@ -242,6 +242,7 @@ struct kvm_stat {
 	u32 signal_exits;
 	u32 irq_window_exits;
 	u32 halt_exits;
+	u32 halt_wakeup;
 	u32 request_irq_exits;
 	u32 irq_exits;
 	u32 light_exits;
@@ -392,6 +393,7 @@ struct kvm_vcpu {
 	gva_t mmio_fault_cr2;
 	struct kvm_pio_request pio;
 	void *pio_data;
+	wait_queue_head_t wq;
 
 	int sigset_active;
 	sigset_t sigset;
diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index 864c251..3218303 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -72,6 +72,7 @@ static struct kvm_stats_debugfs_item {
 	{ "signal_exits", STAT_OFFSET(signal_exits) },
 	{ "irq_window", STAT_OFFSET(irq_window_exits) },
 	{ "halt_exits", STAT_OFFSET(halt_exits) },
+	{ "halt_wakeup", STAT_OFFSET(halt_wakeup) },
 	{ "request_irq", STAT_OFFSET(request_irq_exits) },
 	{ "irq_exits", STAT_OFFSET(irq_exits) },
 	{ "light_exits", STAT_OFFSET(light_exits) },
@@ -314,6 +315,7 @@ static struct kvm *kvm_create_vm(void)
 		vcpu->cpu = -1;
 		vcpu->kvm = kvm;
 		vcpu->mmu.root_hpa = INVALID_PAGE;
+		init_waitqueue_head(&vcpu->wq);
 	}
 	return kvm;
 }
@@ -1337,15 +1339,41 @@ int emulate_instruction(struct kvm_vcpu *vcpu,
 }
 EXPORT_SYMBOL_GPL(emulate_instruction);
 
-int kvm_emulate_halt(struct kvm_vcpu *vcpu)
+/*
+ * The vCPU has executed a HLT instruction with in-kernel mode enabled.
+ */
+static void kvm_vcpu_kernel_halt(struct kvm_vcpu *vcpu)
 {
-	if (vcpu->irq_summary ||
-		(irqchip_in_kernel(vcpu->kvm) &&
kvm_cpu_has_interrupt(vcpu)))
-		return 1;
+	DECLARE_WAITQUEUE(wait, current);
+
+	add_wait_queue(&vcpu->wq, &wait);
 
-	vcpu->run->exit_reason = KVM_EXIT_HLT;
+	/*
+	 * We will block until either an interrupt or a signal wakes us
up
+	 */
+	while(!(irqchip_in_kernel(vcpu->kvm) &&
kvm_cpu_has_interrupt(vcpu))
+	      && !vcpu->irq_summary
+	      && !signal_pending(current)) {
+		set_current_state(TASK_INTERRUPTIBLE);
+		vcpu_put(vcpu);
+		schedule();
+		vcpu_load(vcpu);
+	}
+
+	remove_wait_queue(&vcpu->wq, &wait);
+	set_current_state(TASK_RUNNING);
+}
+
+int kvm_emulate_halt(struct kvm_vcpu *vcpu)
+{
 	++vcpu->stat.halt_exits;
-	return 0;
+	if (irqchip_in_kernel(vcpu->kvm)) {
+		kvm_vcpu_kernel_halt(vcpu);
+		return 1;
+	} else {
+		vcpu->run->exit_reason = KVM_EXIT_HLT;
+		return 0;
+	}
 }
 EXPORT_SYMBOL_GPL(kvm_emulate_halt);
 
@@ -2983,6 +3011,7 @@ static long kvm_dev_ioctl(struct file *filp,
 
 		switch (ext) {
 		case KVM_CAP_PIC:
+		case KVM_CAP_HLT:
 			r = 1;
 			break;
 		default:
diff --git a/drivers/kvm/lapic.c b/drivers/kvm/lapic.c
diff --git a/drivers/kvm/svm.c b/drivers/kvm/svm.c
index 03478e6..f3ec320 100644
--- a/drivers/kvm/svm.c
+++ b/drivers/kvm/svm.c
@@ -1472,8 +1472,12 @@ static void do_interrupt_requests(struct kvm_vcpu
*vcpu,
 static void post_kvm_run_save(struct kvm_vcpu *vcpu,
 			      struct kvm_run *kvm_run)
 {
-	kvm_run->ready_for_interrupt_injection =
(vcpu->interrupt_window_open &&
-						  vcpu->irq_summary ==
0);
+	if (irqchip_in_kernel(vcpu->kvm))
+		kvm_run->ready_for_interrupt_injection = 1;
+	else
+		kvm_run->ready_for_interrupt_injection =
+					 (vcpu->interrupt_window_open &&
+					  vcpu->irq_summary == 0);
 	kvm_run->if_flag = (vcpu->svm->vmcb->save.rflags &
X86_EFLAGS_IF) != 0;
 	kvm_run->cr8 = get_cr8(vcpu);
 	kvm_run->apic_base = kvm_get_apic_base(vcpu);
diff --git a/drivers/kvm/vmx.c b/drivers/kvm/vmx.c
index 4d999c2..b58b121 100644
--- a/drivers/kvm/vmx.c
+++ b/drivers/kvm/vmx.c
@@ -1899,8 +1899,12 @@ static void post_kvm_run_save(struct kvm_vcpu
*vcpu,
 	kvm_run->if_flag = (vmcs_readl(GUEST_RFLAGS) & X86_EFLAGS_IF) !=
0;
 	kvm_run->cr8 = get_cr8(vcpu);
 	kvm_run->apic_base = kvm_get_apic_base(vcpu);
-	kvm_run->ready_for_interrupt_injection =
(vcpu->interrupt_window_open &&
-						  vcpu->irq_summary ==
0);
+	if (irqchip_in_kernel(vcpu->kvm))
+		kvm_run->ready_for_interrupt_injection = 1;
+	else
+		kvm_run->ready_for_interrupt_injection =
+					(vcpu->interrupt_window_open &&
+					 vcpu->irq_summary == 0);
 }
 
 static int handle_interrupt_window(struct kvm_vcpu *vcpu,
diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index 61cc2b0..5307ba3 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -288,6 +288,7 @@ struct kvm_signal_mask {
  * Extension capability list.
  */
 #define KVM_CAP_PIC	  0
+#define KVM_CAP_HLT	  1
 
 /*
  * ioctls for VM fds

[-- Attachment #2: pic-hlt5.user.patch --]
[-- Type: application/octet-stream, Size: 485 bytes --]

diff --git a/qemu/qemu-kvm.c b/qemu/qemu-kvm.c
index 1c7c14e..a5f3492 100644
--- a/qemu/qemu-kvm.c
+++ b/qemu/qemu-kvm.c
@@ -622,8 +622,7 @@ static int kvm_halt(void *opaque, int vcpu)
     env = envs[0];
     if (!((env->interrupt_request & CPU_INTERRUPT_HARD) &&
 	  (env->eflags & IF_MASK))) {
-	    /* TODO: for halt emulation, temply walkaround now */
-	    /* env->hflags |= HF_HALTED_MASK; */
+	    env->hflags |= HF_HALTED_MASK;
 	    env->exception_index = EXCP_HLT;
     }
 

[-- Attachment #3: pic-hlt5.patch --]
[-- Type: application/octet-stream, Size: 5320 bytes --]

diff --git a/drivers/kvm/i8259.c b/drivers/kvm/i8259.c
index f4ae5f7..4237e17 100644
--- a/drivers/kvm/i8259.c
+++ b/drivers/kvm/i8259.c
@@ -411,8 +411,10 @@ static void picdev_read(struct kvm_io_device *this,
 static void pic_irq_request(void *opaque, int level)
 {
 	struct kvm *kvm = opaque;
+	struct kvm_vcpu *vcpu = &kvm->vcpus[0];
 
 	pic_irqchip(kvm)->output = level;
+	kvm_vcpu_kick(vcpu);
 }
 
 struct kvm_pic *kvm_create_pic(struct kvm *kvm)
diff --git a/drivers/kvm/irq.c b/drivers/kvm/irq.c
index 5265f82..e09cd65 100644
--- a/drivers/kvm/irq.c
+++ b/drivers/kvm/irq.c
@@ -70,6 +70,10 @@ void kvm_vcpu_kick(struct kvm_vcpu *vcpu)
 {
 	int ipi_pcpu = vcpu->cpu;
 
+	if (waitqueue_active(&vcpu->wq)) {
+		wake_up_interruptible(&vcpu->wq);
+		++vcpu->stat.halt_wakeup;
+	}
 	if (vcpu->guest_mode)
 		smp_call_function_single(ipi_pcpu, vcpu_kick_intr, vcpu, 0, 0);
 }
diff --git a/drivers/kvm/kvm.h b/drivers/kvm/kvm.h
index 9dbdf04..d7e16ba 100644
--- a/drivers/kvm/kvm.h
+++ b/drivers/kvm/kvm.h
@@ -242,6 +242,7 @@ struct kvm_stat {
 	u32 signal_exits;
 	u32 irq_window_exits;
 	u32 halt_exits;
+	u32 halt_wakeup;
 	u32 request_irq_exits;
 	u32 irq_exits;
 	u32 light_exits;
@@ -392,6 +393,7 @@ struct kvm_vcpu {
 	gva_t mmio_fault_cr2;
 	struct kvm_pio_request pio;
 	void *pio_data;
+	wait_queue_head_t wq;
 
 	int sigset_active;
 	sigset_t sigset;
diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index 864c251..3218303 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -72,6 +72,7 @@ static struct kvm_stats_debugfs_item {
 	{ "signal_exits", STAT_OFFSET(signal_exits) },
 	{ "irq_window", STAT_OFFSET(irq_window_exits) },
 	{ "halt_exits", STAT_OFFSET(halt_exits) },
+	{ "halt_wakeup", STAT_OFFSET(halt_wakeup) },
 	{ "request_irq", STAT_OFFSET(request_irq_exits) },
 	{ "irq_exits", STAT_OFFSET(irq_exits) },
 	{ "light_exits", STAT_OFFSET(light_exits) },
@@ -314,6 +315,7 @@ static struct kvm *kvm_create_vm(void)
 		vcpu->cpu = -1;
 		vcpu->kvm = kvm;
 		vcpu->mmu.root_hpa = INVALID_PAGE;
+		init_waitqueue_head(&vcpu->wq);
 	}
 	return kvm;
 }
@@ -1337,15 +1339,41 @@ int emulate_instruction(struct kvm_vcpu *vcpu,
 }
 EXPORT_SYMBOL_GPL(emulate_instruction);
 
-int kvm_emulate_halt(struct kvm_vcpu *vcpu)
+/*
+ * The vCPU has executed a HLT instruction with in-kernel mode enabled.
+ */
+static void kvm_vcpu_kernel_halt(struct kvm_vcpu *vcpu)
 {
-	if (vcpu->irq_summary ||
-		(irqchip_in_kernel(vcpu->kvm) && kvm_cpu_has_interrupt(vcpu)))
-		return 1;
+	DECLARE_WAITQUEUE(wait, current);
+
+	add_wait_queue(&vcpu->wq, &wait);
 
-	vcpu->run->exit_reason = KVM_EXIT_HLT;
+	/*
+	 * We will block until either an interrupt or a signal wakes us up
+	 */
+	while(!(irqchip_in_kernel(vcpu->kvm) && kvm_cpu_has_interrupt(vcpu))
+	      && !vcpu->irq_summary
+	      && !signal_pending(current)) {
+		set_current_state(TASK_INTERRUPTIBLE);
+		vcpu_put(vcpu);
+		schedule();
+		vcpu_load(vcpu);
+	}
+
+	remove_wait_queue(&vcpu->wq, &wait);
+	set_current_state(TASK_RUNNING);
+}
+
+int kvm_emulate_halt(struct kvm_vcpu *vcpu)
+{
 	++vcpu->stat.halt_exits;
-	return 0;
+	if (irqchip_in_kernel(vcpu->kvm)) {
+		kvm_vcpu_kernel_halt(vcpu);
+		return 1;
+	} else {
+		vcpu->run->exit_reason = KVM_EXIT_HLT;
+		return 0;
+	}
 }
 EXPORT_SYMBOL_GPL(kvm_emulate_halt);
 
@@ -2983,6 +3011,7 @@ static long kvm_dev_ioctl(struct file *filp,
 
 		switch (ext) {
 		case KVM_CAP_PIC:
+		case KVM_CAP_HLT:
 			r = 1;
 			break;
 		default:
diff --git a/drivers/kvm/lapic.c b/drivers/kvm/lapic.c
diff --git a/drivers/kvm/svm.c b/drivers/kvm/svm.c
index 03478e6..f3ec320 100644
--- a/drivers/kvm/svm.c
+++ b/drivers/kvm/svm.c
@@ -1472,8 +1472,12 @@ static void do_interrupt_requests(struct kvm_vcpu *vcpu,
 static void post_kvm_run_save(struct kvm_vcpu *vcpu,
 			      struct kvm_run *kvm_run)
 {
-	kvm_run->ready_for_interrupt_injection = (vcpu->interrupt_window_open &&
-						  vcpu->irq_summary == 0);
+	if (irqchip_in_kernel(vcpu->kvm))
+		kvm_run->ready_for_interrupt_injection = 1;
+	else
+		kvm_run->ready_for_interrupt_injection =
+					 (vcpu->interrupt_window_open &&
+					  vcpu->irq_summary == 0);
 	kvm_run->if_flag = (vcpu->svm->vmcb->save.rflags & X86_EFLAGS_IF) != 0;
 	kvm_run->cr8 = get_cr8(vcpu);
 	kvm_run->apic_base = kvm_get_apic_base(vcpu);
diff --git a/drivers/kvm/vmx.c b/drivers/kvm/vmx.c
index 4d999c2..b58b121 100644
--- a/drivers/kvm/vmx.c
+++ b/drivers/kvm/vmx.c
@@ -1899,8 +1899,12 @@ static void post_kvm_run_save(struct kvm_vcpu *vcpu,
 	kvm_run->if_flag = (vmcs_readl(GUEST_RFLAGS) & X86_EFLAGS_IF) != 0;
 	kvm_run->cr8 = get_cr8(vcpu);
 	kvm_run->apic_base = kvm_get_apic_base(vcpu);
-	kvm_run->ready_for_interrupt_injection = (vcpu->interrupt_window_open &&
-						  vcpu->irq_summary == 0);
+	if (irqchip_in_kernel(vcpu->kvm))
+		kvm_run->ready_for_interrupt_injection = 1;
+	else
+		kvm_run->ready_for_interrupt_injection =
+					(vcpu->interrupt_window_open &&
+					 vcpu->irq_summary == 0);
 }
 
 static int handle_interrupt_window(struct kvm_vcpu *vcpu,
diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index 61cc2b0..5307ba3 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -288,6 +288,7 @@ struct kvm_signal_mask {
  * Extension capability list.
  */
 #define KVM_CAP_PIC	  0
+#define KVM_CAP_HLT	  1
 
 /*
  * ioctls for VM fds

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Re: hlt emulation for in kernel apic/ioapic

[Avi Kivity]

Dong, Eddie wrote:
> Rebased hlt emulation for in kernel APIC/PIC/IOAPIC base on Greg's
> original V09.
>
>
>   

Applied the kernel side.  Please resend the missing user side patchset.

-- 
Do not meddle in the internals of kernels, for they are subtle and quick to panic.


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