virt: kvm: arm: vgic: Process the failure case when kvm_register_device_ops() fails

PATCH Superseded Chen Gang 2 participants 4 messages Nov 14, 2014 – Nov 30, 2014

Subsystems (4)

Arm (32-bit) KVM arm64 KVM arm64

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Chen Gang

author

2014-11-14 15:18 UTC #0 lore raw

PATCH v2 1/1 virt: kvm: arm: vgic: Process the failure case when kvm_register_device_ops() fails

When kvm_register_device_ops() fails, need disable_percpu_irq(), need vgic_arch_unsetup(), need __unregister_cpu_notifier(), and also need free_percpu_irq().

At present, there is no vgic_arch_unsetup(), so add it for resetting '__vgic_sr_vectors'.

Signed-off-by Chen Gang <[email protected]>

---
 arch/arm/include/asm/kvm_host.h   |  1 +
 arch/arm64/include/asm/kvm_host.h |  8 ++++++++
 virt/kvm/arm/vgic.c               | 19 +++++++++++++++++--
 3 files changed, 26 insertions(+), 2 deletions(-)

arch/arm/include/asm/kvm_host.h +1 -0

index 53036e2..f68e302 100644
@@ -232,6 +232,7 @@ static inline void vgic_arch_setup(const struct vgic_params *vgic)
 {
 	BUG_ON(vgic->type != VGIC_V2);
 }
+static inline void vgic_arch_unsetup(void) {}
 
 int kvm_perf_init(void);
 int kvm_perf_teardown(void);

arch/arm64/include/asm/kvm_host.h +8 -0

index 2012c4b..597500c 100644
@@ -248,6 +248,14 @@ static inline void vgic_arch_setup(const struct vgic_params *vgic)
 	}
 }
 
+static inline void vgic_arch_unsetup(void)
+{
+	extern struct vgic_sr_vectors __vgic_sr_vectors;
+
+	__vgic_sr_vectors.save_vgic	= 0;
+	__vgic_sr_vectors.restore_vgic	= 0;
+}
+
 static inline void kvm_arch_hardware_disable(void) {}
 static inline void kvm_arch_hardware_unsetup(void) {}
 static inline void kvm_arch_sync_events(struct kvm *kvm) {}

virt/kvm/arm/vgic.c +17 -2

index 3aaca49..bab81f7 100644
@@ -2405,6 +2405,11 @@ static void vgic_init_maintenance_interrupt(void *info)
 	enable_percpu_irq(vgic->maint_irq, 0);
 }
 
+static void vgic_uninit_maintenance_interrupt(void *info)
+{
+	disable_percpu_irq(vgic->maint_irq);
+}
+
 static int vgic_cpu_notify(struct notifier_block *self,
 			   unsigned long action, void *cpu)
 {

@@ -2470,9 +2475,19 @@ int kvm_vgic_hyp_init(void)
 
 	on_each_cpu(vgic_init_maintenance_interrupt, NULL, 1);
 
-	return kvm_register_device_ops(&kvm_arm_vgic_v2_ops,
-				       KVM_DEV_TYPE_ARM_VGIC_V2);
+	ret = kvm_register_device_ops(&kvm_arm_vgic_v2_ops,
+				      KVM_DEV_TYPE_ARM_VGIC_V2);
+	if (ret) {
+		kvm_err("Cannot register device ops\n");
+		goto out_disable_irq;
+	}
+
+	return 0;
 
+out_disable_irq:
+	on_each_cpu(vgic_uninit_maintenance_interrupt, NULL, 1);
+	vgic_arch_unsetup();
+	__unregister_cpu_notifier(&vgic_cpu_nb);
 out_free_irq:
 	free_percpu_irq(vgic->maint_irq, kvm_get_running_vcpus());
 	return ret;

Signature · 1 line

1.9.3

Marc Zyngier

2014-11-14 15:55 UTC #1 lore raw

Quoted 75 lines · Chen Gang

When kvm_register_device_ops() fails, need disable_percpu_irq(), need vgic_arch_unsetup(), need __unregister_cpu_notifier(), and also need free_percpu_irq().

At present, there is no vgic_arch_unsetup(), so add it for resetting '__vgic_sr_vectors'.

Signed-off-by Chen Gang <[email protected]>

---
 arch/arm/include/asm/kvm_host.h   |  1 +
 arch/arm64/include/asm/kvm_host.h |  8 ++++++++
 virt/kvm/arm/vgic.c               | 19 +++++++++++++++++--
 3 files changed, 26 insertions(+), 2 deletions(-)

arch/arm/include/asm/kvm_host.h +1 -0

index 53036e2..f68e302 100644
@@ -232,6 +232,7 @@ static inline void vgic_arch_setup(const struct vgic_params *vgic)
 {
 	BUG_ON(vgic->type != VGIC_V2);
 }
+static inline void vgic_arch_unsetup(void) {}
 
 int kvm_perf_init(void);
 int kvm_perf_teardown(void);

arch/arm64/include/asm/kvm_host.h +8 -0

index 2012c4b..597500c 100644
@@ -248,6 +248,14 @@ static inline void vgic_arch_setup(const struct vgic_params *vgic)
 	}
 }
 
+static inline void vgic_arch_unsetup(void)
+{
+	extern struct vgic_sr_vectors __vgic_sr_vectors;
+
+	__vgic_sr_vectors.save_vgic	= 0;
+	__vgic_sr_vectors.restore_vgic	= 0;
+}
+
 static inline void kvm_arch_hardware_disable(void) {}
 static inline void kvm_arch_hardware_unsetup(void) {}
 static inline void kvm_arch_sync_events(struct kvm *kvm) {}

virt/kvm/arm/vgic.c +11 -2

index 3aaca49..bab81f7 100644
@@ -2405,6 +2405,11 @@ static void vgic_init_maintenance_interrupt(void *info)
 	enable_percpu_irq(vgic->maint_irq, 0);
 }
 
+static void vgic_uninit_maintenance_interrupt(void *info)
+{
+	disable_percpu_irq(vgic->maint_irq);
+}
+
 static int vgic_cpu_notify(struct notifier_block *self,
 			   unsigned long action, void *cpu)
 {

@@ -2470,9 +2475,19 @@ int kvm_vgic_hyp_init(void)
 
 	on_each_cpu(vgic_init_maintenance_interrupt, NULL, 1);
 
-	return kvm_register_device_ops(&kvm_arm_vgic_v2_ops,
-				       KVM_DEV_TYPE_ARM_VGIC_V2);
+	ret = kvm_register_device_ops(&kvm_arm_vgic_v2_ops,
+				      KVM_DEV_TYPE_ARM_VGIC_V2);
+	if (ret) {
+		kvm_err("Cannot register device ops\n");
+		goto out_disable_irq;
+	}

virt/kvm/arm/vgic.c int kvm_vgic_hyp_init(void) · line 2493

Quoted 10 lines

virt/kvm/arm/vgic.c +6 -0

+
+	return 0;
 
+out_disable_irq:
+	on_each_cpu(vgic_uninit_maintenance_interrupt, NULL, 1);
+	vgic_arch_unsetup();
+	__unregister_cpu_notifier(&vgic_cpu_nb);
 out_free_irq:
 	free_percpu_irq(vgic->maint_irq, kvm_get_running_vcpus());
 	return ret;

No. This is completely overdesigned, and fixes something that really cannot happen. What is wrong with:

virt/kvm/arm/vgic.c +6 -2

index 3aaca49..b7dffa80 100644
@@ -2465,13 +2465,17 @@ int kvm_vgic_hyp_init(void)
 		goto out_free_irq;
 	}
 
+	ret = kvm_register_device_ops(&kvm_arm_vgic_v2_ops,
+				       KVM_DEV_TYPE_ARM_VGIC_V2);
+	if (ret)
+		goto out_free_irq;
+
 	/* Callback into for arch code for setup */
 	vgic_arch_setup(vgic);
 
 	on_each_cpu(vgic_init_maintenance_interrupt, NULL, 1);
 
-	return kvm_register_device_ops(&kvm_arm_vgic_v2_ops,
-				       KVM_DEV_TYPE_ARM_VGIC_V2);
+	return 0;
 
 out_free_irq:
 	free_percpu_irq(vgic->maint_irq, kvm_get_running_vcpus());

This achieves the exact same effect.

Thanks,

M.

Signature · 1 line

Jazz is not dead. It just smells funny...

Chen Gang

author

2014-11-14 16:30 UTC #2 lore raw

According to your taste, we need improve 2 contents below:

Quoted 9 lines · Marc Zyngier

No. This is completely overdesigned, and fixes something that really cannot happen. What is wrong with:
virt/kvm/arm/vgic.c +0 -0
index 3aaca49..b7dffa80 100644

virt/kvm/arm/vgic.c int kvm_vgic_hyp_init(void) · line 2472

Quoted 8 lines

virt/kvm/arm/vgic.c +5 -0

@@ -2465,13 +2465,17 @@ int kvm_vgic_hyp_init(void)
 		goto out_free_irq;
 	}
 
+	ret = kvm_register_device_ops(&kvm_arm_vgic_v2_ops,
+				       KVM_DEV_TYPE_ARM_VGIC_V2);
+	if (ret)
+		goto out_free_irq;
+

Need call __unregister_cpu_notifier(), since __register_cpu_notifier() is already successfully called.

Need print some information for failure via kvm_err().

Thanks.

Quoted 18 lines

virt/kvm/arm/vgic.c +1 -2

 	/* Callback into for arch code for setup */
 	vgic_arch_setup(vgic);
 
 	on_each_cpu(vgic_init_maintenance_interrupt, NULL, 1);
 
-	return kvm_register_device_ops(&kvm_arm_vgic_v2_ops,
-				       KVM_DEV_TYPE_ARM_VGIC_V2);
+	return 0;
 
 out_free_irq:
 	free_percpu_irq(vgic->maint_irq, kvm_get_running_vcpus());

This achieves the exact same effect.

Thanks,

M.

Signature · 3 lines

Chen Gang

Open share and attitude like air water and life which God blessed

Chen Gang

author

2014-11-30 03:18 UTC #3 lore raw

Hello maintainers:

Is this discussion OK? If necessary, I shall send patch v3 according to your taste.

Thanks.

Quoted 48 lines · Chen Gang

According to your taste, we need improve 2 contents below:
Quoted 9 lines · Marc Zyngier
No. This is completely overdesigned, and fixes something that really cannot happen. What is wrong with:
virt/kvm/arm/vgic.c +0 -0
index 3aaca49..b7dffa80 100644
virt/kvm/arm/vgic.c int kvm_vgic_hyp_init(void) · line 2472
Quoted 8 lines
virt/kvm/arm/vgic.c +5 -0
@@ -2465,13 +2465,17 @@ int kvm_vgic_hyp_init(void)
 		goto out_free_irq;
 	}
 
+	ret = kvm_register_device_ops(&kvm_arm_vgic_v2_ops,
+				       KVM_DEV_TYPE_ARM_VGIC_V2);
+	if (ret)
+		goto out_free_irq;
+
Need call __unregister_cpu_notifier(), since __register_cpu_notifier() is already successfully called.
Need print some information for failure via kvm_err().
Thanks.
Quoted 18 lines
virt/kvm/arm/vgic.c +1 -2
 	/* Callback into for arch code for setup */
 	vgic_arch_setup(vgic);
 
 	on_each_cpu(vgic_init_maintenance_interrupt, NULL, 1);
 
-	return kvm_register_device_ops(&kvm_arm_vgic_v2_ops,
-				       KVM_DEV_TYPE_ARM_VGIC_V2);
+	return 0;
 
 out_free_irq:
 	free_percpu_irq(vgic->maint_irq, kvm_get_running_vcpus());
This achieves the exact same effect.
Thanks,
	M.

Signature · 3 lines

Chen Gang

Open, share, and attitude like air, water, and life which God blessed