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

Subsystems: arm port, arm64 port (aarch64 architecture), kernel virtual machine (kvm), kernel virtual machine for arm64 (kvm/arm64), the rest

STALE4267d

4 messages, 2 authors, 2014-11-30 · open the first message on its own page

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

From: Chen Gang <hidden>
Date: 2014-11-14 15:19:04

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 <redacted>
---
 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(-)

diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
index 53036e2..f68e302 100644
--- a/arch/arm/include/asm/kvm_host.h
+++ b/arch/arm/include/asm/kvm_host.h

@@ -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);

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 2012c4b..597500c 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h

@@ -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) {}

diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c
index 3aaca49..bab81f7 100644
--- a/virt/kvm/arm/vgic.c
+++ b/virt/kvm/arm/vgic.c

@@ -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;

-- 
1.9.3

Re: [PATCH v2] virt: kvm: arm: vgic: Process the failure case when kvm_register_device_ops() fails

From: Marc Zyngier <hidden>
Date: 2014-11-14 15:55:45

On 14/11/14 15:18, Chen Gang wrote:

quoted hunk

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 <redacted>
---
 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(-)

diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
index 53036e2..f68e302 100644
--- a/arch/arm/include/asm/kvm_host.h
+++ b/arch/arm/include/asm/kvm_host.h

@@ -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);

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 2012c4b..597500c 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h

@@ -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) {}

diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c
index 3aaca49..bab81f7 100644
--- a/virt/kvm/arm/vgic.c
+++ b/virt/kvm/arm/vgic.c

@@ -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;

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

diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c
index 3aaca49..b7dffa80 100644
--- a/virt/kvm/arm/vgic.c
+++ b/virt/kvm/arm/vgic.c

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

Re: [PATCH v2] virt: kvm: arm: vgic: Process the failure case when kvm_register_device_ops() fails

From: Chen Gang <hidden>
Date: 2014-11-14 16:30:25

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

On 11/14/2014 11:55 PM, Marc Zyngier wrote:

quoted hunk

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

diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c
index 3aaca49..b7dffa80 100644
--- a/virt/kvm/arm/vgic.c
+++ b/virt/kvm/arm/vgic.c

@@ -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.

 	/* 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.


-- 
Chen Gang

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

Re: [PATCH v2] virt: kvm: arm: vgic: Process the failure case when kvm_register_device_ops() fails

From: Chen Gang <hidden>
Date: 2014-11-30 03:18:48

Hello maintainers:

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

Thanks.

On 11/15/14 00:30, Chen Gang wrote:

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

On 11/14/2014 11:55 PM, Marc Zyngier wrote:

quoted

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

diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c
index 3aaca49..b7dffa80 100644
--- a/virt/kvm/arm/vgic.c
+++ b/virt/kvm/arm/vgic.c

@@ -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

 	/* 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.

-- 
Chen Gang

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

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