2014-11-14 15:19:04

by Chen Gang

[permalink] [raw]
Subject: [PATCH v2] 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(-)

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


2014-11-14 15:55:45

by Marc Zyngier

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

On 14/11/14 15:18, Chen Gang wrote:
> 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(-)
>
> 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...

2014-11-14 16:30:25

by Chen Gang

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


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

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

2014-11-30 03:18:48

by Chen Gang

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

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:
>>
>> 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