At 07/21/2012 03:19 PM, Jan Kiszka Wrote:
> On 2012-07-21 09:12, Wen Congyang wrote:
>> We can know the guest is panicked when the guest runs on xen.
>> But we do not have such feature on kvm.
>>
>> Another purpose of this feature is: management app(for example:
>> libvirt) can do auto dump when the guest is panicked. If management
>> app does not do auto dump, the guest's user can do dump by hand if
>> he sees the guest is panicked.
>>
>> We have three solutions to implement this feature:
>> 1. use vmcall
>> 2. use I/O port
>> 3. use virtio-serial.
>>
>> We have decided to avoid touching hypervisor. The reason why I choose
>> choose the I/O port is:
>> 1. it is easier to implememt
>> 2. it does not depend any virtual device
>> 3. it can work when startint the kernel
>>
>> Signed-off-by: Wen Congyang <wency@xxxxxxxxxxxxxx>
>> ---
>> arch/ia64/include/asm/kvm_para.h | 5 +++++
>> arch/powerpc/include/asm/kvm_para.h | 5 +++++
>> arch/s390/include/asm/kvm_para.h | 5 +++++
>> arch/x86/include/asm/kvm_para.h | 7 +++++++
>> arch/x86/kernel/kvm.c | 14 ++++++++++++++
>> include/linux/kvm_para.h | 13 +++++++++++++
>> 6 files changed, 49 insertions(+), 0 deletions(-)
>>
>> diff --git a/arch/ia64/include/asm/kvm_para.h b/arch/ia64/include/asm/kvm_para.h
>> index 2019cb9..187c0e2 100644
>> --- a/arch/ia64/include/asm/kvm_para.h
>> +++ b/arch/ia64/include/asm/kvm_para.h
>> @@ -31,6 +31,11 @@ static inline bool kvm_check_and_clear_guest_paused(void)
>> return false;
>> }
>>
>> +static inline unsigned int kvm_arch_pv_features(void)
>> +{
>> + return 0;
>> +}
>> +
>> #endif
>>
>> #endif
>> diff --git a/arch/powerpc/include/asm/kvm_para.h b/arch/powerpc/include/asm/kvm_para.h
>> index c18916b..be81aac 100644
>> --- a/arch/powerpc/include/asm/kvm_para.h
>> +++ b/arch/powerpc/include/asm/kvm_para.h
>> @@ -211,6 +211,11 @@ static inline bool kvm_check_and_clear_guest_paused(void)
>> return false;
>> }
>>
>> +static inline unsigned int kvm_arch_pv_features(void)
>> +{
>> + return 0;
>> +}
>> +
>> #endif /* __KERNEL__ */
>>
>> #endif /* __POWERPC_KVM_PARA_H__ */
>> diff --git a/arch/s390/include/asm/kvm_para.h b/arch/s390/include/asm/kvm_para.h
>> index a988329..3d993b7 100644
>> --- a/arch/s390/include/asm/kvm_para.h
>> +++ b/arch/s390/include/asm/kvm_para.h
>> @@ -154,6 +154,11 @@ static inline bool kvm_check_and_clear_guest_paused(void)
>> return false;
>> }
>>
>> +static inline unsigned int kvm_arch_pv_features(void)
>> +{
>> + return 0;
>> +}
>> +
>> #endif
>>
>> #endif /* __S390_KVM_PARA_H */
>> diff --git a/arch/x86/include/asm/kvm_para.h b/arch/x86/include/asm/kvm_para.h
>> index 63ab166..c8ad86e 100644
>> --- a/arch/x86/include/asm/kvm_para.h
>> +++ b/arch/x86/include/asm/kvm_para.h
>> @@ -89,6 +89,8 @@ struct kvm_vcpu_pv_apf_data {
>> __u32 enabled;
>> };
>>
>> +#define KVM_PV_PORT (0x505UL)
>> +
>> #ifdef __KERNEL__
>> #include <asm/processor.h>
>>
>> @@ -221,6 +223,11 @@ static inline void kvm_disable_steal_time(void)
>> }
>> #endif
>>
>> +static inline unsigned int kvm_arch_pv_features(void)
>> +{
>> + return inl(KVM_PV_PORT);
>> +}
>> +
>> #endif /* __KERNEL__ */
>>
>> #endif /* _ASM_X86_KVM_PARA_H */
>> diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
>> index e554e5a..9a97f7e 100644
>> --- a/arch/x86/kernel/kvm.c
>> +++ b/arch/x86/kernel/kvm.c
>> @@ -328,6 +328,17 @@ static struct notifier_block kvm_pv_reboot_nb = {
>> .notifier_call = kvm_pv_reboot_notify,
>> };
>>
>> +static int
>> +kvm_pv_panic_notify(struct notifier_block *nb, unsigned long code, void *unused)
>> +{
>> + outl(KVM_PV_PANICKED, KVM_PV_PORT);
>> + return NOTIFY_DONE;
>> +}
>> +
>> +static struct notifier_block kvm_pv_panic_nb = {
>> + .notifier_call = kvm_pv_panic_notify,
>> +};
>> +
>> static u64 kvm_steal_clock(int cpu)
>> {
>> u64 steal;
>> @@ -414,6 +425,9 @@ void __init kvm_guest_init(void)
>>
>> paravirt_ops_setup();
>> register_reboot_notifier(&kvm_pv_reboot_nb);
>> + if (kvm_pv_has_feature(KVM_PV_FEATURE_PANICKED))
>> + atomic_notifier_chain_register(&panic_notifier_list,
>> + &kvm_pv_panic_nb);
>> for (i = 0; i < KVM_TASK_SLEEP_HASHSIZE; i++)
>> spin_lock_init(&async_pf_sleepers[i].lock);
>> if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF))
>> diff --git a/include/linux/kvm_para.h b/include/linux/kvm_para.h
>> index ff476dd..e73efcf 100644
>> --- a/include/linux/kvm_para.h
>> +++ b/include/linux/kvm_para.h
>> @@ -20,6 +20,12 @@
>> #define KVM_HC_FEATURES 3
>> #define KVM_HC_PPC_MAP_MAGIC_PAGE 4
>>
>> +/* The bit of the value read from KVM_PV_PORT */
>> +#define KVM_PV_FEATURE_PANICKED 0
>> +
>> +/* The value writen to KVM_PV_PORT */
>> +#define KVM_PV_PANICKED 1
>> +
>> /*
>> * hypercalls use architecture specific
>> */
>> @@ -33,5 +39,12 @@ static inline int kvm_para_has_feature(unsigned int feature)
>> return 1;
>> return 0;
>> }
>> +
>> +static inline int kvm_pv_has_feature(unsigned int feature)
>> +{
>> + if (kvm_arch_pv_features() & (1UL << feature))
>
> Reading from an invalid I/O port will return -1. So your test will
> deliver a wrong result on a platform that doesn't support this PV channel.
Yes, you are right. I will update it.
Thanks
Wen Congyang
>
> Jan
>
>> + return 1;
>> + return 0;
>> +}
>> #endif /* __KERNEL__ */
>> #endif /* __LINUX_KVM_PARA_H */
>>
>
>
>
>
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