Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752429Ab2HMS5Z (ORCPT ); Mon, 13 Aug 2012 14:57:25 -0400 Received: from mx1.redhat.com ([209.132.183.28]:47145 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752194Ab2HMS5E (ORCPT ); Mon, 13 Aug 2012 14:57:04 -0400 Date: Mon, 13 Aug 2012 15:21:32 -0300 From: Marcelo Tosatti To: Wen Congyang Cc: kvm list , qemu-devel , "linux-kernel@vger.kernel.org" , Avi Kivity , "Daniel P. Berrange" , KAMEZAWA Hiroyuki , Jan Kiszka , Gleb Natapov Subject: Re: [PATCH v8] kvm: notify host when the guest is panicked Message-ID: <20120813182132.GB25268@amt.cnet> References: <5021D235.4050800@cn.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5021D235.4050800@cn.fujitsu.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8456 Lines: 298 On Wed, Aug 08, 2012 at 10:43:01AM +0800, 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 starting the kernel How about searching for the "Kernel panic - not syncing" string in the guests serial output? Say libvirtd could take an action upon that? Advantages: - It works for all architectures. - It does not depend on any virtual device. - It works as early as serial console output does (panics before that should be rare). - It allows you to see why the guest panicked. > Signed-off-by: Wen Congyang > --- > Documentation/virtual/kvm/pv_event.txt | 32 ++++++++++++++++++++++++++++++++ > arch/ia64/include/asm/kvm_para.h | 14 ++++++++++++++ > arch/powerpc/include/asm/kvm_para.h | 14 ++++++++++++++ > arch/s390/include/asm/kvm_para.h | 14 ++++++++++++++ > arch/x86/include/asm/kvm_para.h | 27 +++++++++++++++++++++++++++ > arch/x86/kernel/kvm.c | 25 +++++++++++++++++++++++++ > include/linux/kvm_para.h | 23 +++++++++++++++++++++++ > 7 files changed, 149 insertions(+), 0 deletions(-) > create mode 100644 Documentation/virtual/kvm/pv_event.txt > > diff --git a/Documentation/virtual/kvm/pv_event.txt b/Documentation/virtual/kvm/pv_event.txt > new file mode 100644 > index 0000000..0ebc890 > --- /dev/null > +++ b/Documentation/virtual/kvm/pv_event.txt > @@ -0,0 +1,32 @@ > +The KVM paravirtual event interface > +================================= > + > +Initializing the paravirtual event interface > +====================== > +kvm_pv_event_init() > +Argiments: > + None > + > +Return Value: > + 0 : The guest kernel can't use paravirtual event interface. > + -1: The guest kernel can use paravirtual event interface. > + > +Querying whether the event can be ejected > +====================== > +kvm_pv_has_feature() > +Arguments: > + feature: The bit value of this paravirtual event to query > + > +Return Value: > + 0: The guest kernel can't eject this paravirtual event. > + 1: The guest kernel can eject this paravirtual event. > + > + > +Ejecting paravirtual event > +====================== > +kvm_pv_eject_event() > +Arguments: > + event: The event to be ejected. > + > +Return Value: > + None > diff --git a/arch/ia64/include/asm/kvm_para.h b/arch/ia64/include/asm/kvm_para.h > index 2019cb9..b5ec658 100644 > --- a/arch/ia64/include/asm/kvm_para.h > +++ b/arch/ia64/include/asm/kvm_para.h > @@ -31,6 +31,20 @@ static inline bool kvm_check_and_clear_guest_paused(void) > return false; > } > > +static inline int kvm_arch_pv_event_init(void) > +{ > + return 0; > +} > + > +static inline unsigned int kvm_arch_pv_features(void) > +{ > + return 0; > +} > + > +static inline void kvm_arch_pv_eject_event(unsigned int event) > +{ > +} > + > #endif > > #endif > diff --git a/arch/powerpc/include/asm/kvm_para.h b/arch/powerpc/include/asm/kvm_para.h > index c18916b..01b98c7 100644 > --- a/arch/powerpc/include/asm/kvm_para.h > +++ b/arch/powerpc/include/asm/kvm_para.h > @@ -211,6 +211,20 @@ static inline bool kvm_check_and_clear_guest_paused(void) > return false; > } > > +static inline int kvm_arch_pv_event_init(void) > +{ > + return 0; > +} > + > +static inline unsigned int kvm_arch_pv_features(void) > +{ > + return 0; > +} > + > +static inline void kvm_arch_pv_eject_event(unsigned int event) > +{ > +} > + > #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 da44867..00ce058 100644 > --- a/arch/s390/include/asm/kvm_para.h > +++ b/arch/s390/include/asm/kvm_para.h > @@ -154,6 +154,20 @@ static inline bool kvm_check_and_clear_guest_paused(void) > return false; > } > > +static inline int kvm_arch_pv_event_init(void) > +{ > + return 0; > +} > + > +static inline unsigned int kvm_arch_pv_features(void) > +{ > + return 0; > +} > + > +static inline void kvm_arch_pv_eject_event(unsigned int event) > +{ > +} > + > #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 2f7712e..7d297f0 100644 > --- a/arch/x86/include/asm/kvm_para.h > +++ b/arch/x86/include/asm/kvm_para.h > @@ -96,8 +96,11 @@ struct kvm_vcpu_pv_apf_data { > #define KVM_PV_EOI_ENABLED KVM_PV_EOI_MASK > #define KVM_PV_EOI_DISABLED 0x0 > > +#define KVM_PV_EVENT_PORT (0x505UL) > + > #ifdef __KERNEL__ > #include > +#include > > extern void kvmclock_init(void); > extern int kvm_register_clock(char *txt); > @@ -228,6 +231,30 @@ static inline void kvm_disable_steal_time(void) > } > #endif > > +static inline int kvm_arch_pv_event_init(void) > +{ > + if (!request_region(KVM_PV_EVENT_PORT, 1, "KVM_PV_EVENT")) > + return -1; > + > + return 0; > +} > + > +static inline unsigned int kvm_arch_pv_features(void) > +{ > + unsigned int features = inl(KVM_PV_EVENT_PORT); > + > + /* Reading from an invalid I/O port will return -1 */ > + if (features == ~0) > + features = 0; > + > + return features; > +} > + > +static inline void kvm_arch_pv_eject_event(unsigned int event) > +{ > + outl(event, KVM_PV_EVENT_PORT); > +} > + > #endif /* __KERNEL__ */ > > #endif /* _ASM_X86_KVM_PARA_H */ > diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c > index c1d61ee..6129459 100644 > --- a/arch/x86/kernel/kvm.c > +++ b/arch/x86/kernel/kvm.c > @@ -368,6 +368,17 @@ 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) > +{ > + kvm_pv_eject_event(KVM_PV_EVENT_PANICKED); > + 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; > @@ -447,6 +458,20 @@ static void __init kvm_apf_trap_init(void) > set_intr_gate(14, &async_page_fault); > } > > +static void __init kvm_pv_panicked_event_init(void) > +{ > + if (!kvm_para_available()) > + return; > + > + if (kvm_pv_event_init()) > + return; > + > + if (kvm_pv_has_feature(KVM_PV_FEATURE_PANICKED)) > + atomic_notifier_chain_register(&panic_notifier_list, > + &kvm_pv_panic_nb); > +} > +arch_initcall(kvm_pv_panicked_event_init); > + > void __init kvm_guest_init(void) > { > int i; > diff --git a/include/linux/kvm_para.h b/include/linux/kvm_para.h > index ff476dd..8e0fb81 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 supported pv event */ > +#define KVM_PV_FEATURE_PANICKED 0 > + > +/* The pv event value */ > +#define KVM_PV_EVENT_PANICKED 1 > + > /* > * hypercalls use architecture specific > */ > @@ -33,5 +39,22 @@ static inline int kvm_para_has_feature(unsigned int feature) > return 1; > return 0; > } > + > +static inline int kvm_pv_event_init(void) > +{ > + return kvm_arch_pv_event_init(); > +} > + > +static inline int kvm_pv_has_feature(unsigned int feature) > +{ > + if (kvm_arch_pv_features() & (1UL << feature)) > + return 1; > + return 0; > +} > + > +static inline void kvm_pv_eject_event(unsigned int event) > +{ > + kvm_arch_pv_eject_event(event); > +} > #endif /* __KERNEL__ */ > #endif /* __LINUX_KVM_PARA_H */ > -- > 1.7.1 > > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/