Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030645Ab2B2BHr (ORCPT ); Tue, 28 Feb 2012 20:07:47 -0500 Received: from cn.fujitsu.com ([222.73.24.84]:63436 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1030609Ab2B2BHq (ORCPT ); Tue, 28 Feb 2012 20:07:46 -0500 Message-ID: <4F4D7AA4.3070801@cn.fujitsu.com> Date: Wed, 29 Feb 2012 09:08:52 +0800 From: Wen Congyang User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.9) Gecko/20100413 Fedora/3.0.4-2.fc13 Thunderbird/3.0.4 MIME-Version: 1.0 To: Gleb Natapov CC: Jan Kiszka , kvm list , Avi Kivity , KAMEZAWA Hiroyuki , "Daniel P. Berrange" , "linux-kernel@vger.kernel.org" , qemu-devel Subject: Re: [PATCH] kvm: notify host when guest paniced References: <4F4AF1FB.6000903@cn.fujitsu.com> <4F4B9C57.3010407@siemens.com> <4F4C8EEB.8040709@cn.fujitsu.com> <4F4C9F8C.1060901@siemens.com> <4F4CA17F.4020504@cn.fujitsu.com> <4F4CAA43.3020805@siemens.com> <20120228104528.GB24600@redhat.com> In-Reply-To: <20120228104528.GB24600@redhat.com> X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.1FP4|July 25, 2010) at 2012-02-29 09:05:55, Serialize by Router on mailserver/fnst(Release 8.5.1FP4|July 25, 2010) at 2012-02-29 09:05:57, Serialize complete at 2012-02-29 09:05:57 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4544 Lines: 120 At 02/28/2012 06:45 PM, Gleb Natapov Wrote: > On Tue, Feb 28, 2012 at 11:19:47AM +0100, Jan Kiszka wrote: >> On 2012-02-28 10:42, Wen Congyang wrote: >>> At 02/28/2012 05:34 PM, Jan Kiszka Wrote: >>>> On 2012-02-28 09:23, Wen Congyang wrote: >>>>> At 02/27/2012 11:08 PM, Jan Kiszka Wrote: >>>>>> On 2012-02-27 04:01, Wen Congyang wrote: >>>>>>> We can know the guest is paniced when the guest runs on xen. >>>>>>> But we do not have such feature on kvm. This patch implemnts >>>>>>> this feature, and the implementation is the same as xen: >>>>>>> register panic notifier, and call hypercall when the guest >>>>>>> is paniced. >>>>>>> >>>>>>> Signed-off-by: Wen Congyang >>>>>>> --- >>>>>>> arch/x86/kernel/kvm.c | 12 ++++++++++++ >>>>>>> arch/x86/kvm/svm.c | 8 ++++++-- >>>>>>> arch/x86/kvm/vmx.c | 8 ++++++-- >>>>>>> arch/x86/kvm/x86.c | 13 +++++++++++-- >>>>>>> include/linux/kvm.h | 1 + >>>>>>> include/linux/kvm_para.h | 1 + >>>>>>> 6 files changed, 37 insertions(+), 6 deletions(-) >>>>>>> >>>>>>> diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c >>>>>>> index f0c6fd6..b928d1d 100644 >>>>>>> --- a/arch/x86/kernel/kvm.c >>>>>>> +++ b/arch/x86/kernel/kvm.c >>>>>>> @@ -331,6 +331,17 @@ 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_hypercall0(KVM_HC_GUEST_PANIC); >>>>>>> + return NOTIFY_DONE; >>>>>>> +} >>>>>>> + >>>>>>> +static struct notifier_block kvm_pv_panic_nb = { >>>>>>> + .notifier_call = kvm_pv_panic_notify, >>>>>>> +}; >>>>>>> + >>>>>> >>>>>> You should split up host and guest-side changes. >>>>>> >>>>>>> static u64 kvm_steal_clock(int cpu) >>>>>>> { >>>>>>> u64 steal; >>>>>>> @@ -417,6 +428,7 @@ void __init kvm_guest_init(void) >>>>>>> >>>>>>> paravirt_ops_setup(); >>>>>>> register_reboot_notifier(&kvm_pv_reboot_nb); >>>>>>> + 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/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c >>>>>>> index 0b7690e..38b4705 100644 >>>>>>> --- a/arch/x86/kvm/svm.c >>>>>>> +++ b/arch/x86/kvm/svm.c >>>>>>> @@ -1900,10 +1900,14 @@ static int halt_interception(struct vcpu_svm *svm) >>>>>>> >>>>>>> static int vmmcall_interception(struct vcpu_svm *svm) >>>>>>> { >>>>>>> + int ret; >>>>>>> + >>>>>>> svm->next_rip = kvm_rip_read(&svm->vcpu) + 3; >>>>>>> skip_emulated_instruction(&svm->vcpu); >>>>>>> - kvm_emulate_hypercall(&svm->vcpu); >>>>>>> - return 1; >>>>>>> + ret = kvm_emulate_hypercall(&svm->vcpu); >>>>>>> + >>>>>>> + /* Ignore the error? */ >>>>>>> + return ret == 0 ? 0 : 1; >>>>>> >>>>>> Why can't kvm_emulate_hypercall return the right value? >>>>> >>>>> kvm_emulate_hypercall() will call kvm_hv_hypercall(), and >>>>> kvm_hv_hypercall() will return 0 when vcpu's CPL > 0. >>>>> If vcpu's CPL > 0, does kvm need to exit and tell it to >>>>> qemu? >>>> >>>> No, there is currently no exit to userspace due to hypercalls, neither >>>> of HV nor KVM kind. >>>> >>>> The point is that the return code of kvm_emulate_hypercall is unused so >>>> far, so you can easily redefine it to encode continue vs. exit to >>>> userspace. Once someone has different needs, this could still be >>>> refactored again. >>> >>> So, it is OK to change the return value of kvm_hv_hypercall() if vcpu's >>> CPL > 0? >> >> Yes, change it to encode what vendor modules need to return to their >> callers. >> > Better introduce new request flag and set it in your hypercall emulation. See > how triple fault is handled. triple fault sets KVM_EXIT_SHUTDOWN and exits to userspace. Do you mean introduce a new value(like KVM_EXIT_SHUTDOWN)? Thanks Wen Congyang > > -- > Gleb. > -- > 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/ > -- 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/