From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini Subject: Re: [PATCH 1/2] KVM: page track: add a new notifier type: track_flush_slot Date: Mon, 10 Oct 2016 20:32:11 +0200 Message-ID: References: <1475998904-13456-1-git-send-email-xiaoguang.chen@intel.com> <1475998904-13456-2-git-send-email-xiaoguang.chen@intel.com> <20161009083134.GA19090@nvidia.com> <20161010180140.GA27757@nvidia.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org, guangrong.xiao@intel.com, jike.song@intel.com, Kirti Wankhede To: Neo Jia , Xiaoguang Chen Return-path: Received: from mx1.redhat.com ([209.132.183.28]:55402 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751598AbcJJScZ (ORCPT ); Mon, 10 Oct 2016 14:32:25 -0400 In-Reply-To: <20161010180140.GA27757@nvidia.com> Sender: kvm-owner@vger.kernel.org List-ID: On 10/10/2016 20:01, Neo Jia wrote: >> Hi Neo, >> >> AFAIK this is needed because KVMGT doesn't paravirtualize the PPGTT, >> while nVidia does. > > Hi Paolo and Xiaoguang, > > I am just wondering how device driver can register a notifier so he can be > notified for write-protected pages when writes are happening. It can't yet, but the API is ready for that. kvm_vfio_set_group is currently where a struct kvm_device* and struct vfio_group* touch. Given a struct kvm_device*, dev->kvm provides the struct kvm to be passed to kvm_page_track_register_notifier. So I guess you could add a callback that passes the struct kvm_device* to the mdev device. Xiaoguang and Guangrong, what were your plans? We discussed it briefly at KVM Forum but I don't remember the details. Paolo > Thanks, > Neo > >> >> Paolo >> >>> Thanks, >>> Neo >>> >>>> >>>> Reviewed-by: Xiao Guangrong >>>> Signed-off-by: Chen Xiaoguang >>>> --- >>>> arch/x86/include/asm/kvm_page_track.h | 9 +++++++++ >>>> arch/x86/kvm/page_track.c | 25 +++++++++++++++++++++++++ >>>> arch/x86/kvm/x86.c | 2 +- >>>> 3 files changed, 35 insertions(+), 1 deletion(-) >>>> >>>> diff --git a/arch/x86/include/asm/kvm_page_track.h b/arch/x86/include/asm/kvm_page_track.h >>>> index c2b8d24..5f66597 100644 >>>> --- a/arch/x86/include/asm/kvm_page_track.h >>>> +++ b/arch/x86/include/asm/kvm_page_track.h >>>> @@ -32,6 +32,14 @@ struct kvm_page_track_notifier_node { >>>> */ >>>> void (*track_write)(struct kvm_vcpu *vcpu, gpa_t gpa, const u8 *new, >>>> int bytes); >>>> + /* >>>> + * It is called when memory slot is being moved or removed >>>> + * users can drop write-protection for the pages in that memory slot >>>> + * >>>> + * @kvm: the kvm where memory slot being moved or removed >>>> + * @slot: the memory slot being moved or removed >>>> + */ >>>> + void (*track_flush_slot)(struct kvm *kvm, struct kvm_memory_slot *slot); >>>> }; >>>> >>>> void kvm_page_track_init(struct kvm *kvm); >>>> @@ -58,4 +66,5 @@ kvm_page_track_unregister_notifier(struct kvm *kvm, >>>> struct kvm_page_track_notifier_node *n); >>>> void kvm_page_track_write(struct kvm_vcpu *vcpu, gpa_t gpa, const u8 *new, >>>> int bytes); >>>> +void kvm_page_track_flush_slot(struct kvm *kvm, struct kvm_memory_slot *slot); >>>> #endif >>>> diff --git a/arch/x86/kvm/page_track.c b/arch/x86/kvm/page_track.c >>>> index b431539..e79bb25 100644 >>>> --- a/arch/x86/kvm/page_track.c >>>> +++ b/arch/x86/kvm/page_track.c >>>> @@ -225,3 +225,28 @@ void kvm_page_track_write(struct kvm_vcpu *vcpu, gpa_t gpa, const u8 *new, >>>> n->track_write(vcpu, gpa, new, bytes); >>>> srcu_read_unlock(&head->track_srcu, idx); >>>> } >>>> + >>>> +/* >>>> + * Notify the node that memory slot is being removed or moved so that it can >>>> + * drop write-protection for the pages in the memory slot. >>>> + * >>>> + * The node should figure out it has any write-protected pages in this slot >>>> + * by itself. >>>> + */ >>>> +void kvm_page_track_flush_slot(struct kvm *kvm, struct kvm_memory_slot *slot) >>>> +{ >>>> + struct kvm_page_track_notifier_head *head; >>>> + struct kvm_page_track_notifier_node *n; >>>> + int idx; >>>> + >>>> + head = &kvm->arch.track_notifier_head; >>>> + >>>> + if (hlist_empty(&head->track_notifier_list)) >>>> + return; >>>> + >>>> + idx = srcu_read_lock(&head->track_srcu); >>>> + hlist_for_each_entry_rcu(n, &head->track_notifier_list, node) >>>> + if (n->track_flush_slot) >>>> + n->track_flush_slot(kvm, slot); >>>> + srcu_read_unlock(&head->track_srcu, idx); >>>> +} >>>> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c >>>> index 87f5dbb..f8ae90c 100644 >>>> --- a/arch/x86/kvm/x86.c >>>> +++ b/arch/x86/kvm/x86.c >>>> @@ -8278,7 +8278,7 @@ void kvm_arch_flush_shadow_all(struct kvm *kvm) >>>> void kvm_arch_flush_shadow_memslot(struct kvm *kvm, >>>> struct kvm_memory_slot *slot) >>>> { >>>> - kvm_mmu_invalidate_zap_all_pages(kvm); >>>> + kvm_page_track_flush_slot(kvm, slot); >>>> } >>>> >>>> static inline bool kvm_vcpu_has_events(struct kvm_vcpu *vcpu) >>>> -- >>>> 1.9.1 >>>> >>>> -- >>>> 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 kvm" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html