From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_NEOMUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DB2B5C43334 for ; Tue, 4 Sep 2018 00:46:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9446C20869 for ; Tue, 4 Sep 2018 00:46:29 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9446C20869 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726157AbeIDFJE (ORCPT ); Tue, 4 Sep 2018 01:09:04 -0400 Received: from mga14.intel.com ([192.55.52.115]:18906 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725811AbeIDFJD (ORCPT ); Tue, 4 Sep 2018 01:09:03 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga103.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 03 Sep 2018 17:46:26 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.53,327,1531810800"; d="scan'208";a="77713434" Received: from dbxu-mobl.ccr.corp.intel.com (HELO wfg-t570.sh.intel.com) ([10.254.212.218]) by FMSMGA003.fm.intel.com with ESMTP; 03 Sep 2018 17:46:23 -0700 Received: from wfg by wfg-t570.sh.intel.com with local (Exim 4.89) (envelope-from ) id 1fwzU5-0002DB-VY; Tue, 04 Sep 2018 08:46:21 +0800 Date: Tue, 4 Sep 2018 08:46:21 +0800 From: Fengguang Wu To: Christian Borntraeger Cc: Nikita Leshenko , akpm@linux-foundation.org, linux-mm@kvack.org, dongx.peng@intel.com, jingqi.liu@intel.com, eddie.dong@intel.com, dave.hansen@intel.com, ying.huang@intel.com, bgregg@netflix.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [RFC][PATCH 1/5] [PATCH 1/5] kvm: register in task_struct Message-ID: <20180904004621.aqhemgpefwtq3kif@wfg-t540p.sh.intel.com> References: <0ef9ccdc-3eae-f0b9-5304-8552cb94d166@de.ibm.com> <20180904002818.nq2ejxlsn4o34anl@wfg-t540p.sh.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <20180904002818.nq2ejxlsn4o34anl@wfg-t540p.sh.intel.com> User-Agent: NeoMutt/20170609 (1.8.3) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 04, 2018 at 08:28:18AM +0800, Fengguang Wu wrote: >Hi Christian and Nikita, > >On Mon, Sep 03, 2018 at 06:03:49PM +0200, Christian Borntraeger wrote: >> >> >>On 09/03/2018 04:10 PM, Nikita Leshenko wrote: >>> On September 2, 2018 5:21:15 AM, fengguang.wu@intel.com wrote: >>>> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c >>>> index 8b47507faab5..0c483720de8d 100644 >>>> --- a/virt/kvm/kvm_main.c >>>> +++ b/virt/kvm/kvm_main.c >>>> @@ -3892,6 +3892,7 @@ static void kvm_uevent_notify_change(unsigned int type, struct kvm *kvm) >>>> if (type == KVM_EVENT_CREATE_VM) { >>>> add_uevent_var(env, "EVENT=create"); >>>> kvm->userspace_pid = task_pid_nr(current); >>>> + current->kvm = kvm; >>> >>> Is it OK to store `kvm` on the task_struct? What if the thread that >>> originally created the VM exits? From the documentation it seems >>> like a VM is associated with an address space and not a specific >>> thread, so maybe it should be stored on mm_struct? >> >>Yes, ioctls accessing the kvm can happen from all threads. > >Good point, thank you for the tips! I'll move kvm pointer to mm_struct. > >>> From Documentation/virtual/kvm/api.txt: >>> Only run VM ioctls from the same process (address space) that was used >>> to create the VM. >>> >>> -Nikita Here it goes: diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 99ce070e7dcb..27c5446f3deb 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -27,6 +27,7 @@ typedef int vm_fault_t; struct address_space; struct mem_cgroup; struct hmm; +struct kvm; /* * Each physical page in the system has a struct page associated with @@ -489,10 +490,19 @@ struct mm_struct { /* HMM needs to track a few things per mm */ struct hmm *hmm; #endif +#if IS_ENABLED(CONFIG_KVM) + struct kvm *kvm; +#endif } __randomize_layout; extern struct mm_struct init_mm; +#if IS_ENABLED(CONFIG_KVM) +static inline struct kvm *mm_kvm(struct mm_struct *mm) { return mm->kvm; } +#else +static inline struct kvm *mm_kvm(struct mm_struct *mm) { return NULL; } +#endif + static inline void mm_init_cpumask(struct mm_struct *mm) { #ifdef CONFIG_CPUMASK_OFFSTACK diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 0c483720de8d..dca6156a7b35 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -3892,7 +3892,7 @@ static void kvm_uevent_notify_change(unsigned int type, struct kvm *kvm) if (type == KVM_EVENT_CREATE_VM) { add_uevent_var(env, "EVENT=create"); kvm->userspace_pid = task_pid_nr(current); - current->kvm = kvm; + current->mm->kvm = kvm; } else if (type == KVM_EVENT_DESTROY_VM) { add_uevent_var(env, "EVENT=destroy"); }