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 Received: from smtp1.osuosl.org (smtp1.osuosl.org [140.211.166.138]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B6C5BC433FE for ; Thu, 9 Dec 2021 15:45:32 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp1.osuosl.org (Postfix) with ESMTP id 50EA485439; Thu, 9 Dec 2021 15:45:32 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp1.osuosl.org ([127.0.0.1]) by localhost (smtp1.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id R3np7tctHNMd; Thu, 9 Dec 2021 15:45:31 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by smtp1.osuosl.org (Postfix) with ESMTPS id 38A4B8543B; Thu, 9 Dec 2021 15:45:31 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 131F2C001E; Thu, 9 Dec 2021 15:45:31 +0000 (UTC) Received: from smtp4.osuosl.org (smtp4.osuosl.org [IPv6:2605:bc80:3010::137]) by lists.linuxfoundation.org (Postfix) with ESMTP id 37EB8C0012 for ; Thu, 9 Dec 2021 15:45:30 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp4.osuosl.org (Postfix) with ESMTP id 18B7F422B0 for ; Thu, 9 Dec 2021 15:45:30 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Authentication-Results: smtp4.osuosl.org (amavisd-new); dkim=pass (2048-bit key) header.d=google.com Received: from smtp4.osuosl.org ([127.0.0.1]) by localhost (smtp4.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id nNzElOCzkgcq for ; Thu, 9 Dec 2021 15:45:29 +0000 (UTC) X-Greylist: whitelisted by SQLgrey-1.8.0 Received: from mail-pg1-x52c.google.com (mail-pg1-x52c.google.com [IPv6:2607:f8b0:4864:20::52c]) by smtp4.osuosl.org (Postfix) with ESMTPS id 86EFB422A7 for ; Thu, 9 Dec 2021 15:45:29 +0000 (UTC) Received: by mail-pg1-x52c.google.com with SMTP id m15so5394291pgu.11 for ; Thu, 09 Dec 2021 07:45:29 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=DMB6spvibGxVU/+VTs+sCniEDJa7q1WtFQnSMx4TKv0=; b=JL3ywlMl+rqRWktZIQaSKNPRmDzI/JO3XCKiJ8r7GZIJxKRbuMrdFvJsbWt1pYioh9 josJ5RJh5Y7Gyd5B1O4mVdtBWDNnScai+DDi5wWJSYT2NFXcDASTnNem11dZihnx5dgI 5O8EEPZhSK8bche/ll7QO96eeHWRqH3SaozruBdVk6+2nMJ2qDDNNWWvIU2HLyMU70UE 6L9viCV8FiEWMQtB4VxXBEyefmhmBVeEERG/AfMc+wu+/rM/NbrrxDKgd2fzbiUODYOc HFj2lkeeIM06mojzvzfu3yDjvsVAmtVLVsuaIdYN2RrouQl4LdB+8G8WqMk/sFE1rF9C 6C2g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=DMB6spvibGxVU/+VTs+sCniEDJa7q1WtFQnSMx4TKv0=; b=zNwImkZGfhZ48pG4youWjWdqa5GqYrTXMAYO9UNSifA47SaqfCiAgQxKGZTUDC0MQs oLgJOwHmLAuP5UnvZRvwyBJRocET7JuBId1DzzJ+aUh7/kHhV+o9rUI5zHuFzJS0NgX5 MfnxHYoFOngOmgsipKEsAOEPIjok4DUW5cU8/4Wi/VXM3QB512GqJRlDpWoReASrZP5F tt5AUiO721+MrxXw5I7dJfmS8aS+/FzKailIGkl4zGJwVT1JQUccfjUSx8I9K/8BzNu1 hnhzS3Mhmb5KMxli40w2RGpYTQcQm1gcXFNcOWCgg6J3vpSKiRNvlBmZKet3gIqUTnNR xcqw== X-Gm-Message-State: AOAM53277WNo68HNFT4NdyH0N9ttu7+udB0ttXQGBu4//SKOob+l2yXW kWcMnFTYTVkE++HBbJPgv2kUtQ== X-Google-Smtp-Source: ABdhPJzfr6ZOaNUFGkDN7LvTK2YY1tb9EksA+oA91YEVzv4A177yuuGRAMZuUgWC4VV06/F+8PoQbw== X-Received: by 2002:a05:6a00:2349:b0:4a8:d87:e8ad with SMTP id j9-20020a056a00234900b004a80d87e8admr12456531pfj.15.1639064728692; Thu, 09 Dec 2021 07:45:28 -0800 (PST) Received: from google.com (157.214.185.35.bc.googleusercontent.com. [35.185.214.157]) by smtp.gmail.com with ESMTPSA id ip5sm131157pjb.5.2021.12.09.07.45.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 09 Dec 2021 07:45:28 -0800 (PST) Date: Thu, 9 Dec 2021 15:45:24 +0000 To: Maxim Levitsky Subject: Re: [PATCH v3 00/26] KVM: x86: Halt and APICv overhaul Message-ID: References: <20211208015236.1616697-1-seanjc@google.com> <39c885fc6455dd0aa2f8643e725422851430f9ec.camel@redhat.com> <8c6c38f3cc201e42629c3b8e5cf8cdb251c9ea8d.camel@redhat.com> <3bf8d500-0c1e-92dd-20c8-c3c231d2cbed@redhat.com> <346f5a5e93077ba20188a9b0e67bb3a44e2cad48.camel@redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <346f5a5e93077ba20188a9b0e67bb3a44e2cad48.camel@redhat.com> Cc: Wanpeng Li , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, Paolo Bonzini , Vitaly Kuznetsov , Jim Mattson X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: Sean Christopherson via iommu Reply-To: Sean Christopherson Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" On Thu, Dec 09, 2021, Maxim Levitsky wrote: > On Thu, 2021-12-09 at 15:29 +0100, Paolo Bonzini wrote: > > On 12/9/21 01:02, Sean Christopherson wrote: > > > RDX, a.k.a. ir_data is NULL. This check in svm_ir_list_add() > > > > > > if (pi->ir_data && (pi->prev_ga_tag != 0)) { > > > > > > implies pi->ir_data can be NULL, but neither avic_update_iommu_vcpu_affinity() > > > nor amd_iommu_update_ga() check ir->data for NULL. > > > > > > amd_ir_set_vcpu_affinity() returns "success" without clearing pi.is_guest_mode > > > > > > /* Note: > > > * This device has never been set up for guest mode. > > > * we should not modify the IRTE > > > */ > > > if (!dev_data || !dev_data->use_vapic) > > > return 0; > > > > > > so it's plausible svm_ir_list_add() could add to the list with a NULL pi->ir_data. > > > > > > But none of the relevant code has seen any meaningful changes since 5.15, so odds > > > are good I broke something :-/ > > Doesn't reproduce here yet even with my iommu changes :-( > Oh well. Hmm, which suggests it could be an existing corner case. Based on the above, this seems prudent and correct: @@ -747,7 +754,7 @@ static int svm_ir_list_add(struct vcpu_svm *svm, struct amd_iommu_pi_data *pi) * so we need to check here if it's already been * added * to the ir_list. */ - if (pi->ir_data && (pi->prev_ga_tag != 0)) { + if (pi->prev_ga_tag != 0) { struct kvm *kvm = svm->vcpu.kvm; u32 vcpu_id = AVIC_GATAG_TO_VCPUID(pi->prev_ga_tag); struct kvm_vcpu *prev_vcpu = kvm_get_vcpu_by_id(kvm, vcpu_id); @@ -877,7 +884,7 @@ int svm_update_pi_irte(struct kvm *kvm, unsigned int host_irq, * we can reference to them directly when we update vcpu * scheduling information in IOMMU irte. */ - if (!ret && pi.is_guest_mode) + if (!ret && pi.is_guest_mode && pi.ir_data) svm_ir_list_add(svm, &pi); } else { /* Use legacy mode in IRTE */ @@ -898,7 +905,7 @@ int svm_update_pi_irte(struct kvm *kvm, unsigned int host_irq, * was cached. If so, we need to clean up the per-vcpu * ir_list. */ - if (!ret && pi.prev_ga_tag) { + if (!ret && pi.prev_ga_tag && !WARN_ON(!pi.ir_data)) { int id = AVIC_GATAG_TO_VCPUID(pi.prev_ga_tag); struct kvm_vcpu *vcpu; _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu