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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D57BEC433EF for ; Fri, 4 Mar 2022 01:19:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237543AbiCDBU2 (ORCPT ); Thu, 3 Mar 2022 20:20:28 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47504 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232623AbiCDBU0 (ORCPT ); Thu, 3 Mar 2022 20:20:26 -0500 Received: from mail-pj1-x1035.google.com (mail-pj1-x1035.google.com [IPv6:2607:f8b0:4864:20::1035]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 042E617B0F9 for ; Thu, 3 Mar 2022 17:19:40 -0800 (PST) Received: by mail-pj1-x1035.google.com with SMTP id cx5so6138176pjb.1 for ; Thu, 03 Mar 2022 17:19:39 -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=zEb5gJN0p3jp2prcQ3AxOX7oDu5JWoQts+UVDKAduE4=; b=W2B6Ck7YTcny7/5+zKdTiimZp2p9fdpezDQbNjt0oIfSoVxXTpdJGnk8L8e9MTUqwB 3gFzJjDJjyvW2GKsZLjwiGCrBbmfaPJzyEcPvhTDp7L4tTWEZc+Df7uC/yQtRkjyShLW GdTEGLqtdP/Zf5dDDhAD0FueSuMAFNJgd/bOtzE8daeam60uok4eGAeMZmEjuB355hZQ 8zS94v/ZFNklD/gVc6M870bWsiv8VzGlsHoDBc/YhrwWUGj6g2/3JIzDx8qGt+UCGaW2 Zr7h3T0vDzCJyckeMysXYMQt8cSKIyGAE0zqVkRIjtJX6byDEsp1GdloqwxcEs8wT+j6 b4uQ== 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=zEb5gJN0p3jp2prcQ3AxOX7oDu5JWoQts+UVDKAduE4=; b=GPiVVng/RWcgs5qp/RPoSTYTj6OXUDVVSaPPDaA/92xGC6ANb8uYAnWwsHERfOX1wE WLIcrQZMKIgIwa28UTnCvYxnHEQZI0YOr5uo2fWOVQcLk1cuw7HFSggkeYM3EnY93/sx /OM1CbxpbcuxVVKmVwcSkSBtkJ2sjsakK71NmFqISBcITR88EKo9LzTLjfCapk9Q0bj9 2ORG3W8A+u/dxXNbxJbdhmwcqcwd0rsSAiYTtObQLTWlZkqAXCIP1IqSJnPQDQYzCG8Z 1xrLSIG2rGsQS0sX8DxN3rFhsJzfzOdEsKUAbCSsraCQJV9JPNEqs5Anw+YU7/Cs4v2Z 0rZg== X-Gm-Message-State: AOAM530VWT52X8Yfi1MLt86QkT0PllfnuFwB7vT/V7U/yhYpYKvZ8uDL VJ7uG17EJQRkgDr8/WkmolZeow== X-Google-Smtp-Source: ABdhPJxzTz4pCEAh/l2V8XyzIwJXG5GRoE/ggM+ag3wUzlFXLIMu8qRnbVsUEia+MJuDOCYwqazwzg== X-Received: by 2002:a17:902:e889:b0:14f:c4bc:677b with SMTP id w9-20020a170902e88900b0014fc4bc677bmr39377392plg.68.1646356779252; Thu, 03 Mar 2022 17:19:39 -0800 (PST) Received: from google.com (226.75.127.34.bc.googleusercontent.com. [34.127.75.226]) by smtp.gmail.com with ESMTPSA id k17-20020a056a00135100b004f3a9a477d0sm3709376pfu.110.2022.03.03.17.19.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 03 Mar 2022 17:19:38 -0800 (PST) Date: Fri, 4 Mar 2022 01:19:35 +0000 From: Mingwei Zhang To: Paolo Bonzini Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , David Hildenbrand , David Matlack , Ben Gardon Subject: Re: [PATCH v4 19/30] KVM: x86/mmu: Do remote TLB flush before dropping RCU in TDP MMU resched Message-ID: References: <20220303193842.370645-1-pbonzini@redhat.com> <20220303193842.370645-20-pbonzini@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220303193842.370645-20-pbonzini@redhat.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 03, 2022, Paolo Bonzini wrote: > From: Sean Christopherson > > When yielding in the TDP MMU iterator, service any pending TLB flush > before dropping RCU protections in anticipation of using the caller's RCU > "lock" as a proxy for vCPUs in the guest. > > Signed-off-by: Sean Christopherson > Reviewed-by: Ben Gardon > Message-Id: <20220226001546.360188-19-seanjc@google.com> > Signed-off-by: Paolo Bonzini Reviewed-by: Mingwei Zhang > --- > arch/x86/kvm/mmu/tdp_mmu.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c > index c71debdbc732..3a866fcb5ea9 100644 > --- a/arch/x86/kvm/mmu/tdp_mmu.c > +++ b/arch/x86/kvm/mmu/tdp_mmu.c > @@ -716,11 +716,11 @@ static inline bool __must_check tdp_mmu_iter_cond_resched(struct kvm *kvm, > return false; > > if (need_resched() || rwlock_needbreak(&kvm->mmu_lock)) { > - rcu_read_unlock(); > - > if (flush) > kvm_flush_remote_tlbs(kvm); > > + rcu_read_unlock(); > + > if (shared) > cond_resched_rwlock_read(&kvm->mmu_lock); > else > -- > 2.31.1 > >