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 9BEEFC433EF for ; Thu, 3 Mar 2022 18:08:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232882AbiCCSJj (ORCPT ); Thu, 3 Mar 2022 13:09:39 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44410 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230239AbiCCSJh (ORCPT ); Thu, 3 Mar 2022 13:09:37 -0500 Received: from mail-pg1-x530.google.com (mail-pg1-x530.google.com [IPv6:2607:f8b0:4864:20::530]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9F7CBE0A2A for ; Thu, 3 Mar 2022 10:08:51 -0800 (PST) Received: by mail-pg1-x530.google.com with SMTP id w37so5220918pga.7 for ; Thu, 03 Mar 2022 10:08:51 -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=BTYLb9HBGbhFly2fPG2qXLCkv8yykoYepo3XTTdlldU=; b=hMNEn/GbmsMUtg4oxmhbIXRQPVu7NbT/WnAC+/jn+WiRKSM7xs9ti7I+wV1P4R2KS6 WyVaAQBYn8vI35ur6gZJAJaQMN+WKs4MtDZsOsg3sgrnOB+a+83MvWTlsNKCDHwTbVNs AuNKx6JVDpCoQvMOaz4KETYS9boMeymCUkhtZW9QSbQ3vdqakdm//NbGnRRYgYv3Z0lq puUAUv3NNNaHd8SeCesRLc/m6vEaOpcbH3NUoLG6sfuyIVCzVUldPEUSFQcO3DYJfflj QgUdSyRbbMGqeQvDzGYp75lw3LygYoCXG/K8Uc9iyIT3sBJVfDqdm7XqMMwDJnTAqIMZ jMfw== 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=BTYLb9HBGbhFly2fPG2qXLCkv8yykoYepo3XTTdlldU=; b=5KYLG8vlVUd7Myc1W9k0lr1MbEzSjrH38y2C6+S0ZajdD7CoAtRN5gVsjllbiyfMd1 aEpczb78XtwEhVGyLA5hqKte6PKatwhkGW5Xu+vhfDUMGG8a6qvxqxFaZmPcqD3QUmfE W0J8lsEHDT+JOgi1DNqVL9CM77uEwJfdJrl+DAdw1CJfEo+XRC5BrhwTheOJSMzuVrVX D7BK+ntZr5S3MfHeqRXhOJu5u3A6dtYGMVJ+DP0ZZWqIJw7AIzeV5YNf56MM0ANrdPz3 qK1rEane6H7Igidf6mdtA8VVih//HgET6X7Mw+OfsGLw/pYGMfBgw3/CuNdahJNLDGfa KSvQ== X-Gm-Message-State: AOAM531Fnrz+9BdSgI/NG1fs2J6BOZUGit/euewZ/PVZVbZEnHR7fD7f KjlPs3JBXO0200mKpJv6ANqGzw== X-Google-Smtp-Source: ABdhPJwI4iCgO48anf6OIfRvqNpdDFYISkBjKns/9buSsWxjNWb2URbn2Tq6d3Jp3jtY1wj0NOs/Lg== X-Received: by 2002:a63:1c14:0:b0:36b:28ef:f8ce with SMTP id c20-20020a631c14000000b0036b28eff8cemr31681899pgc.96.1646330930904; Thu, 03 Mar 2022 10:08:50 -0800 (PST) Received: from google.com (226.75.127.34.bc.googleusercontent.com. [34.127.75.226]) by smtp.gmail.com with ESMTPSA id 124-20020a621682000000b004f6a2e59a4dsm963540pfw.121.2022.03.03.10.08.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 03 Mar 2022 10:08:50 -0800 (PST) Date: Thu, 3 Mar 2022 18:08:47 +0000 From: Mingwei Zhang To: Sean Christopherson Cc: Paolo Bonzini , Christian Borntraeger , Janosch Frank , Claudio Imbrenda , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , David Hildenbrand , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, David Matlack , Ben Gardon Subject: Re: [PATCH v3 08/28] KVM: x86/mmu: Batch TLB flushes from TDP MMU for MMU notifier change_spte Message-ID: References: <20220226001546.360188-1-seanjc@google.com> <20220226001546.360188-9-seanjc@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220226001546.360188-9-seanjc@google.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Feb 26, 2022, Sean Christopherson wrote: > Batch TLB flushes (with other MMUs) when handling ->change_spte() > notifications in the TDP MMU. The MMU notifier path in question doesn't > allow yielding and correcty flushes before dropping mmu_lock. nit: correctly > > Signed-off-by: Sean Christopherson > Reviewed-by: Ben Gardon Reviewed-by: Mingwei Zhang > --- > arch/x86/kvm/mmu/tdp_mmu.c | 13 ++++++------- > 1 file changed, 6 insertions(+), 7 deletions(-) > > diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c > index 848448b65703..634a2838e117 100644 > --- a/arch/x86/kvm/mmu/tdp_mmu.c > +++ b/arch/x86/kvm/mmu/tdp_mmu.c > @@ -1203,13 +1203,12 @@ static bool set_spte_gfn(struct kvm *kvm, struct tdp_iter *iter, > */ > bool kvm_tdp_mmu_set_spte_gfn(struct kvm *kvm, struct kvm_gfn_range *range) > { > - bool flush = kvm_tdp_mmu_handle_gfn(kvm, range, set_spte_gfn); > - > - /* FIXME: return 'flush' instead of flushing here. */ > - if (flush) > - kvm_flush_remote_tlbs_with_address(kvm, range->start, 1); > - > - return false; > + /* > + * No need to handle the remote TLB flush under RCU protection, the > + * target SPTE _must_ be a leaf SPTE, i.e. cannot result in freeing a > + * shadow page. See the WARN on pfn_changed in __handle_changed_spte(). > + */ > + return kvm_tdp_mmu_handle_gfn(kvm, range, set_spte_gfn); > } > > /* > -- > 2.35.1.574.g5d30c73bfb-goog >