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=-6.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 DA143C282DD for ; Thu, 9 Jan 2020 16:41:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AC4C520673 for ; Thu, 9 Jan 2020 16:41:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="MPF4eMLl" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387791AbgAIQlN (ORCPT ); Thu, 9 Jan 2020 11:41:13 -0500 Received: from us-smtp-2.mimecast.com ([207.211.31.81]:36874 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1733306AbgAIQlN (ORCPT ); Thu, 9 Jan 2020 11:41:13 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1578588072; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=W8is7aJP7Jr94Kau6TBpmvxbpseySDfgA2zeSyOzsAQ=; b=MPF4eMLl3AxOTUHxEmJnBnPjXPwPqPlmzNhlE5toXMPU9In+AKdKTEqot4SH1NTDEmWpY8 bUCZ3tk6usuHJA94fBP8vX0vnWmxeB0ZvwB2CR8OtjPyXcmRstMnvAglHlQxwtDAgzP+vt ru6JweDBGEFQdq5U0LjlXQsFTwqbuF8= Received: from mail-qv1-f69.google.com (mail-qv1-f69.google.com [209.85.219.69]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-417-pskfBW-eOQCUDgzMqOWhPg-1; Thu, 09 Jan 2020 11:41:06 -0500 X-MC-Unique: pskfBW-eOQCUDgzMqOWhPg-1 Received: by mail-qv1-f69.google.com with SMTP id e10so4447045qvq.18 for ; Thu, 09 Jan 2020 08:41:06 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=W8is7aJP7Jr94Kau6TBpmvxbpseySDfgA2zeSyOzsAQ=; b=bP5o6s++t05kzHNSYFsHYsh7CbAiOjlH3KbJFDikYJPvtjhIVtpkj/cBRVQaY07Py7 quQLhOQcL9K1T5+l+2o6Zc93mVl6vhU5KO3aXd1hJhC4hRro8/8UYsyhIirMzp30rgSt ji+eMlgFx5V3MZHM2dhUQJmv8D9zqcu8N4gHY95X1Dh4CSK9Tr5J0nisE3Q3bUbdfGPA s0mLWnBGo1g5ZpEXDQC+iBPHhOTuHNmUusPd4/0HLk0B2satb4tepviToSj+Js5QDAwm n7c1xk73VPyVxcM/Ui0+vGMsIHx80TzH+h+1kPbB4ozUZTIXrAw1wZeNUSqFp4n03s5C sWqQ== X-Gm-Message-State: APjAAAXeKbu4XgvEFF7hfcm//fQi1RXVpS1ap7g4qftZPGTGByLYh97r WovudtjbY/Yy9XXXToKXnMPZRu6zx8tg2jTthPxJ90SFZdFKc6toy2lgGZ9UDJh91LtFsAQjK4L sodSITz5V1B4TDtxMr5Xj7Ra7 X-Received: by 2002:a0c:d60e:: with SMTP id c14mr9518432qvj.76.1578588065793; Thu, 09 Jan 2020 08:41:05 -0800 (PST) X-Google-Smtp-Source: APXvYqwFThgj+FPfsa8kRdSVmK/1QdWGxewVr4WL/ID/MZzW7mYehsO2/EBPyUx+T7omkvmVW3Z1Gg== X-Received: by 2002:a0c:d60e:: with SMTP id c14mr9518407qvj.76.1578588065427; Thu, 09 Jan 2020 08:41:05 -0800 (PST) Received: from xz-x1 ([104.156.64.74]) by smtp.gmail.com with ESMTPSA id g16sm3237033qkk.61.2020.01.09.08.41.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 09 Jan 2020 08:41:04 -0800 (PST) Date: Thu, 9 Jan 2020 11:41:02 -0500 From: Peter Xu To: kvm@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Christophe de Dinechin , "Michael S . Tsirkin" , Paolo Bonzini , Sean Christopherson , Yan Zhao , Alex Williamson , Jason Wang , Kevin Kevin , Vitaly Kuznetsov , "Dr . David Alan Gilbert" Subject: Re: [PATCH v3 14/21] KVM: Don't allocate dirty bitmap if dirty ring is enabled Message-ID: <20200109164102.GA36997@xz-x1> References: <20200109145729.32898-1-peterx@redhat.com> <20200109145729.32898-15-peterx@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20200109145729.32898-15-peterx@redhat.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 09, 2020 at 09:57:22AM -0500, Peter Xu wrote: > Because kvm dirty rings and kvm dirty log is used in an exclusive way, > Let's avoid creating the dirty_bitmap when kvm dirty ring is enabled. > At the meantime, since the dirty_bitmap will be conditionally created > now, we can't use it as a sign of "whether this memory slot enabled > dirty tracking". Change users like that to check against the kvm > memory slot flags. > > Note that there still can be chances where the kvm memory slot got its > dirty_bitmap allocated, _if_ the memory slots are created before > enabling of the dirty rings and at the same time with the dirty > tracking capability enabled, they'll still with the dirty_bitmap. > However it should not hurt much (e.g., the bitmaps will always be > freed if they are there), and the real users normally won't trigger > this because dirty bit tracking flag should in most cases only be > applied to kvm slots only before migration starts, that should be far > latter than kvm initializes (VM starts). > > Signed-off-by: Peter Xu > --- > include/linux/kvm_host.h | 5 +++++ > virt/kvm/kvm_main.c | 5 +++-- > 2 files changed, 8 insertions(+), 2 deletions(-) > > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h > index c96161c6a0c9..ab2a169b1264 100644 > --- a/include/linux/kvm_host.h > +++ b/include/linux/kvm_host.h > @@ -353,6 +353,11 @@ struct kvm_memory_slot { > u8 as_id; > }; > > +static inline bool kvm_slot_dirty_track_enabled(struct kvm_memory_slot *slot) > +{ > + return slot->flags & KVM_MEM_LOG_DIRTY_PAGES; > +} > + > static inline unsigned long kvm_dirty_bitmap_bytes(struct kvm_memory_slot *memslot) > { > return ALIGN(memslot->npages, BITS_PER_LONG) / 8; > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index f0f766183cb2..46da3169944f 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -1120,7 +1120,8 @@ int __kvm_set_memory_region(struct kvm *kvm, > } > > /* Allocate page dirty bitmap if needed */ > - if ((new.flags & KVM_MEM_LOG_DIRTY_PAGES) && !new.dirty_bitmap) { > + if ((new.flags & KVM_MEM_LOG_DIRTY_PAGES) && !new.dirty_bitmap && > + !kvm->dirty_ring_size) { > if (kvm_create_dirty_bitmap(&new) < 0) > goto out_free; > } > @@ -2309,7 +2310,7 @@ static void mark_page_dirty_in_slot(struct kvm *kvm, > struct kvm_memory_slot *memslot, > gfn_t gfn) > { > - if (memslot && memslot->dirty_bitmap) { > + if (memslot && kvm_slot_dirty_track_enabled(memslot)) { > unsigned long rel_gfn = gfn - memslot->base_gfn; > u32 slot = (memslot->as_id << 16) | memslot->id; > > -- > 2.24.1 > I think below should be squashed as well into this patch: diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 621b842a9b7b..0806bd12d8ee 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -1308,7 +1308,7 @@ static inline bool memslot_valid_for_gpte(struct kvm_memory_slot *slot, { if (!slot || slot->flags & KVM_MEMSLOT_INVALID) return false; - if (no_dirty_log && slot->dirty_bitmap) + if (no_dirty_log && kvm_slot_dirty_track_enabled(slot)) return false; return true; Thanks, -- Peter Xu