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=-0.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 7B2B1C2D0D0 for ; Tue, 24 Dec 2019 15:22:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5268C20706 for ; Tue, 24 Dec 2019 15:22:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="aqCGKHMS" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726256AbfLXPWv (ORCPT ); Tue, 24 Dec 2019 10:22:51 -0500 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:52184 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726178AbfLXPWv (ORCPT ); Tue, 24 Dec 2019 10:22:51 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1577200969; 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=MuI7b+nn3459lNvQkwSbmuvlvnSiMF65nG57H/ptVY8=; b=aqCGKHMSg0Dq51SuGimgMrNqN/GqJMzJv2hgbfNuvAXFtX0nFKI7D9b/TNDuPSoZ/yBXTQ vFFdfwhsRn2AzizwRzSvGw0rSU0whtJPdVSb/zoL3hUoLecceZ49AclW6Tb03KYFq6CDoy 9iBpvg66aWW8v43ReewHEO7/R6VbS30= Received: from mail-qt1-f197.google.com (mail-qt1-f197.google.com [209.85.160.197]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-4-KH_jnPcjMnqZgDX9eRbOmQ-1; Tue, 24 Dec 2019 10:22:48 -0500 X-MC-Unique: KH_jnPcjMnqZgDX9eRbOmQ-1 Received: by mail-qt1-f197.google.com with SMTP id l56so13173789qtk.11 for ; Tue, 24 Dec 2019 07:22:48 -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=MuI7b+nn3459lNvQkwSbmuvlvnSiMF65nG57H/ptVY8=; b=l86ihDEpbrX/9oIOVyIVVQYVbb2h5ehgkDws0d3X7jzkK62Qg3i6/p8B07v7RVoO4M n6ksUtNPUQ4W3h1gidrLTlMygr2CTb5B3NLkLq4ogDceeCz78I/ZKFzDt0OqS1kpL0Kf BG+dugbN68iTydebLJlwrjuJn57ButCgw5wsrHTe5uABG/tOb7s3y3OAZDsLM91HP1ke Q2Mn0HsG5peS6P2nd91rAAsUc4lN3q0GvsOXfntFIbgd/6wxqOyzEAWg5UMKD0q816RW 5Yeo+t+6jc//nQtTd4HaZY44jkL5vaVEh9ilkyx5LEBmtmeMMQVx9VoNhAO6nP/TwX1Z xYHw== X-Gm-Message-State: APjAAAXVG46C9MVPDqjhFtD6Tz99EQz9lPOtMghoVxbsq2MQBDsIoxPi 1LxW5oM3O0pYTOCGcc6t8+CsKb68MkPvcb9K4Sdl/zyp683zYaQCvf8XuhVHFvu2q3doKHb4VTy OzjC6aOvzk7Jaa+UdinQ0ABpx X-Received: by 2002:a05:620a:1014:: with SMTP id z20mr30191044qkj.196.1577200967805; Tue, 24 Dec 2019 07:22:47 -0800 (PST) X-Google-Smtp-Source: APXvYqxm9X0Ulp164MwCgzA6asjIcE8aiO1u/sC2ZnBoMfHFDI+t0HcMgrLoAcn6xNfXVagojVgfow== X-Received: by 2002:a05:620a:1014:: with SMTP id z20mr30191028qkj.196.1577200967586; Tue, 24 Dec 2019 07:22:47 -0800 (PST) Received: from xz-x1 ([2607:9880:19c0:3f::2]) by smtp.gmail.com with ESMTPSA id s11sm6954216qkg.99.2019.12.24.07.22.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 24 Dec 2019 07:22:46 -0800 (PST) Date: Tue, 24 Dec 2019 10:22:45 -0500 From: Peter Xu To: Jason Wang Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Dr David Alan Gilbert , Christophe de Dinechin , Sean Christopherson , Paolo Bonzini , "Michael S . Tsirkin" , Vitaly Kuznetsov Subject: Re: [PATCH RESEND v2 15/17] KVM: selftests: Add dirty ring buffer test Message-ID: <20191224152245.GA17176@xz-x1> References: <20191221020445.60476-1-peterx@redhat.com> <20191221020445.60476-5-peterx@redhat.com> <521fcdf6-db45-566d-7a83-e8c7a22cf7c5@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <521fcdf6-db45-566d-7a83-e8c7a22cf7c5@redhat.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Dec 24, 2019 at 02:18:37PM +0800, Jason Wang wrote: [...] > > + while (fetch != avail) { > > + cur = &dirty_gfns[fetch % TEST_DIRTY_RING_COUNT]; > > + TEST_ASSERT(cur->pad == 0, "Padding is non-zero: 0x%x", cur->pad); > > + TEST_ASSERT(cur->slot == slot, "Slot number didn't match: " > > + "%u != %u", cur->slot, slot); > > + TEST_ASSERT(cur->offset < num_pages, "Offset overflow: " > > + "0x%llx >= 0x%llx", cur->offset, num_pages); > > + DEBUG("fetch 0x%x offset 0x%llx\n", fetch, cur->offset); > > + test_and_set_bit(cur->offset, bitmap); > > + fetch++; > > > Any reason to use test_and_set_bit()? I guess set_bit() should be > sufficient. Yes. > > > > + count++; > > + } > > + WRITE_ONCE(indices->fetch_index, fetch); > > > Is WRITE_ONCE a must here? No. [...] > > +void *vcpu_map_dirty_ring(struct kvm_vm *vm, uint32_t vcpuid) > > +{ > > + struct vcpu *vcpu; > > + uint32_t size = vm->dirty_ring_size; > > + > > + TEST_ASSERT(size > 0, "Should enable dirty ring first"); > > + > > + vcpu = vcpu_find(vm, vcpuid); > > + > > + TEST_ASSERT(vcpu, "Cannot find vcpu %u", vcpuid); > > + > > + if (!vcpu->dirty_gfns) { > > + vcpu->dirty_gfns_count = size / sizeof(struct kvm_dirty_gfn); > > + vcpu->dirty_gfns = mmap(NULL, size, PROT_READ | PROT_WRITE, > > + MAP_SHARED, vcpu->fd, vm->page_size * > > + KVM_DIRTY_LOG_PAGE_OFFSET); > > > It looks to me that we don't write to dirty_gfn. > > So PROT_READ should be sufficient. Yes. Thanks, -- Peter Xu