From patchwork Thu Oct 17 21:54:18 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Snow X-Patchwork-Id: 11197209 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id E370F912 for ; Thu, 17 Oct 2019 21:57:05 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id C1D132089C for ; Thu, 17 Oct 2019 21:57:05 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C1D132089C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Received: from localhost ([::1]:60894 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iLDlY-0000Uz-Cj for patchwork-qemu-devel@patchwork.kernel.org; Thu, 17 Oct 2019 17:57:04 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:60877) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iLDjS-0006mU-LP for qemu-devel@nongnu.org; Thu, 17 Oct 2019 17:54:55 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iLDjR-0002GQ-Dz for qemu-devel@nongnu.org; Thu, 17 Oct 2019 17:54:54 -0400 Received: from mx1.redhat.com ([209.132.183.28]:38898) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iLDjO-0002DE-2s; Thu, 17 Oct 2019 17:54:50 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 519243090FED; Thu, 17 Oct 2019 21:54:49 +0000 (UTC) Received: from probe.bos.redhat.com (dhcp-17-173.bos.redhat.com [10.18.17.173]) by smtp.corp.redhat.com (Postfix) with ESMTP id EEC985DE5B; Thu, 17 Oct 2019 21:54:47 +0000 (UTC) From: John Snow To: Peter Maydell , jsnow@redhat.com, qemu-devel@nongnu.org Subject: [PULL v3 01/19] util/hbitmap: strict hbitmap_reset Date: Thu, 17 Oct 2019 17:54:18 -0400 Message-Id: <20191017215436.14252-2-jsnow@redhat.com> In-Reply-To: <20191017215436.14252-1-jsnow@redhat.com> References: <20191017215436.14252-1-jsnow@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.43]); Thu, 17 Oct 2019 21:54:49 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Fam Zheng , Kevin Wolf , Vladimir Sementsov-Ogievskiy , qemu-block@nongnu.org, Juan Quintela , libvir-list@redhat.com, Markus Armbruster , "Dr. David Alan Gilbert" , Max Reitz , Stefan Hajnoczi Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" From: Vladimir Sementsov-Ogievskiy hbitmap_reset has an unobvious property: it rounds requested region up. It may provoke bugs, like in recently fixed write-blocking mode of mirror: user calls reset on unaligned region, not keeping in mind that there are possible unrelated dirty bytes, covered by rounded-up region and information of this unrelated "dirtiness" will be lost. Make hbitmap_reset strict: assert that arguments are aligned, allowing only one exception when @start + @count == hb->orig_size. It's needed to comfort users of hbitmap_next_dirty_area, which cares about hb->orig_size. Signed-off-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Max Reitz Message-Id: <20190806152611.280389-1-vsementsov@virtuozzo.com> [Maintainer edit: Max's suggestions from on-list. --js] [Maintainer edit: Eric's suggestion for aligned macro. --js] Signed-off-by: John Snow --- include/qemu/hbitmap.h | 5 +++++ tests/test-hbitmap.c | 2 +- util/hbitmap.c | 4 ++++ 3 files changed, 10 insertions(+), 1 deletion(-) diff --git a/include/qemu/hbitmap.h b/include/qemu/hbitmap.h index 4afbe6292e..1bf944ca3d 100644 --- a/include/qemu/hbitmap.h +++ b/include/qemu/hbitmap.h @@ -132,6 +132,11 @@ void hbitmap_set(HBitmap *hb, uint64_t start, uint64_t count); * @count: Number of bits to reset. * * Reset a consecutive range of bits in an HBitmap. + * @start and @count must be aligned to bitmap granularity. The only exception + * is resetting the tail of the bitmap: @count may be equal to hb->orig_size - + * @start, in this case @count may be not aligned. The sum of @start + @count is + * allowed to be greater than hb->orig_size, but only if @start < hb->orig_size + * and @start + @count = ALIGN_UP(hb->orig_size, granularity). */ void hbitmap_reset(HBitmap *hb, uint64_t start, uint64_t count); diff --git a/tests/test-hbitmap.c b/tests/test-hbitmap.c index eed5d288cb..e1f867085f 100644 --- a/tests/test-hbitmap.c +++ b/tests/test-hbitmap.c @@ -423,7 +423,7 @@ static void test_hbitmap_granularity(TestHBitmapData *data, hbitmap_test_check(data, 0); hbitmap_test_set(data, 0, 3); g_assert_cmpint(hbitmap_count(data->hb), ==, 4); - hbitmap_test_reset(data, 0, 1); + hbitmap_test_reset(data, 0, 2); g_assert_cmpint(hbitmap_count(data->hb), ==, 2); } diff --git a/util/hbitmap.c b/util/hbitmap.c index fd44c897ab..66db87c6ff 100644 --- a/util/hbitmap.c +++ b/util/hbitmap.c @@ -476,6 +476,10 @@ void hbitmap_reset(HBitmap *hb, uint64_t start, uint64_t count) /* Compute range in the last layer. */ uint64_t first; uint64_t last = start + count - 1; + uint64_t gran = 1ULL << hb->granularity; + + assert(QEMU_IS_ALIGNED(start, gran)); + assert(QEMU_IS_ALIGNED(count, gran) || (start + count == hb->orig_size)); trace_hbitmap_reset(hb, start, count, start >> hb->granularity, last >> hb->granularity);