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=-6.7 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,URIBL_BLACK, USER_AGENT_SANE_1 autolearn=ham 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 C1B54C41621 for ; Tue, 24 Mar 2020 13:28:29 +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 9053A20870 for ; Tue, 24 Mar 2020 13:28:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="EVXhHXsM" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9053A20870 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+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:48686 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jGjbY-0000vu-Lm for qemu-devel@archiver.kernel.org; Tue, 24 Mar 2020 09:28:28 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:49350) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jGjap-0000KB-33 for qemu-devel@nongnu.org; Tue, 24 Mar 2020 09:27:44 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1jGjan-0004PC-C6 for qemu-devel@nongnu.org; Tue, 24 Mar 2020 09:27:42 -0400 Received: from us-smtp-delivery-74.mimecast.com ([63.128.21.74]:59852) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1jGjan-0004Ok-94 for qemu-devel@nongnu.org; Tue, 24 Mar 2020 09:27:41 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1585056460; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=qQM1qktLiJWqpFLGAZZl1dYjShi0yrqWlHrQmoCG0+E=; b=EVXhHXsMsMr50nnzQVjwOxMryLvCptDUGAv2smy5h2Y83lViG8N3VuzqjBtDwZEGIJpZO6 G0wdldUHqa86k+Rp870+/3nX20KxnyJXTAQESBBxgvs93yH2ZJjY0o2NWyl6oc0bEEiWf0 1qKAk/93zFwvJr96CK/+sy0ezlYBYKE= Received: from mail-ed1-f72.google.com (mail-ed1-f72.google.com [209.85.208.72]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-232-CHx2QAEzOb2I76JYOvCYvg-1; Tue, 24 Mar 2020 09:27:39 -0400 X-MC-Unique: CHx2QAEzOb2I76JYOvCYvg-1 Received: by mail-ed1-f72.google.com with SMTP id m24so14803456edq.8 for ; Tue, 24 Mar 2020 06:27:38 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=qQM1qktLiJWqpFLGAZZl1dYjShi0yrqWlHrQmoCG0+E=; b=UFhwnpdRVnhSjnNprIfcyzMcB0CUIZa4/0o7Kz93aRhqKOx8KlLXbqmtzOQPO3X5v5 g/YwO/hfzmBdrnrEYY/NWOGWBaBORN3DvImY3lDHqotebnK7ZQ5tnycCoNDe1+k90coR EGvCfANleLKHI/1BYXDCd8gX+ttSiUeSoWvW+O6O1L5XZFLHrNGIWgdTbyJBwXjVf6qM vSkUWSCuGoPpzTE/qSYKXzMMaRnsuj69mlLXJM9fc59ETzhk2Np/aGclUQriD7PC4+/L N66ArXJ5B+6QmH5Iov10OO9D0jblp1hQrrVLFKaR2Oq0mu4oULp59OOrHBtQBpTiTD5x ALTQ== X-Gm-Message-State: ANhLgQ2NkdbSPgqMG2kSV4S8IBOBFSORyWUyjhlWBiaBSrr28rmwRdEp Fh6P9jNYNVvXxXJjuAtIeWJvZo/8/atasHXZVWNs/DHKu4YJud36X+D3gC6M9VU9Eb7E0OqiEHr POa/efBri+97ySZ4= X-Received: by 2002:a17:906:7083:: with SMTP id b3mr24711626ejk.238.1585056457733; Tue, 24 Mar 2020 06:27:37 -0700 (PDT) X-Google-Smtp-Source: ADFU+vvoCCOn0942HB7cO3eKw/stwMffoZuIXf8wIk9yxXdpyfLFBco6RhJwC9EMucZtUP6iJ2cgRw== X-Received: by 2002:a17:906:7083:: with SMTP id b3mr24711603ejk.238.1585056457476; Tue, 24 Mar 2020 06:27:37 -0700 (PDT) Received: from [192.168.1.35] (37.red-83-52-54.dynamicip.rima-tde.net. [83.52.54.37]) by smtp.gmail.com with ESMTPSA id t19sm1096289ejc.55.2020.03.24.06.27.36 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 24 Mar 2020 06:27:36 -0700 (PDT) Subject: Re: [PATCH qemu] vfio/spapr: Fix page size calculation To: Alexey Kardashevskiy , qemu-devel@nongnu.org References: <20200324063912.25063-1-aik@ozlabs.ru> From: =?UTF-8?Q?Philippe_Mathieu-Daud=c3=a9?= Message-ID: <87ddd733-8498-57a5-2fe2-8f1a3e60e0c9@redhat.com> Date: Tue, 24 Mar 2020 14:27:35 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 MIME-Version: 1.0 In-Reply-To: <20200324063912.25063-1-aik@ozlabs.ru> Content-Language: en-US X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 63.128.21.74 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: Alex Williamson , qemu-ppc@nongnu.org, David Gibson Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 3/24/20 7:39 AM, Alexey Kardashevskiy wrote: > Coverity detected an issue (CID 1421903) with potential call of clz64(0) > which returns 64 which make it do "<<" with a negative number. > > This checks the mask and avoids undefined behaviour. > > In practice pgsizes and memory_region_iommu_get_min_page_size() always > have some common page sizes and even if they did not, the resulting page > size would be 0x8000.0000.0000.0000 (gcc 9.2) and > ioctl(VFIO_IOMMU_SPAPR_TCE_CREATE) would fail anyway. > > Signed-off-by: Alexey Kardashevskiy > --- > hw/vfio/spapr.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/hw/vfio/spapr.c b/hw/vfio/spapr.c > index 33692fc86fd6..2900bd19417a 100644 > --- a/hw/vfio/spapr.c > +++ b/hw/vfio/spapr.c > @@ -147,7 +147,7 @@ int vfio_spapr_create_window(VFIOContainer *container, > { > int ret = 0; > IOMMUMemoryRegion *iommu_mr = IOMMU_MEMORY_REGION(section->mr); > - uint64_t pagesize = memory_region_iommu_get_min_page_size(iommu_mr); > + uint64_t pagesize = memory_region_iommu_get_min_page_size(iommu_mr), pgmask; > unsigned entries, bits_total, bits_per_level, max_levels; > struct vfio_iommu_spapr_tce_create create = { .argsz = sizeof(create) }; > long rampagesize = qemu_minrampagesize(); > @@ -159,8 +159,8 @@ int vfio_spapr_create_window(VFIOContainer *container, > if (pagesize > rampagesize) { > pagesize = rampagesize; > } > - pagesize = 1ULL << (63 - clz64(container->pgsizes & > - (pagesize | (pagesize - 1)))); > + pgmask = container->pgsizes & (pagesize | (pagesize - 1)); Is that ROUND_UP(container->pgsizes, pagesize)? > + pagesize = pgmask ? (1ULL << (63 - clz64(pgmask))) : 0; > if (!pagesize) { > error_report("Host doesn't support page size 0x%"PRIx64 > ", the supported mask is 0x%lx", >