From patchwork Thu Mar 5 10:27:02 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Philippe_Mathieu-Daud=C3=A9?= X-Patchwork-Id: 11421523 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 E91E81580 for ; Thu, 5 Mar 2020 10:27:52 +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 7C1542073D for ; Thu, 5 Mar 2020 10:27:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Et00Ea/g" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7C1542073D 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]:46528 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j9njL-0000zY-4t for patchwork-qemu-devel@patchwork.kernel.org; Thu, 05 Mar 2020 05:27:51 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:44530) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j9nig-0000AR-Gb for qemu-devel@nongnu.org; Thu, 05 Mar 2020 05:27:11 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1j9nif-0007xx-5r for qemu-devel@nongnu.org; Thu, 05 Mar 2020 05:27:10 -0500 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:54485 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1j9nif-0007xF-2e for qemu-devel@nongnu.org; Thu, 05 Mar 2020 05:27:09 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1583404028; 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; bh=glnZh63agBY9jTgHy4oFd+qzRVfbjw7LMtpKPPibQwY=; b=Et00Ea/glSg9N/7SiSsf1HXMnWMqSrEQPI95S8DF4LlxJwcrxL392Nqos0Wojnw9k+cgID 9j5Cr1ARkz2PgOl+7d8x1FgEqRydv8P8/zKTqPhOGEaxwrblfcEZpgEYO+ATeYGjHc2Kfx rwiUwLG0Q4AuE/WGawM4pcnqfFm5Uks= Received: from mail-ed1-f71.google.com (mail-ed1-f71.google.com [209.85.208.71]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-481-jDxm7FTJPgGNFp3NVrgi6A-1; Thu, 05 Mar 2020 05:27:06 -0500 X-MC-Unique: jDxm7FTJPgGNFp3NVrgi6A-1 Received: by mail-ed1-f71.google.com with SMTP id g26so2714234edj.17 for ; Thu, 05 Mar 2020 02:27:06 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=tlYR1W8zAZXcdKzJjizsFD/7Jmu1H/2LfMgVC3H1d9M=; b=stNT+/8uQ5Sr1R7+Lg+Ab+0KY8TVe0U6s06Y67ZOsfEqgvySyTSIpfa2UxR3x0D3pC ZEss2FGw2tyDDIXkMrJ5koFqZl1C+vhKQ/C/WgScPsIxa+sfs4s5UoK5v95CkoGaV3wt 1mDfya/Dd2r1A8ZND4EjwOxqdVQUDjTjErAbqKmz+ACA9XdoiBZaE3BpI5G28zA0wEPZ T4DFF81fTUv08VHp3oUxZWQyJGmhhw2QC8MuojeqC+s024wZ9MmqHl3nSyol9P8Z7swl pH+fJYlbpWKzrPO1Mr21nL/JCEP2eyv+WutIXNuPoBNLRNNnD+Wsd54O+xbxOI99sflT tdlQ== X-Gm-Message-State: ANhLgQ2PfeNVzRavF0trrZQxKpJYb1k+xDQz11O6obXyVU22u3inVZd4 U4TyJ+ZyGA+sv2lGMxTXH8ee5+k/us9yY+1EBd5wmqYAvU5fwIKLcIgZMpoOvFJjTYSv8xcjsWb 56Mo8eASa4CCayzg= X-Received: by 2002:a05:6402:1481:: with SMTP id e1mr7536897edv.219.1583404025261; Thu, 05 Mar 2020 02:27:05 -0800 (PST) X-Google-Smtp-Source: ADFU+vvCWVROkqixQzTZ5oXhvzzm2LLJyWWOo1alqJISLP5GP2X9Ktr5PVSfzKA+1q45rTlehYcP/g== X-Received: by 2002:a05:6402:1481:: with SMTP id e1mr7536865edv.219.1583404025033; Thu, 05 Mar 2020 02:27:05 -0800 (PST) Received: from localhost.localdomain (47.red-88-21-205.staticip.rima-tde.net. [88.21.205.47]) by smtp.gmail.com with ESMTPSA id f25sm1858980edt.73.2020.03.05.02.27.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 05 Mar 2020 02:27:04 -0800 (PST) From: =?utf-8?q?Philippe_Mathieu-Daud=C3=A9?= To: qemu-devel@nongnu.org Subject: [PATCH v4] hw/i386/intel_iommu: Simplify vtd_find_as_from_bus_num() logic Date: Thu, 5 Mar 2020 11:27:02 +0100 Message-Id: <20200305102702.31512-1-philmd@redhat.com> X-Mailer: git-send-email 2.21.1 MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.120 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: Liu Yi L , Yi Sun , Eduardo Habkost , "Michael S. Tsirkin" , qemu-trivial@nongnu.org, Peter Xu , Eric Auger , Paolo Bonzini , =?utf-8?q?Philippe_Mathieu-Daud=C3=A9?= , Richard Henderson Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" The vtd_find_as_from_bus_num() function was introduced (in commit dbaabb25f) in a code format that could return an incorrect pointer, which was later fixed by commit a2e1cd41ccf. We could have avoided this by writing the if() statement differently. Do it now, in case this function is re-used. The code is easier to review (harder to miss bugs). Reviewed-by: Peter Xu Reviewed-by: Eric Auger Signed-off-by: Philippe Mathieu-Daudé Reviewed-by: Michael S. Tsirkin --- Since v1: Re-worded commit description, patch sent without -w. Since v2: patch send without diff Since v3: Fix typo in description and comment (Eric Auger) This patch is easier to review with 'git-diff -w' (--ignore-all-space) --- hw/i386/intel_iommu.c | 34 ++++++++++++++++++---------------- 1 file changed, 18 insertions(+), 16 deletions(-) diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c index 6258c58ac9..204b6841ec 100644 --- a/hw/i386/intel_iommu.c +++ b/hw/i386/intel_iommu.c @@ -987,24 +987,26 @@ static bool vtd_slpte_nonzero_rsvd(uint64_t slpte, uint32_t level) static VTDBus *vtd_find_as_from_bus_num(IntelIOMMUState *s, uint8_t bus_num) { VTDBus *vtd_bus = s->vtd_as_by_bus_num[bus_num]; - if (!vtd_bus) { - /* - * Iterate over the registered buses to find the one which - * currently hold this bus number, and update the bus_num - * lookup table: - */ - GHashTableIter iter; + GHashTableIter iter; - g_hash_table_iter_init(&iter, s->vtd_as_by_busptr); - while (g_hash_table_iter_next(&iter, NULL, (void **)&vtd_bus)) { - if (pci_bus_num(vtd_bus->bus) == bus_num) { - s->vtd_as_by_bus_num[bus_num] = vtd_bus; - return vtd_bus; - } - } - vtd_bus = NULL; + if (vtd_bus) { + return vtd_bus; } - return vtd_bus; + + /* + * Iterate over the registered buses to find the one which + * currently holds this bus number and update the bus_num + * lookup table. + */ + g_hash_table_iter_init(&iter, s->vtd_as_by_busptr); + while (g_hash_table_iter_next(&iter, NULL, (void **)&vtd_bus)) { + if (pci_bus_num(vtd_bus->bus) == bus_num) { + s->vtd_as_by_bus_num[bus_num] = vtd_bus; + return vtd_bus; + } + } + + return NULL; } /* Given the @iova, get relevant @slptep. @slpte_level will be the last level