From patchwork Fri Sep 11 08:20:27 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paul Durrant X-Patchwork-Id: 11769921 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 21CB8698 for ; Fri, 11 Sep 2020 08:21:37 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (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 D9A8C221E3 for ; Fri, 11 Sep 2020 08:21:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=xen.org header.i=@xen.org header.b="cz/HkwIx" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D9A8C221E3 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=xen.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1kGeIT-0006hu-7x; Fri, 11 Sep 2020 08:20:41 +0000 Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1kGeIS-0006hn-Dz for xen-devel@lists.xenproject.org; Fri, 11 Sep 2020 08:20:40 +0000 X-Inumbo-ID: 2b75d229-a94c-4e66-b652-64e129a36e96 Received: from mail.xenproject.org (unknown [104.130.215.37]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id 2b75d229-a94c-4e66-b652-64e129a36e96; Fri, 11 Sep 2020 08:20:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=xen.org; s=20200302mail; h=Content-Transfer-Encoding:MIME-Version:References: In-Reply-To:Message-Id:Date:Subject:Cc:To:From; bh=22FRfQNCAkwAjlVmLY20OL+Ek6oQxsoYvI5RGmP29So=; b=cz/HkwIxn91/N2lJGZGQtC1URn 8fG3zXMZjvFlXQCw7vwaBGzWByL6jAxaTQ1er/e6VQx+Yl3abLPNywjB/2deEuTKsoJ9PKvb+7FU0 sdWkkICSBMyJ3+rx01OkysdGCYVuumfX/JKCngRNxQPAkj625Cd+LkqwlOxH6gq2HPlg=; Received: from xenbits.xenproject.org ([104.239.192.120]) by mail.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1kGeIQ-0002tE-3c; Fri, 11 Sep 2020 08:20:38 +0000 Received: from host86-176-94-160.range86-176.btcentralplus.com ([86.176.94.160] helo=u2f063a87eabd5f.home) by xenbits.xenproject.org with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1kGeIP-0006YQ-Rx; Fri, 11 Sep 2020 08:20:38 +0000 From: Paul Durrant To: xen-devel@lists.xenproject.org Cc: Paul Durrant , Jan Beulich Subject: [PATCH v8 3/8] iommu: flush I/O TLB if iommu_map() or iommu_unmap() fail Date: Fri, 11 Sep 2020 09:20:27 +0100 Message-Id: <20200911082032.1466-4-paul@xen.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200911082032.1466-1-paul@xen.org> References: <20200911082032.1466-1-paul@xen.org> MIME-Version: 1.0 X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" From: Paul Durrant This patch adds a full I/O TLB flush to the error paths of iommu_map() and iommu_unmap(). Without this change callers need constructs such as: rc = iommu_map/unmap(...) err = iommu_flush(...) if ( !rc ) rc = err; With this change, it can be simplified to: rc = iommu_map/unmap(...) if ( !rc ) rc = iommu_flush(...) because, if the map or unmap fails the flush will be unnecessary. This saves a stack variable and generally makes the call sites tidier. Signed-off-by: Paul Durrant Reviewed-by: Jan Beulich --- v6: - Remove stray blank v5: - Avoid unnecessary flushing if 'page_order' is 0 - Add missing indirection on 'flush_flags' v2: - New in v2 --- xen/drivers/passthrough/iommu.c | 34 +++++++++++++++++---------------- 1 file changed, 18 insertions(+), 16 deletions(-) diff --git a/xen/drivers/passthrough/iommu.c b/xen/drivers/passthrough/iommu.c index 660dc5deb2..eb65631d59 100644 --- a/xen/drivers/passthrough/iommu.c +++ b/xen/drivers/passthrough/iommu.c @@ -274,6 +274,13 @@ int iommu_map(struct domain *d, dfn_t dfn, mfn_t mfn, break; } + /* + * Something went wrong so, if we were dealing with more than a single + * page, flush everything and clear flush flags. + */ + if ( page_order && unlikely(rc) && !iommu_iotlb_flush_all(d, *flush_flags) ) + *flush_flags = 0; + return rc; } @@ -283,14 +290,8 @@ int iommu_legacy_map(struct domain *d, dfn_t dfn, mfn_t mfn, unsigned int flush_flags = 0; int rc = iommu_map(d, dfn, mfn, page_order, flags, &flush_flags); - if ( !this_cpu(iommu_dont_flush_iotlb) ) - { - int err = iommu_iotlb_flush(d, dfn, (1u << page_order), - flush_flags); - - if ( !rc ) - rc = err; - } + if ( !this_cpu(iommu_dont_flush_iotlb) && !rc ) + rc = iommu_iotlb_flush(d, dfn, (1u << page_order), flush_flags); return rc; } @@ -330,6 +331,13 @@ int iommu_unmap(struct domain *d, dfn_t dfn, unsigned int page_order, } } + /* + * Something went wrong so, if we were dealing with more than a single + * page, flush everything and clear flush flags. + */ + if ( page_order && unlikely(rc) && !iommu_iotlb_flush_all(d, *flush_flags) ) + *flush_flags = 0; + return rc; } @@ -338,14 +346,8 @@ int iommu_legacy_unmap(struct domain *d, dfn_t dfn, unsigned int page_order) unsigned int flush_flags = 0; int rc = iommu_unmap(d, dfn, page_order, &flush_flags); - if ( !this_cpu(iommu_dont_flush_iotlb) ) - { - int err = iommu_iotlb_flush(d, dfn, (1u << page_order), - flush_flags); - - if ( !rc ) - rc = err; - } + if ( !this_cpu(iommu_dont_flush_iotlb) && !rc ) + rc = iommu_iotlb_flush(d, dfn, (1u << page_order), flush_flags); return rc; }