From patchwork Wed Feb 17 14:24:57 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Julien Grall X-Patchwork-Id: 12091705 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=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 444BFC433E0 for ; Wed, 17 Feb 2021 14:25:27 +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 DB0DE64E4D for ; Wed, 17 Feb 2021 14:25:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DB0DE64E4D 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 list by lists.xenproject.org with outflank-mailman.86285.161885 (Exim 4.92) (envelope-from ) id 1lCNlO-0005Ln-Kf; Wed, 17 Feb 2021 14:25:10 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 86285.161885; Wed, 17 Feb 2021 14:25:10 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lCNlO-0005LS-At; Wed, 17 Feb 2021 14:25:10 +0000 Received: by outflank-mailman (input) for mailman id 86285; Wed, 17 Feb 2021 14:25:09 +0000 Received: from mail.xenproject.org ([104.130.215.37]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lCNlM-0005Jc-W0 for xen-devel@lists.xenproject.org; Wed, 17 Feb 2021 14:25:08 +0000 Received: from xenbits.xenproject.org ([104.239.192.120]) by mail.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lCNlL-0004eT-3C; Wed, 17 Feb 2021 14:25:07 +0000 Received: from 54-240-197-235.amazon.com ([54.240.197.235] helo=ufe34d9ed68d054.ant.amazon.com) by xenbits.xenproject.org with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1lCNlK-00057m-QC; Wed, 17 Feb 2021 14:25:07 +0000 X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=xen.org; s=20200302mail; h=References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From; bh=t6YsWVHT5mEBG6Q0BImhmwLAtI3B16h1jksP0n7ERIQ=; b=3uZES943amRECcWSte8d/Dw7R ooUX+hMcyyiJcd2+SiVkaL03GfOgZudyjNCtUsOlGFIAXRWUKX6zPL084P0mq3UBltQLNE3oIQNtO zRGebw4/RErIbC+mIgjphC42rG3SWLKaKVC/grLUGVeLLo8qTPRk6Fg09klw7eKzFDrbQ=; From: Julien Grall To: xen-devel@lists.xenproject.org Cc: hongyxia@amazon.co.uk, iwj@xenproject.org, Julien Grall , Jan Beulich , Andrew Cooper , Kevin Tian , Paul Durrant Subject: [for-4.15][PATCH v3 2/3] xen/x86: iommu: Ignore IOMMU mapping requests when a domain is dying Date: Wed, 17 Feb 2021 14:24:57 +0000 Message-Id: <20210217142458.3769-3-julien@xen.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20210217142458.3769-1-julien@xen.org> References: <20210217142458.3769-1-julien@xen.org> From: Julien Grall The new x86 IOMMU page-tables allocator will release the pages when relinquishing the domain resources. However, this is not sufficient when the domain is dying because nothing prevents page-table to be allocated. Currently page-table allocations can only happen from iommu_map(). As the domain is dying, there is no good reason to continue to modify the IOMMU page-tables. In order to observe d->is_dying correctly, we need to rely on per-arch locking, so the check to ignore IOMMU mapping is added on the per-driver map_page() callback. Signed-off-by: Julien Grall --- Changes in v3: - Patch added. This is a replacement of "xen/iommu: iommu_map: Don't crash the domain if it is dying" --- xen/drivers/passthrough/amd/iommu_map.c | 13 +++++++++++++ xen/drivers/passthrough/vtd/iommu.c | 13 +++++++++++++ xen/drivers/passthrough/x86/iommu.c | 3 +++ 3 files changed, 29 insertions(+) diff --git a/xen/drivers/passthrough/amd/iommu_map.c b/xen/drivers/passthrough/amd/iommu_map.c index d3a8b1aec766..ed78a083ba12 100644 --- a/xen/drivers/passthrough/amd/iommu_map.c +++ b/xen/drivers/passthrough/amd/iommu_map.c @@ -285,6 +285,19 @@ int amd_iommu_map_page(struct domain *d, dfn_t dfn, mfn_t mfn, spin_lock(&hd->arch.mapping_lock); + /* + * IOMMU mapping request can be safely ignored when the domain is dying. + * + * hd->arch.mapping_lock guarantees that d->is_dying will be observed + * before any page tables are freed (see iommu_free_pgtables() and + * iommu_clear_root_pgtable()). + */ + if ( d->is_dying ) + { + spin_unlock(&hd->arch.mapping_lock); + return 0; + } + rc = amd_iommu_alloc_root(d); if ( rc ) { diff --git a/xen/drivers/passthrough/vtd/iommu.c b/xen/drivers/passthrough/vtd/iommu.c index e1871f6c2bc1..239a63f74f64 100644 --- a/xen/drivers/passthrough/vtd/iommu.c +++ b/xen/drivers/passthrough/vtd/iommu.c @@ -1771,6 +1771,19 @@ static int __must_check intel_iommu_map_page(struct domain *d, dfn_t dfn, spin_lock(&hd->arch.mapping_lock); + /* + * IOMMU mapping request can be safely ignored when the domain is dying. + * + * hd->arch.mapping_lock guarantees that d->is_dying will be observed + * before any page tables are freed (see iommu_free_pgtables() and + * iommu_clear_root_pgtable()). + */ + if ( d->is_dying ) + { + spin_unlock(&hd->arch.mapping_lock); + return 0; + } + pg_maddr = addr_to_dma_page_maddr(d, dfn_to_daddr(dfn), 1); if ( !pg_maddr ) { diff --git a/xen/drivers/passthrough/x86/iommu.c b/xen/drivers/passthrough/x86/iommu.c index f54fc8093f18..faa0078db595 100644 --- a/xen/drivers/passthrough/x86/iommu.c +++ b/xen/drivers/passthrough/x86/iommu.c @@ -273,6 +273,9 @@ int iommu_free_pgtables(struct domain *d) /* * Pages will be moved to the free list below. So we want to * clear the root page-table to avoid any potential use after-free. + * + * After this call, no more IOMMU mapping can happen. + * */ hd->platform_ops->clear_root_pgtable(d);