From nobody Tue Feb 10 03:56:14 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) client-ip=192.237.175.120; envelope-from=xen-devel-bounces@lists.xenproject.org; helo=lists.xenproject.org; Authentication-Results: mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) smtp.mailfrom=xen-devel-bounces@lists.xenproject.org ARC-Seal: i=1; a=rsa-sha256; t=1612884524; cv=none; d=zohomail.com; s=zohoarc; b=DFbm5LFQ738/55K4JAEilQvgye505qTe0H/DXliYfdmw9oj6v7QwSK9aEij7Cj6FUV2HjwCf4z29b6vBbpobDqsYh/BjZNVxiFN65T9F372XGiMODdkf0+4A4j4Vp/BsTPkrpkeJvf/88O4mdR6SmYBohBol6Jv8R5m7Z5R+p6I= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1612884524; h=Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Help:List-Unsubscribe:Message-ID:References:Sender:Subject:To; bh=Abq0PPrn9pqn8Kzw0uPNv4HuJCaFMRZ3qng4/qj2vjw=; b=YGhN19/CSik9C2qYG4O5IOX0HU8LHiw/fSw1LztA9EF1Cs4y65pVwvclf9uIqcnY+1v2ylQQuWMpHWhoQhY80WZPuUgw/cDgrhuX4+dP2fiqMKg2AALRXsUm7pzocNElDtxVaZrzlcfY7+geBxotmD2vTHXNa/iQLOtgL7rpIG4= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Return-Path: Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) by mx.zohomail.com with SMTPS id 1612884524485416.36029408072454; Tue, 9 Feb 2021 07:28:44 -0800 (PST) Received: from list by lists.xenproject.org with outflank-mailman.83288.154623 (Exim 4.92) (envelope-from ) id 1l9UwI-0007D3-TD; Tue, 09 Feb 2021 15:28:30 +0000 Received: by outflank-mailman (output) from mailman id 83288.154623; Tue, 09 Feb 2021 15:28:30 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1l9UwI-0007Cs-Oz; Tue, 09 Feb 2021 15:28:30 +0000 Received: by outflank-mailman (input) for mailman id 83288; Tue, 09 Feb 2021 15:28:29 +0000 Received: from mail.xenproject.org ([104.130.215.37]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1l9UwG-00078G-UV for xen-devel@lists.xenproject.org; Tue, 09 Feb 2021 15:28:28 +0000 Received: from xenbits.xenproject.org ([104.239.192.120]) by mail.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1l9UwG-0000u7-4T; Tue, 09 Feb 2021 15:28:28 +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 1l9UwF-0007gX-S3; Tue, 09 Feb 2021 15:28:28 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version 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=Abq0PPrn9pqn8Kzw0uPNv4HuJCaFMRZ3qng4/qj2vjw=; b=55TSYWVkX0xe7FrDVESrW/6UE wGYnGSpzg5Qa+uVM5TPcDzoPUoP6QyOgp9vgW6Bshv81L+xdL8+69NptC7B67BfIXHVGZiSNOL1RA EwItmCZkQc/HmjFAqTOI3cIyuryUcWT65XgCp10viS6zdWAN9m+UZrVWqi9e/M1gQUgfs=; From: Julien Grall To: xen-devel@lists.xenproject.org Cc: hongyxia@amazon.co.uk, iwj@xenproject.org, Julien Grall , Jan Beulich , Paul Durrant Subject: [for-4.15][PATCH v2 3/5] xen/iommu: iommu_map: Don't crash the domain if it is dying Date: Tue, 9 Feb 2021 15:28:14 +0000 Message-Id: <20210209152816.15792-4-julien@xen.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20210209152816.15792-1-julien@xen.org> References: <20210209152816.15792-1-julien@xen.org> X-ZohoMail-DKIM: pass (identity @xen.org) Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" From: Julien Grall It is a bit pointless to crash a domain that is already dying. This will become more an annoyance with a follow-up change where page-table allocation will be forbidden when the domain is dying. Security wise, there is no change as the devices would still have access to the IOMMU page-tables even if the domain has crashed until Xen start to relinquish the resources. For x86, we rely on dom_iommu(d)->arch.mapping.lock to ensure d->is_dying is correctly observed (a follow-up patch will held it in the relinquish path). For Arm, there is still a small race possible. But there is so far no failure specific to a domain dying. Signed-off-by: Julien Grall --- This was spotted when trying to destroy IOREQ servers while the domain is dying. The code will try to add the entry back in the P2M and therefore update the P2M (see arch_ioreq_server_disable() -> hvm_add_ioreq_gfn()). It should be possible to skip the mappin in hvm_add_ioreq_gfn(), however I didn't try a patch yet because checking d->is_dying can be racy (I can't find a proper lock). Changes in v2: - Patch added --- xen/drivers/passthrough/iommu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/xen/drivers/passthrough/iommu.c b/xen/drivers/passthrough/iomm= u.c index 879d238bcd31..75419f20f76d 100644 --- a/xen/drivers/passthrough/iommu.c +++ b/xen/drivers/passthrough/iommu.c @@ -272,7 +272,7 @@ int iommu_map(struct domain *d, dfn_t dfn, mfn_t mfn, flush_flags) ) continue; =20 - if ( !is_hardware_domain(d) ) + if ( !is_hardware_domain(d) && !d->is_dying ) domain_crash(d); =20 break; --=20 2.17.1