From patchwork Wed Feb 3 23:37:03 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dongli Zhang X-Patchwork-Id: 12065755 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=-13.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 99B5AC433E0 for ; Wed, 3 Feb 2021 23:39:08 +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 43CB064F43 for ; Wed, 3 Feb 2021 23:39:08 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 43CB064F43 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=oracle.com 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.81094.149207 (Exim 4.92) (envelope-from ) id 1l7Rjg-00064G-O9; Wed, 03 Feb 2021 23:39:00 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 81094.149207; Wed, 03 Feb 2021 23:39:00 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1l7Rjg-00063X-Jf; Wed, 03 Feb 2021 23:39:00 +0000 Received: by outflank-mailman (input) for mailman id 81094; Wed, 03 Feb 2021 23:38:59 +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 1l7Rjf-00060K-GA for xen-devel@lists.xenproject.org; Wed, 03 Feb 2021 23:38:59 +0000 Received: from aserp2120.oracle.com (unknown [141.146.126.78]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id f5630453-ea40-4622-bde7-75818b1e8c84; Wed, 03 Feb 2021 23:38:53 +0000 (UTC) Received: from pps.filterd (aserp2120.oracle.com [127.0.0.1]) by aserp2120.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 113N8xlG103727; Wed, 3 Feb 2021 23:37:40 GMT Received: from aserp3020.oracle.com (aserp3020.oracle.com [141.146.126.70]) by aserp2120.oracle.com with ESMTP id 36cydm2q11-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 03 Feb 2021 23:37:40 +0000 Received: from pps.filterd (aserp3020.oracle.com [127.0.0.1]) by aserp3020.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 113NB3jw025155; Wed, 3 Feb 2021 23:37:40 GMT Received: from nam11-co1-obe.outbound.protection.outlook.com (mail-co1nam11lp2175.outbound.protection.outlook.com [104.47.56.175]) by aserp3020.oracle.com with ESMTP id 36dhc1wj19-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 03 Feb 2021 23:37:39 +0000 Received: from BYAPR10MB2663.namprd10.prod.outlook.com (2603:10b6:a02:a9::20) by SJ0PR10MB4784.namprd10.prod.outlook.com (2603:10b6:a03:2d4::22) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3805.19; Wed, 3 Feb 2021 23:37:36 +0000 Received: from BYAPR10MB2663.namprd10.prod.outlook.com ([fe80::b52e:bdd3:d193:4d14]) by BYAPR10MB2663.namprd10.prod.outlook.com ([fe80::b52e:bdd3:d193:4d14%7]) with mapi id 15.20.3805.026; Wed, 3 Feb 2021 23:37:36 +0000 Received: from localhost.localdomain (138.3.200.16) by CH0PR03CA0008.namprd03.prod.outlook.com (2603:10b6:610:b0::13) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3825.17 via Frontend Transport; Wed, 3 Feb 2021 23:37:31 +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" X-Inumbo-ID: f5630453-ea40-4622-bde7-75818b1e8c84 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : date : message-id : content-type : mime-version; s=corp-2020-01-29; bh=qsEGKVlwuthB6IlsIaAceDAu5rgeHIJP4Sy0WStKjL4=; b=YVQ3mdsiofTOsSsz6szMGB1tjZoyfyhYTGQuHfiuq9fnn7O+mT2ZMf/oFEeq9m6/1Ud8 o2l0M8hto7uYeKodKBVIBwQKP6dPH62mTjQrhTiRiwShRrcgkXTocWM10UTh5O8FaLzY cDm6mIFe4nrZ7wqdI5YrPfkPEWctS1yngSQqguMBRZpy9j3l72yZRsCmPLxckDD4ZdjL NemMVLhXDkv5uVNcDKgW0BhYnhrsw/SUIhuaT8VuFqxU0uatOGWiBOiSJC2SXIjYIKI3 1uu01zsQ4CYwqe/cQJp7tcQCzY9P4GR47cw5tuCu6lJ4ZDws6Y24EvMaRcipWL25/sIZ DQ== ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=aWsB8XXRpIpWWjUxGxaqItGk4rsX0gm4lOVAzXof6dvlDsAo6PxpE9LVo2mJYQX88GxxMz/SPPYnHAGjpnetONjUMHvWPYlNYB5+K8mECnmgGR/OgoGPDM7hinW4OtGlYoheUU6AQKW2+Gk7U8E1FWdigM4y8/WdKmg1ZXA1NMJmISTZVfGOUm01hX2hqlwZpi/LPdRyovi8ZZ0dEUk06oUAKSZeCOLU2gO7EuD9JFazPloB5l4xmm3xyelKDmdnUD472lImPCb5h8YLrO2J0ghn5gFY1O1d8ixBS2xgkqbiXNpB1/35t9gRaM4EmmPo7kkV52DZyOzrO3wvhXPuaA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=qsEGKVlwuthB6IlsIaAceDAu5rgeHIJP4Sy0WStKjL4=; b=e7pmhtT0iG6+1IPSSPrbtp/zCk+zXY4TfkNpxVkx2o+dJmQtno2dBbDYDmSSGy4EsndZFUkazg5pxHymYmOy+Ufp94V6WDZjkriVc4dbZnMrYkoExkxG+e3F+4e2JneeWDzhNj513lROwKlisWp3mYFb2ur40JI/0dX1lRh9DmEc+yRX+knwd1LO2EyVHo7J+YmlIQiaVkfCeMy+h0HW7BUUhM8vPfXWFf6Pqv36yAxYTDB+lHTtTHEpzUuKrJA/pVIdeub0rs/mu3UGaxeamjLNVoqbOQBavlIkYptqDChoBCtnbGnR2LRqn+Tud5yGPqQCONjQ4qzl/J6RL8KT5A== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=oracle.com; dmarc=pass action=none header.from=oracle.com; dkim=pass header.d=oracle.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.onmicrosoft.com; s=selector2-oracle-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=qsEGKVlwuthB6IlsIaAceDAu5rgeHIJP4Sy0WStKjL4=; b=cExWitoEK2u27ChY5w571nzM0Hj9zOqeABpvwhLDCdOdmoyNkuS9Pl9jgif4I26Ev2rVL2IO++rYmVZOJt/SwoVWVdXXhtpq3KnJ8ZwoCQpMEGpnkMChSKLJnq+ub5E5HpyN8sJzB0MxM1+FQQnpOjS3KgLuGx8xR2GIll4TFME= Authentication-Results: lists.freedesktop.org; dkim=none (message not signed) header.d=none;lists.freedesktop.org; dmarc=none action=none header.from=oracle.com; From: Dongli Zhang To: dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, iommu@lists.linux-foundation.org, linux-mips@vger.kernel.org, linux-mmc@vger.kernel.org, linux-pci@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, nouveau@lists.freedesktop.org, x86@kernel.org, xen-devel@lists.xenproject.org Cc: linux-kernel@vger.kernel.org, adrian.hunter@intel.com, akpm@linux-foundation.org, benh@kernel.crashing.org, bskeggs@redhat.com, bhelgaas@google.com, bp@alien8.de, boris.ostrovsky@oracle.com, hch@lst.de, chris@chris-wilson.co.uk, daniel@ffwll.ch, airlied@linux.ie, hpa@zytor.com, mingo@kernel.org, mingo@redhat.com, jani.nikula@linux.intel.com, joonas.lahtinen@linux.intel.com, jgross@suse.com, konrad.wilk@oracle.com, m.szyprowski@samsung.com, matthew.auld@intel.com, mpe@ellerman.id.au, rppt@kernel.org, paulus@samba.org, peterz@infradead.org, robin.murphy@arm.com, rodrigo.vivi@intel.com, sstabellini@kernel.org, bauerman@linux.ibm.com, tsbogend@alpha.franken.de, tglx@linutronix.de, ulf.hansson@linaro.org, joe.jin@oracle.com, thomas.lendacky@amd.com Subject: [PATCH RFC v1 0/6] swiotlb: 64-bit DMA buffer Date: Wed, 3 Feb 2021 15:37:03 -0800 Message-Id: <20210203233709.19819-1-dongli.zhang@oracle.com> X-Mailer: git-send-email 2.17.1 X-Originating-IP: [138.3.200.16] X-ClientProxiedBy: CH0PR03CA0008.namprd03.prod.outlook.com (2603:10b6:610:b0::13) To BYAPR10MB2663.namprd10.prod.outlook.com (2603:10b6:a02:a9::20) MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: aeb1ff20-7d9b-47ac-6403-08d8c89cafd9 X-MS-TrafficTypeDiagnostic: SJ0PR10MB4784: X-MS-Exchange-Transport-Forked: True X-Microsoft-Antispam-PRVS: X-MS-Oob-TLC-OOBClassifiers: OLM:10000; X-MS-Exchange-SenderADCheck: 1 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:BYAPR10MB2663.namprd10.prod.outlook.com;PTR:;CAT:NONE;SFS:(136003)(366004)(39860400002)(396003)(376002)(346002)(83380400001)(6666004)(316002)(5660300002)(956004)(66946007)(6506007)(86362001)(7406005)(1076003)(66476007)(8676002)(186003)(26005)(36756003)(7416002)(478600001)(2906002)(66556008)(8936002)(6486002)(16526019)(69590400011)(4326008)(6512007)(44832011)(921005)(2616005)(52116002);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData: 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 X-OriginatorOrg: oracle.com X-MS-Exchange-CrossTenant-Network-Message-Id: aeb1ff20-7d9b-47ac-6403-08d8c89cafd9 X-MS-Exchange-CrossTenant-AuthSource: BYAPR10MB2663.namprd10.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 03 Feb 2021 23:37:36.5357 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 4e2c6054-71cb-48f1-bd6c-3a9705aca71b X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: SjFAEv41/MntsA4fKs/ZtEmt2lYp+bejHO36bqzO1VLLyXuSm8FNEpw3/9n6Tfgy8/V89Pne75iBjlycVoHr+Q== X-MS-Exchange-Transport-CrossTenantHeadersStamped: SJ0PR10MB4784 X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=9884 signatures=668683 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 bulkscore=0 adultscore=0 suspectscore=0 spamscore=0 mlxscore=0 malwarescore=0 mlxlogscore=999 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2102030143 X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=9884 signatures=668683 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 bulkscore=0 adultscore=0 priorityscore=1501 impostorscore=0 malwarescore=0 clxscore=1011 spamscore=0 lowpriorityscore=0 phishscore=0 mlxlogscore=999 mlxscore=0 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2102030143 This RFC is to introduce the 2nd swiotlb buffer for 64-bit DMA access. The prototype is based on v5.11-rc6. The state of the art swiotlb pre-allocates <=32-bit memory in order to meet the DMA mask requirement for some 32-bit legacy device. Considering most devices nowadays support 64-bit DMA and IOMMU is available, the swiotlb is not used for most of times, except: 1. The xen PVM domain requires the DMA addresses to both (1) <= the device dma mask, and (2) continuous in machine address. Therefore, the 64-bit device may still require swiotlb on PVM domain. 2. From source code the AMD SME/SEV will enable SWIOTLB_FORCE. As a result it is always required to allocate from swiotlb buffer even the device dma mask is 64-bit. sme_early_init() -> if (sev_active()) swiotlb_force = SWIOTLB_FORCE; Therefore, this RFC introduces the 2nd swiotlb buffer for 64-bit DMA access. For instance, the swiotlb_tbl_map_single() allocates from the 2nd 64-bit buffer if the device DMA mask min_not_zero(*hwdev->dma_mask, hwdev->bus_dma_limit) is 64-bit. With the RFC, the Xen/AMD will be able to allocate >4GB swiotlb buffer. With it being 64-bit, you can (not in this patch set but certainly possible) allocate this at runtime. Meaning the size could change depending on the device MMIO buffers, etc. I have tested the patch set on Xen PVM dom0 boot via QEMU. The dom0 is boot via: qemu-system-x86_64 -smp 8 -m 20G -enable-kvm -vnc :9 \ -net nic -net user,hostfwd=tcp::5029-:22 \ -hda disk.img \ -device nvme,drive=nvme0,serial=deudbeaf1,max_ioqpairs=16 \ -drive file=test.qcow2,if=none,id=nvme0 \ -serial stdio The "swiotlb=65536,1048576,force" is to configure 32-bit swiotlb as 128MB and 64-bit swiotlb as 2048MB. The swiotlb is enforced. vm# cat /proc/cmdline placeholder root=UUID=4e942d60-c228-4caf-b98e-f41c365d9703 ro text swiotlb=65536,1048576,force quiet splash [ 5.119877] Booting paravirtualized kernel on Xen ... ... [ 5.190423] software IO TLB: Low Mem mapped [mem 0x0000000234e00000-0x000000023ce00000] (128MB) [ 6.276161] software IO TLB: High Mem mapped [mem 0x0000000166f33000-0x00000001e6f33000] (2048MB) 0x0000000234e00000 is mapped to 0x00000000001c0000 (32-bit machine address) 0x000000023ce00000-1 is mapped to 0x000000000ff3ffff (32-bit machine address) 0x0000000166f33000 is mapped to 0x00000004b7280000 (64-bit machine address) 0x00000001e6f33000-1 is mapped to 0x000000033a07ffff (64-bit machine address) While running fio for emulated-NVMe, the swiotlb is allocating from 64-bit io_tlb_used-highmem. vm# cat /sys/kernel/debug/swiotlb/io_tlb_nslabs 65536 vm# cat /sys/kernel/debug/swiotlb/io_tlb_used 258 vm# cat /sys/kernel/debug/swiotlb/io_tlb_nslabs-highmem 1048576 vm# cat /sys/kernel/debug/swiotlb/io_tlb_used-highmem 58880 I also tested virtio-scsi (with "disable-legacy=on,iommu_platform=true") on VM with AMD SEV enabled. qemu-system-x86_64 -enable-kvm -machine q35 -smp 36 -m 20G \ -drive if=pflash,format=raw,unit=0,file=OVMF_CODE.pure-efi.fd,readonly \ -drive if=pflash,format=raw,unit=1,file=OVMF_VARS.fd \ -hda ol7-uefi.qcow2 -serial stdio -vnc :9 \ -net nic -net user,hostfwd=tcp::5029-:22 \ -cpu EPYC -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=1 \ -machine memory-encryption=sev0 \ -device virtio-scsi-pci,id=scsi,disable-legacy=on,iommu_platform=true \ -device scsi-hd,drive=disk0 \ -drive file=test.qcow2,if=none,id=disk0,format=qcow2 The "swiotlb=65536,1048576" is to configure 32-bit swiotlb as 128MB and 64-bit swiotlb as 2048MB. We do not need to force swiotlb because AMD SEV will set SWIOTLB_FORCE. # cat /proc/cmdline BOOT_IMAGE=/vmlinuz-5.11.0-rc6swiotlb+ root=/dev/mapper/ol-root ro crashkernel=auto rd.lvm.lv=ol/root rd.lvm.lv=ol/swap rhgb quiet LANG=en_US.UTF-8 swiotlb=65536,1048576 [ 0.729790] AMD Memory Encryption Features active: SEV ... ... [ 2.113147] software IO TLB: Low Mem mapped [mem 0x0000000073e1e000-0x000000007be1e000] (128MB) [ 2.113151] software IO TLB: High Mem mapped [mem 0x00000004e8400000-0x0000000568400000] (2048MB) While running fio for virtio-scsi, the swiotlb is allocating from 64-bit io_tlb_used-highmem. vm# cat /sys/kernel/debug/swiotlb/io_tlb_nslabs 65536 vm# cat /sys/kernel/debug/swiotlb/io_tlb_used 0 vm# cat /sys/kernel/debug/swiotlb/io_tlb_nslabs-highmem 1048576 vm# cat /sys/kernel/debug/swiotlb/io_tlb_used-highmem 64647 Please let me know if there is any feedback for this idea and RFC. Dongli Zhang (6): swiotlb: define new enumerated type swiotlb: convert variables to arrays swiotlb: introduce swiotlb_get_type() to calculate swiotlb buffer type swiotlb: enable 64-bit swiotlb xen-swiotlb: convert variables to arrays xen-swiotlb: enable 64-bit xen-swiotlb arch/mips/cavium-octeon/dma-octeon.c | 3 +- arch/powerpc/kernel/dma-swiotlb.c | 2 +- arch/powerpc/platforms/pseries/svm.c | 8 +- arch/x86/kernel/pci-swiotlb.c | 5 +- arch/x86/pci/sta2x11-fixup.c | 2 +- drivers/gpu/drm/i915/gem/i915_gem_internal.c | 4 +- drivers/gpu/drm/i915/i915_scatterlist.h | 2 +- drivers/gpu/drm/nouveau/nouveau_ttm.c | 2 +- drivers/mmc/host/sdhci.c | 2 +- drivers/pci/xen-pcifront.c | 2 +- drivers/xen/swiotlb-xen.c | 123 ++++--- include/linux/swiotlb.h | 49 ++- kernel/dma/swiotlb.c | 382 +++++++++++++--------- 13 files changed, 363 insertions(+), 223 deletions(-) Thank you very much! Dongli Zhang