Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A92C5C433F5 for ; Tue, 7 Dec 2021 07:51:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231528AbhLGHzS (ORCPT ); Tue, 7 Dec 2021 02:55:18 -0500 Received: from out30-44.freemail.mail.aliyun.com ([115.124.30.44]:44874 "EHLO out30-44.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230360AbhLGHzR (ORCPT ); Tue, 7 Dec 2021 02:55:17 -0500 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R191e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04423;MF=yun.wang@linux.alibaba.com;NM=1;PH=DS;RN=4;SR=0;TI=SMTPD_---0Uzjqu0m_1638863505; Received: from 30.21.164.179(mailfrom:yun.wang@linux.alibaba.com fp:SMTPD_---0Uzjqu0m_1638863505) by smtp.aliyun-inc.com(127.0.0.1); Tue, 07 Dec 2021 15:51:46 +0800 Message-ID: Date: Tue, 7 Dec 2021 15:51:45 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:91.0) Gecko/20100101 Thunderbird/91.2.1 Content-Language: en-US To: "Michael S. Tsirkin" , Jason Wang , "open list:VIRTIO CORE AND NET DRIVERS" , open list From: =?UTF-8?B?546L6LSH?= Subject: [RFC PATCH] virtio: make sure legacy pci device gain 32bit-pfn vq Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We observed issues like: virtio-pci 0000:14:00.0: platform bug: legacy virtio-mmio must not be used with RAM above 0x4000GB when we have a legacy pci device which desired 32bit-pfn vq but gain 64bit-pfn instead, lead into the failure of probe. vring_use_dma_api() is playing the key role in here, to help the allocation process understand which kind of vq it should alloc, however, it failed to take care the legacy pci device, which only have 32bit feature flag and can never have VIRTIO_F_ACCESS_PLATFORM setted. This patch introduce force_dma flag to help vring_use_dma_api() understanding the requirement better, to avoid the failing. Signed-off-by: Michael Wang --- drivers/virtio/virtio_pci_legacy.c | 10 ++++++++++ drivers/virtio/virtio_ring.c | 3 +++ include/linux/virtio.h | 1 + 3 files changed, 14 insertions(+) diff --git a/drivers/virtio/virtio_pci_legacy.c b/drivers/virtio/virtio_pci_legacy.c index d62e983..11f2ebf 100644 --- a/drivers/virtio/virtio_pci_legacy.c +++ b/drivers/virtio/virtio_pci_legacy.c @@ -263,6 +263,16 @@ int virtio_pci_legacy_probe(struct virtio_pci_device *vp_dev) vp_dev->setup_vq = setup_vq; vp_dev->del_vq = del_vq; + /* + * The legacy pci device requre 32bit-pfn vq, + * or setup_vq() will failed. + * + * Thus we make sure vring_use_dma_api() will + * return true during the allocation by marking + * force_dma here. + */ + vp_dev->vdev.force_dma = true; + return 0; err_iomap: diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index 3035bb6..6562e01 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -245,6 +245,9 @@ static inline bool virtqueue_use_indirect(struct virtqueue *_vq, static bool vring_use_dma_api(struct virtio_device *vdev) { + if (vdev->force_dma) + return true; + if (!virtio_has_dma_quirk(vdev)) return true; diff --git a/include/linux/virtio.h b/include/linux/virtio.h index 41edbc0..a4eb29d 100644 --- a/include/linux/virtio.h +++ b/include/linux/virtio.h @@ -109,6 +109,7 @@ struct virtio_device { bool failed; bool config_enabled; bool config_change_pending; + bool force_dma; spinlock_t config_lock; spinlock_t vqs_list_lock; /* Protects VQs list access */ struct device dev; -- 1.8.3.1