From mboxrd@z Thu Jan 1 00:00:00 1970 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=-17.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 C713DC433ED for ; Wed, 28 Apr 2021 09:22:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 85E90613FB for ; Wed, 28 Apr 2021 09:22:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237685AbhD1JWn (ORCPT ); Wed, 28 Apr 2021 05:22:43 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:32267 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230113AbhD1JWm (ORCPT ); Wed, 28 Apr 2021 05:22:42 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1619601717; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=axU4olOyFNuAi1siDolpKEA8kn46+KAy0fVSsUFenIk=; b=VI08gX5lmE8LhskhHD71g3tihpYRSrIHUhX43HOV821vJS3TtKm8xFcWoV+RwCQBP0Bdxk YpvdPzmPWdk7eFdIEOyg6njH6XwZdeJ8Dk2orfysPzFc75b4FMbC2VxUPn4rE/hM6Fabai FV1vdzUUV1bUN10ei2Dg5+6w/rD+OUY= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-294-TqqIchBUMpmMqypacMgirw-1; Wed, 28 Apr 2021 05:21:54 -0400 X-MC-Unique: TqqIchBUMpmMqypacMgirw-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 9DA0B818CA3; Wed, 28 Apr 2021 09:21:53 +0000 (UTC) Received: from wangxiaodeMacBook-Air.local (ovpn-12-25.pek2.redhat.com [10.72.12.25]) by smtp.corp.redhat.com (Postfix) with ESMTP id 83A6A5C224; Wed, 28 Apr 2021 09:21:50 +0000 (UTC) Subject: Re: [PATCH 2/2] vDPA/ifcvf: implement doorbell mapping for ifcvf To: "Zhu, Lingshan" , mst@redhat.com Cc: virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org References: <20210428082133.6766-1-lingshan.zhu@intel.com> <20210428082133.6766-3-lingshan.zhu@intel.com> <5052fced-cd9a-e453-5cb2-39cdde60a208@intel.com> From: Jason Wang Message-ID: <1984491f-cd5e-d4bc-b328-41e2f2e935fd@redhat.com> Date: Wed, 28 Apr 2021 17:21:48 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.10.0 MIME-Version: 1.0 In-Reply-To: <5052fced-cd9a-e453-5cb2-39cdde60a208@intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 在 2021/4/28 下午4:59, Zhu, Lingshan 写道: > > > On 4/28/2021 4:42 PM, Jason Wang wrote: >> >> 在 2021/4/28 下午4:21, Zhu Lingshan 写道: >>> This commit implements doorbell mapping feature for ifcvf. >>> This feature maps the notify page to userspace, to eliminate >>> vmexit when kick a vq. >>> >>> Signed-off-by: Zhu Lingshan >>> --- >>>   drivers/vdpa/ifcvf/ifcvf_main.c | 18 ++++++++++++++++++ >>>   1 file changed, 18 insertions(+) >>> >>> diff --git a/drivers/vdpa/ifcvf/ifcvf_main.c >>> b/drivers/vdpa/ifcvf/ifcvf_main.c >>> index e48e6b74fe2e..afcb71bc0f51 100644 >>> --- a/drivers/vdpa/ifcvf/ifcvf_main.c >>> +++ b/drivers/vdpa/ifcvf/ifcvf_main.c >>> @@ -413,6 +413,23 @@ static int ifcvf_vdpa_get_vq_irq(struct >>> vdpa_device *vdpa_dev, >>>       return vf->vring[qid].irq; >>>   } >>>   +static struct vdpa_notification_area >>> ifcvf_get_vq_notification(struct vdpa_device *vdpa_dev, >>> +                                   u16 idx) >>> +{ >>> +    struct ifcvf_hw *vf = vdpa_to_vf(vdpa_dev); >>> +    struct vdpa_notification_area area; >>> + >>> +    if (vf->notify_pa % PAGE_SIZE) { >>> +        area.addr = 0; >>> +        area.size = 0; >> >> >> We don't need this since: >> >> 1) there's a check in the vhost vDPA > I think you mean this code block in vdpa.c >         notify = ops->get_vq_notification(vdpa, index); >         if (notify.addr & (PAGE_SIZE - 1)) >                 return -EINVAL; > > This should work, however, I think the parent driver should ensure it > passes a PAGE_SIZE aligned address to userspace, to be robust, to be > reliable. The point is parent is unaware of whether or not there's a userspace. >> 2) device is unaware of the bound driver, non page aligned doorbell >> doesn't necessarily meant it can be used > Yes, non page aligned doorbell can not be used, so there is a check. Typo, what I meant is "it can't be used". That is to say, we should let the vDPA bus driver to decide whether or not it can be used. Thanks > > Thanks > Zhu Lingshan >> >> Let's leave those polices to the driver. >> >> Thanks >> >> >>> +    } else { >>> +        area.addr = vf->notify_pa; >>> +        area.size = PAGE_SIZE; >>> +    } >>> + >>> +    return area; >>> +} >>> + >>>   /* >>>    * IFCVF currently does't have on-chip IOMMU, so not >>>    * implemented set_map()/dma_map()/dma_unmap() >>> @@ -440,6 +457,7 @@ static const struct vdpa_config_ops ifc_vdpa_ops ={ >>>       .get_config    = ifcvf_vdpa_get_config, >>>       .set_config    = ifcvf_vdpa_set_config, >>>       .set_config_cb  = ifcvf_vdpa_set_config_cb, >>> +    .get_vq_notification = ifcvf_get_vq_notification, >>>   }; >>>     static int ifcvf_probe(struct pci_dev *pdev, const struct >>> pci_device_id *id) >> >