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=-15.8 required=3.0 tests=BAYES_00, 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 16304C47080 for ; Tue, 1 Jun 2021 03:27:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EA30C6135C for ; Tue, 1 Jun 2021 03:27:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232787AbhFAD32 (ORCPT ); Mon, 31 May 2021 23:29:28 -0400 Received: from mga14.intel.com ([192.55.52.115]:18754 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232515AbhFAD32 (ORCPT ); Mon, 31 May 2021 23:29:28 -0400 IronPort-SDR: 8Y6gkBWA4n93WbURa/Zi+boRI4v3M01Qx2liCxryoOzseSCfKesVQ3VX15fXp33JQ5VRuHNKbr M8kYxAbm2dcw== X-IronPort-AV: E=McAfee;i="6200,9189,10001"; a="203267176" X-IronPort-AV: E=Sophos;i="5.83,239,1616482800"; d="scan'208";a="203267176" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 31 May 2021 20:27:47 -0700 IronPort-SDR: Ut/19svZPkIiIO53f0VSY49q/qX06epLglQU70tOb4zT+Q93Y2nwsAQhDnoA9bQ+x7vFOb5nds hUzCGZgjI7hA== X-IronPort-AV: E=Sophos;i="5.83,239,1616482800"; d="scan'208";a="445169944" Received: from lingshan-mobl5.ccr.corp.intel.com (HELO [10.254.215.13]) ([10.254.215.13]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 31 May 2021 20:27:45 -0700 Subject: Re: [PATCH V2 RESEND 2/2] vDPA/ifcvf: implement doorbell mapping for ifcvf To: Jason Wang , mst@redhat.com Cc: virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, kvm@vger.kernel.org References: <20210531073316.363655-1-lingshan.zhu@intel.com> <20210531073316.363655-3-lingshan.zhu@intel.com> From: "Zhu, Lingshan" Message-ID: <5dbdc6a5-1510-9411-6b85-d947d091089c@intel.com> Date: Tue, 1 Jun 2021 11:27:43 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On 5/31/2021 3:56 PM, Jason Wang wrote: > > 在 2021/5/31 下午3:33, 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 | 17 +++++++++++++++++ >>   1 file changed, 17 insertions(+) >> >> diff --git a/drivers/vdpa/ifcvf/ifcvf_main.c >> b/drivers/vdpa/ifcvf/ifcvf_main.c >> index ab0ab5cf0f6e..effb0e549135 100644 >> --- a/drivers/vdpa/ifcvf/ifcvf_main.c >> +++ b/drivers/vdpa/ifcvf/ifcvf_main.c >> @@ -413,6 +413,22 @@ 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_adapter *adapter = vdpa_to_adapter(vdpa_dev); >> +    struct ifcvf_hw *vf = vdpa_to_vf(vdpa_dev); >> +    struct pci_dev *pdev = adapter->pdev; >> +    struct vdpa_notification_area area; >> + >> +    area.addr = vf->vring[idx].notify_pa; >> +    area.size = PAGE_SIZE; >> +    if (area.addr % PAGE_SIZE) >> +        IFCVF_DBG(pdev, "vq %u doorbell address is not PAGE_SIZE >> aligned\n", idx); > > > Let's leave the decision to upper layer by: (see > vp_vdpa_get_vq_notification) > > area.addr = notify_pa; > area.size = notify_offset_multiplier; > > Thanks Hi Jason, notify_offset_multiplier can be zero, means vqs share the same doorbell address, distinguished by qid. and in vdpa.c:         if (vma->vm_end - vma->vm_start != notify.size)                 return -ENOTSUPP; so a zero size would cause this feature failure. mmap should work on at least a page, so if we really want "area.size = notify_offset_multiplier;" I think we should add some code in vdpa.c, like: if(!notify.size)     notify.size = PAGE_SIZE; sounds good? Thanks Zhu Lingshan > > >> + >> +    return area; >> +} >> + >>   /* >>    * IFCVF currently does't have on-chip IOMMU, so not >>    * implemented set_map()/dma_map()/dma_unmap() >> @@ -440,6 +456,7 @@ 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) >