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=ham 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 3543DC433E0 for ; Thu, 11 Mar 2021 06:14:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F2C5C64FCE for ; Thu, 11 Mar 2021 06:14:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229972AbhCKGOG (ORCPT ); Thu, 11 Mar 2021 01:14:06 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:25604 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229932AbhCKGNe (ORCPT ); Thu, 11 Mar 2021 01:13:34 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1615443213; 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=O9dIFx5T4B5wQEwSmY/A6qMcWPDW41QAG6OtpF0Rp64=; b=OEmBVMboLLBGPCjTcsuRU8tLDXe7ddsx8bVFxx2P44JFlprfDmyfuA/3mru/NiXyOHTQrD znFDsbtZgyUnkG9kKxXcSR6P5jarNav05VnCtCZVcw5vgqBLY2kubf8sXWfeIdDSmm9jX+ jBmrKRZM3Sm/QB7vLQTYoorLjCWUmg8= 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-585-WCvA8jlCO1WyXxzT1CSOpQ-1; Thu, 11 Mar 2021 01:13:29 -0500 X-MC-Unique: WCvA8jlCO1WyXxzT1CSOpQ-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 345071858F17; Thu, 11 Mar 2021 06:13:28 +0000 (UTC) Received: from wangxiaodeMacBook-Air.local (ovpn-13-9.pek2.redhat.com [10.72.13.9]) by smtp.corp.redhat.com (Postfix) with ESMTP id 2D63A5945D; Thu, 11 Mar 2021 06:13:21 +0000 (UTC) Subject: Re: [PATCH V3 1/6] vDPA/ifcvf: get_vendor_id returns a device specific vendor id To: Zhu Lingshan , Zhu Lingshan , mst@redhat.com, lulu@redhat.com, leonro@nvidia.com Cc: virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org References: <20210310090052.4762-1-lingshan.zhu@intel.com> <20210310090052.4762-2-lingshan.zhu@intel.com> <5f2d915f-e1b0-c9eb-9fc8-4b64f5d8cd0f@linux.intel.com> From: Jason Wang Message-ID: <05e3fbc9-be49-a208-19a4-85f891323312@redhat.com> Date: Thu, 11 Mar 2021 14:13:20 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.16; rv:78.0) Gecko/20100101 Thunderbird/78.8.0 MIME-Version: 1.0 In-Reply-To: <5f2d915f-e1b0-c9eb-9fc8-4b64f5d8cd0f@linux.intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-GB X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 2021/3/11 12:21 下午, Zhu Lingshan wrote: > > > On 3/11/2021 11:23 AM, Jason Wang wrote: >> >> On 2021/3/10 5:00 下午, Zhu Lingshan wrote: >>> In this commit, ifcvf_get_vendor_id() will return >>> a device specific vendor id of the probed pci device >>> than a hard code. >>> >>> Signed-off-by: Zhu Lingshan >>> --- >>>   drivers/vdpa/ifcvf/ifcvf_main.c | 5 ++++- >>>   1 file changed, 4 insertions(+), 1 deletion(-) >>> >>> diff --git a/drivers/vdpa/ifcvf/ifcvf_main.c >>> b/drivers/vdpa/ifcvf/ifcvf_main.c >>> index fa1af301cf55..e501ee07de17 100644 >>> --- a/drivers/vdpa/ifcvf/ifcvf_main.c >>> +++ b/drivers/vdpa/ifcvf/ifcvf_main.c >>> @@ -324,7 +324,10 @@ static u32 ifcvf_vdpa_get_device_id(struct >>> vdpa_device *vdpa_dev) >>>     static u32 ifcvf_vdpa_get_vendor_id(struct vdpa_device *vdpa_dev) >>>   { >>> -    return IFCVF_SUBSYS_VENDOR_ID; >>> +    struct ifcvf_adapter *adapter = vdpa_to_adapter(vdpa_dev); >>> +    struct pci_dev *pdev = adapter->pdev; >>> + >>> +    return pdev->subsystem_vendor; >>>   } >> >> >> While at this, I wonder if we can do something similar in >> get_device_id() if it could be simple deduced from some simple math >> from the pci device id? >> >> Thanks > Hi Jason, > > IMHO, this implementation is just some memory read ops, I think other > implementations may not save many cpu cycles, an if cost at least > three cpu cycles. > > Thanks! Well, I meant whehter you can deduce virtio device id from pdev->subsystem_device. Thanks >> >> >>>     static u32 ifcvf_vdpa_get_vq_align(struct vdpa_device *vdpa_dev) >> >