Received: by 2002:ac0:a5b6:0:0:0:0:0 with SMTP id m51-v6csp1746270imm;
        Thu, 14 Jun 2018 03:13:58 -0700 (PDT)
X-Google-Smtp-Source: ADUXVKIK1VaqGOD7b25GQLuNnIfKl4m7ShZInKh1UNuJ86ZhQ/G/FvIn/VRgcARSsZHaDZR4pf3e
X-Received: by 2002:a62:9e0b:: with SMTP id s11-v6mr8848188pfd.198.1528971238223;
        Thu, 14 Jun 2018 03:13:58 -0700 (PDT)
ARC-Seal: i=1; a=rsa-sha256; t=1528971238; cv=none;
        d=google.com; s=arc-20160816;
        b=X+2ho13QleKEEu9A1Gv+QwMIMMDnRVjqY/M2O9ef5ZQxxFLhVJwY7gaNV52FzygZQw
         IP08MWqem+UMBFN3aCGmZl8TGIpG56bhtw2L+nG3NMhYk7Tt+7XHcUDdRF92ijxqDAWA
         39Nk9S/gBEDreTcw9YkfoSfc6vQzPIZ33C7++9EIoz7DZ3dm7b0XPD9qPx3lca8LMdTf
         IaZEyndpIn4ERlPxTCS2eo84OD3CmXnbG4NZm7pVywWu1jLOaqmaEd1Dj3fV+oZKGf+s
         242yZytenomhS2b335GwEadMxMhRFVQS8USBb9SOGHHgWXMgk8ksFrcqZhI8d2s6KlL0
         jhFw==
ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816;
        h=list-id:precedence:sender:user-agent:in-reply-to
         :content-disposition:mime-version:references:message-id:subject:cc
         :to:from:date:arc-authentication-results;
        bh=1bgkeiUd847oViEUag7nuD2WXLuqe6ZtKIXG5LbcU/k=;
        b=O920K3tINtoZczHUAzFrB3XXM5pn6EFdplUQzOOb45H2m7DWZROvAuvEsND3jhL/Sm
         D3Voo5JljwKuhnaMfDnOCtRzfNJGyqd9q61fWyFkCst34kzBcS041xfrWYfrPahFpuFP
         mwmpiBSqxi+75auBYyjNf/pUrzntOwb2qKTkqIen5X38vqYjP7iqJZpzZewrZR5iW3gC
         uETUddbgRTFlz3tvLEAdWQ8sB9vcI2do7fu/NnET7r6EU6w6SnhjawVInY3rbPqQasCB
         PkwnXHgfOxJQF+qvlYcjt00b/d22RusO6UDp/nPVtDE8rK/REMaUOUdesYBUtEzSVDVG
         egkg==
ARC-Authentication-Results: i=1; mx.google.com;
       spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67])
        by mx.google.com with ESMTP id v66-v6si4177368pgv.57.2018.06.14.03.13.43;
        Thu, 14 Jun 2018 03:13:58 -0700 (PDT)
Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Authentication-Results: mx.google.com;
       spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1755008AbeFNKLn (ORCPT <rfc822;yingkeliu@gmail.com> + 99 others);
        Thu, 14 Jun 2018 06:11:43 -0400
Received: from verein.lst.de ([213.95.11.211]:45550 "EHLO newverein.lst.de"
        rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
        id S1754794AbeFNKLm (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
        Thu, 14 Jun 2018 06:11:42 -0400
Received: by newverein.lst.de (Postfix, from userid 2407)
        id B2C9468C4E; Thu, 14 Jun 2018 12:20:01 +0200 (CEST)
Date:   Thu, 14 Jun 2018 12:20:01 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     Srinath Mannam <srinath.mannam@broadcom.com>
Cc:     Bjorn Helgaas <bhelgaas@google.com>,
        Christoph Hellwig <hch@lst.de>,
        Abhishek Shah <abhishek.shah@broadcom.com>,
        Vikram Prakash <vikram.prakash@broadcom.com>,
        linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-nvme@lists.infradead.org
Subject: Re: Requirement to get BAR pci_bus_address in user space
Message-ID: <20180614102001.GA20836@lst.de>
References: <CABe79T41Cr0mjH_k2drzccHvObFwRcW3n+WKCj0JvFUBy0wz-A@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <CABe79T41Cr0mjH_k2drzccHvObFwRcW3n+WKCj0JvFUBy0wz-A@mail.gmail.com>
User-Agent: Mutt/1.5.17 (2007-11-01)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

The only safe way to use PCI(e) devices in userspace is through vfio.
I think that is where you need to take your inquiries.