From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by dpdk.org (Postfix) with ESMTP id 6C8A256B7 for ; Tue, 29 Sep 2015 23:49:23 +0200 (CEST) Received: from int-mx14.intmail.prod.int.phx2.redhat.com (int-mx14.intmail.prod.int.phx2.redhat.com [10.5.11.27]) by mx1.redhat.com (Postfix) with ESMTPS id B67C871; Tue, 29 Sep 2015 21:49:22 +0000 (UTC) Received: from redhat.com (ovpn-116-28.ams2.redhat.com [10.36.116.28]) by int-mx14.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with SMTP id t8TLnJ3H006584; Tue, 29 Sep 2015 17:49:20 -0400 Date: Wed, 30 Sep 2015 00:49:18 +0300 From: "Michael S. Tsirkin" To: Stephen Hemminger Message-ID: <20150930004714-mutt-send-email-mst@redhat.com> References: <56079527.3000802@cloudius-systems.com> <20150927123914-mutt-send-email-mst@redhat.com> <560ABF25.9030300@cloudius-systems.com> <20150929235122-mutt-send-email-mst@redhat.com> <20150929144616.4e70b44c@urahara> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150929144616.4e70b44c@urahara> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.27 Cc: "dev@dpdk.org" Subject: Re: [dpdk-dev] Having troubles binding an SR-IOV VF to uio_pci_generic on Amazon instance X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 29 Sep 2015 21:49:23 -0000 On Tue, Sep 29, 2015 at 02:46:16PM -0700, Stephen Hemminger wrote: > On Tue, 29 Sep 2015 23:54:54 +0300 > "Michael S. Tsirkin" wrote: > > > On Tue, Sep 29, 2015 at 07:41:09PM +0300, Vlad Zolotarov wrote: > > > The security breach motivation u brought in "[RFC PATCH] uio: > > > uio_pci_generic: Add support for MSI interrupts" thread seems a bit weak > > > since one u let the userland access to the bar it may do any funny thing > > > using the DMA engine of the device. This kind of stuff should be prevented > > > using the iommu and if it's enabled then any funny tricks using MSI/MSI-X > > > configuration will be prevented too. > > > > > > I'm about to send the patch to main Linux mailing list. Let's continue this > > > discussion there. > > > > > > > Basically UIO shouldn't be used with devices capable of DMA. > > Use VFIO for that (yes, this implies an emulated or PV IOMMU). > > I don't think this can change. > > Given there is no PV IOMMU and even if there was it would be too slow for DPDK > use, I can't accept that. QEMU does allow emulating an iommu. DPDK uses static mappings, so I doubt it's speed matters at all. Anyway, DPDK is doing polling all the time. I don't see why does it insist on using interrupts to detect link up events. Just poll for that too. -- MST