From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: Re: [PATCH v2 1/2] iommu: Quirked PCIe bridge test and search function Date: Tue, 28 May 2013 13:28:19 -0700 Message-ID: <20130528132819.2f1bc333@nehalam.linuxnetplumber.net> References: <20130528183527.3318.5365.stgit@bling.home> <20130528184020.3318.7800.stgit@bling.home> <20130528123827.2507c34e@nehalam.linuxnetplumber.net> <1369770790.2646.272.camel@ul30vt.home> <20130528125650.5ca5b419@nehalam.linuxnetplumber.net> <1369772124.2646.288.camel@ul30vt.home> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1369772124.2646.288.camel@ul30vt.home> Sender: linux-pci-owner@vger.kernel.org To: Alex Williamson Cc: iommu@lists.linux-foundation.org, dwmw2@infradead.org, joro@8bytes.org, linux-pci@vger.kernel.org, ddutile@redhat.com List-Id: iommu@lists.linux-foundation.org On Tue, 28 May 2013 14:15:24 -0600 Alex Williamson wrote: > On Tue, 2013-05-28 at 12:56 -0700, Stephen Hemminger wrote: > > On Tue, 28 May 2013 13:53:10 -0600 > > Alex Williamson wrote: > > > > > On Tue, 2013-05-28 at 12:38 -0700, Stephen Hemminger wrote: > > > > On Tue, 28 May 2013 12:40:20 -0600 > > > > Alex Williamson wrote: > > > > > > > > > Some PCIe-to-PCI bridges are not fully compliant with the PCIe spec > > > > > and do not include a PCIe capability. pci_is_pcie() is not useful on > > > > > these devices, making it difficult to determine where we transition > > > > > from a legacy PCI bus to a PCIe link. PCI-core doesn't want a quirked > > > > > bridge test for fear of confusion that a PCIe capability would be > > > > > expected, so implement it in IOMMU code. > > > > > > > > > > Signed-off-by: Alex Williamson > > > > > > > > This won't work for me because I run without IOMMU. > > > > The overhead of IOMMU setup per-packet significantly impacts network performance. > > > > > > You were one of the reporters of this issue: > > > > > > http://www.spinics.net/lists/linux-pci/msg19579.html > > > > > > Does this not work for you or are you saying this is not relevant to you > > > because you no longer attempt to enable the IOMMU? Thanks, > > > > > > > For most usage, I gave up on using IOMMU/SR-IOV. > > Ok, let's call that a "don't care" rather than "won't work" for the > purposes of these patches. I'll take you off the CC if there's another > version. Thanks, > > Alex > Yes, it is a don't care. but leave me on cc, because I may still need it.