Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751888AbdFOFoP (ORCPT ); Thu, 15 Jun 2017 01:44:15 -0400 Received: from mail-it0-f65.google.com ([209.85.214.65]:36139 "EHLO mail-it0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750783AbdFOFoM (ORCPT ); Thu, 15 Jun 2017 01:44:12 -0400 Subject: Re: [PATCH kernel 0/3] vfio-pci: Add support for mmapping MSI-X table To: linuxppc-dev@lists.ozlabs.org Cc: kvm@vger.kernel.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, Yongji Xie , Alex Williamson , Benjamin Herrenschmidt , Gavin Shan , Paul Mackerras , David Gibson References: <20170615050642.8197-1-aik@ozlabs.ru> From: Alexey Kardashevskiy Message-ID: Date: Thu, 15 Jun 2017 15:44:04 +1000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.1.0 MIME-Version: 1.0 In-Reply-To: <20170615050642.8197-1-aik@ozlabs.ru> Content-Type: text/plain; charset=koi8-r Content-Language: en-AU Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2390 Lines: 68 Ouch, this is a wrong one, please ignore. I'll repost in a sec. On 15/06/17 15:06, Alexey Kardashevskiy wrote: > Here is a patchset which Yongji was working on before > leaving IBM LTC. Since we still want to have this functionality > in the kernel (DPDK is the first user), here is a rebase > on the current upstream. > > > Current vfio-pci implementation disallows to mmap the page > containing MSI-X table in case that users can write directly > to MSI-X table and generate an incorrect MSIs. > > However, this will cause some performance issue when there > are some critical device registers in the same page as the > MSI-X table. We have to handle the mmio access to these > registers in QEMU emulation rather than in guest. > > To solve this issue, this series allows to expose MSI-X table > to userspace when hardware enables the capability of interrupt > remapping which can ensure that a given PCI device can only > shoot the MSIs assigned for it. And we introduce a new bus_flags > PCI_BUS_FLAGS_MSI_REMAP to test this capability on PCI side > for different archs. > > The patch 3 are based on the proposed patchset[1]. > > Changelog > v3: > - rebased on the current upstream > > v2: > - Make the commit log more clear > - Replace pci_bus_check_msi_remapping() with pci_bus_msi_isolated() > so that we could clearly know what the function does > - Set PCI_BUS_FLAGS_MSI_REMAP in pci_create_root_bus() instead > of iommu_bus_notifier() > - Reserve VFIO_REGION_INFO_FLAG_CAPS when we allow to mmap MSI-X > table so that we can know whether we allow to mmap MSI-X table > in QEMU > > [1] https://www.mail-archive.com/linux-kernel%40vger.kernel.org/msg1138820.html > > > This is based on sha1 > 63f700aab4c1 Linus Torvalds "Merge tag 'xtensa-20170612' of git://github.com/jcmvbkbc/linux-xtensa". > > Please comment. Thanks. > > > > Yongji Xie (3): > PCI: Add a new PCI_BUS_FLAGS_MSI_REMAP flag > pci-ioda: Set PCI_BUS_FLAGS_MSI_REMAP for IODA host bridge > vfio-pci: Allow to expose MSI-X table to userspace if interrupt > remapping is enabled > > include/linux/pci.h | 1 + > arch/powerpc/platforms/powernv/pci-ioda.c | 8 ++++++++ > drivers/vfio/pci/vfio_pci.c | 18 +++++++++++++++--- > drivers/vfio/pci/vfio_pci_rdwr.c | 3 ++- > 4 files changed, 26 insertions(+), 4 deletions(-) > -- Alexey