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Message-Id: <201606030228.u532PSG8045852@mx0a-001b2d01.pphosted.com>
Date: Fri, 3 Jun 2016 10:28:21 +0800
From: Yongji Xie <xyjxie@...ux.vnet.ibm.com>
To: Alex Williamson <alex.williamson@...hat.com>
Cc: kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-pci@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
iommu@...ts.linux-foundation.org, bhelgaas@...gle.com,
aik@...abs.ru, benh@...nel.crashing.org, paulus@...ba.org,
mpe@...erman.id.au, joro@...tes.org, warrier@...ux.vnet.ibm.com,
zhong@...ux.vnet.ibm.com, nikunj@...ux.vnet.ibm.com,
eric.auger@...aro.org, will.deacon@....com,
gwshan@...ux.vnet.ibm.com, alistair@...ple.id.au,
ruscur@...sell.cc, kevin.tian@...el.com, David.Laight@...LAB.COM
Subject: Re: [RESEND PATCH v2 0/6] vfio-pci: Add support for mmapping MSI-X
table
Hi, Alex
On 2016/6/2 21:11, Alex Williamson wrote:
> AFAICT, you posted this *3* days ago, has something changed here or is
> this just expedited nagging for review? This also depends on a
> non-upstream series and crosses multiple functional areas, all of which
> make it difficult for maintainers to actually do anything with this
> series. Thanks,
>
> Alex
I resend this series because I found the message-id of the previous email
is changed unexpectedly. The cover letter is not in the same thread as other
patches. It would be a little hard for people to review.
Thanks,
Yongji
> On Thu, 2 Jun 2016 14:09:57 +0800
> Yongji Xie <xyjxie@...ux.vnet.ibm.com> wrote:
>
>> 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 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
>>
>> Yongji Xie (6):
>> PCI: Add a new PCI_BUS_FLAGS_MSI_REMAP flag
>> PCI: Set PCI_BUS_FLAGS_MSI_REMAP if MSI controller enables IRQ remapping
>> PCI: Set PCI_BUS_FLAGS_MSI_REMAP if IOMMU have capability of IRQ remapping
>> iommu: Set PCI_BUS_FLAGS_MSI_REMAP on iommu driver initialization
>> 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
>>
>> arch/powerpc/platforms/powernv/pci-ioda.c | 8 ++++++++
>> drivers/iommu/iommu.c | 8 ++++++++
>> drivers/pci/msi.c | 15 +++++++++++++++
>> drivers/pci/probe.c | 7 +++++++
>> drivers/vfio/pci/vfio_pci.c | 17 ++++++++++++++---
>> drivers/vfio/pci/vfio_pci_rdwr.c | 3 ++-
>> include/linux/msi.h | 5 ++++-
>> include/linux/pci.h | 1 +
>> 8 files changed, 59 insertions(+), 5 deletions(-)
>>
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