From mboxrd@z Thu Jan  1 00:00:00 1970
From: Don Dutile <ddutile-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Subject: Re: [PATCH v2] Enhance dmar to support device hotplug
Date: Tue, 10 Dec 2013 12:03:25 -0500
Message-ID: <52A7495D.6010905@redhat.com>
References: <1385022116-228-1-git-send-email-wangyijing@huawei.com>
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To: Yijing Wang <wangyijing-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
Cc: Vinod Koul <vinod.koul-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, dmaengine-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Hanjun Guo <guohanjun-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>, Bjorn Helgaas <bhelgaas-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>, Dan Williams <dan.j.williams-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>, David Woodhouse <dwmw2-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
List-Id: iommu@lists.linux-foundation.org

On 11/21/2013 03:21 AM, Yijing Wang wrote:
> This is the v2 patch, the v1 link: http://marc.info/?l=linux-pci&m=138364004628824&w=2
>
> v1->v2: keep (pci_dev *) pointer array in dmar_drhd_uni, only use pci device id
> 		to update pci_dev * pointer info during device hotplug in intel iommu
> 		driver notifier.
>
> Currently, DMAR driver save target pci devices pointers for drhd/rmrr/atsr
> in (pci_dev *) array, but never update these info after initialization.
> It's not safe, because pci devices maybe hot added or removed during
> system running. They will have new pci_dev * pointer. So if there have
> two IOMMUs or more in system, these devices will find a wrong drhd during
> DMA mapping. And DMAR faults will occur. This patch save pci device id
> as well as (pci_dev *) to fix this issue. Pci device id will be used to update
> pci_dev * poninter during device hotplug in intel iommu driver notifier.
> Other, here use list to manage target devices for IOMMU,
> we can easily use list helper.
>
> Yijing Wang (1):
>    IOMMU: enhance dmar to support device hotplug
>
>   drivers/iommu/dmar.c        |   82 +++++++++++-----------
>   drivers/iommu/intel-iommu.c |  161 +++++++++++++++++++++++++++++-------------
>   include/linux/dmar.h        |   24 ++++--
>   3 files changed, 167 insertions(+), 100 deletions(-)
>
>
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>

Can this bug & fix be demonstrated by configuring & de-configuring VFs
on an SRIOV device, since that effectively looks like a hot-add & hot-remove ?