Re: [PATCH v2] Enhance dmar to support device hotplug

[Don Dutile <ddutile-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.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 ?