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

From: Don Dutile
Date: Tue Dec 10 2013 - 12:04:11 EST


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 ?


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