Re: [PATCH 0/2] iommu/vt-d: Keep RMRR mappings around on driver unbind
From: Jerry Hoemann
Date: Wed Oct 01 2014 - 20:30:49 EST
On Tue, Sep 30, 2014 at 01:02:01PM +0200, Joerg Roedel wrote:
> Hi,
>
> here is a patch-set to fix an issue recently discovered when
> the Intel IOMMU is in use with devices that need RMRR
> mappings.
>
> The problem is that the RMRR mappings are destroyed when the
> device driver is unbound from the device, causing DMAR
> faults.
>
> To solve this problem a device driver core change is
> necessary to catch the right point in time for the IOMMU
> code to destroy any mappings for a device.
>
> With this patch-set the RMRR mappings are only destroyed
> when the device is actually removed from the system.
>
> Please review.
>
> Thanks,
>
> Joerg
>
> Joerg Roedel (2):
> driver core: Add BUS_NOTIFY_REMOVED_DEVICE event
> iommu/vt-d: Only remove domain when device is removed
>
> drivers/base/core.c | 3 +++
> drivers/iommu/intel-iommu.c | 11 +----------
> include/linux/device.h | 11 ++++++-----
> 3 files changed, 10 insertions(+), 15 deletions(-)
>
> --
> 1.9.1
Joerg,
I tested on HP Gen7 and Gen9 systems for which we experience dmar faults
when we rmmod a driver whose device had RMRR regions associated with it.
We don't see problem when patch set is applied.
Thanks,
Tested-by: Jerry Hoemann <jerry.hoemann@xxxxxx>
--
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Jerry Hoemann Software Engineer Hewlett-Packard
3404 E Harmony Rd. MS 36 phone: (970) 898-1022
Ft. Collins, CO 80528 FAX: (970) 898-0707
email: jerry.hoemann@xxxxxx
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