Re: [PATCH] iommu/amd: Add workaround to propery clearing IOMMU statusregister
From: Suravee Suthikulanit
Date: Tue Apr 09 2013 - 10:23:12 EST
On 4/9/2013 4:49 AM, Joerg Roedel wrote:
On Wed, Apr 03, 2013 at 06:19:04PM -0500, Suthikulpanit, Suravee wrote:
In the system with multiple IOMMU,this handling scheme complicates the
synchronization of the IOMMU data structures and status registers as
there could be multiple threads competing for the same IOMMU while
the other IOMMU could be left unhandled.
I really like that change in the interrupt handling code to pull the
different IOMMUs independently. But its problematic to change that in
the same patch that adds an erratum workaround.
Please move that erratum fix into a seperate small patch that we can
backport to -stable and resend.
Joerg
Joerg,
The reason I implemented the "per-thread IOMMU handling" and the
"workaround" together in one patch
is because it simplifies the synchronization of clearing and checking
the interrupt enabling bits.
In the previous implementation, we could end up having multiple threads
trying to access the status register
at the same time.
Suravee
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