Re: [PATCH 2/3] iommu/amd: Add IOMMU event log injection interfacefor testing event flag decoding logic

From: Joerg Roedel
Date: Tue Apr 02 2013 - 10:35:32 EST


On Wed, Mar 27, 2013 at 06:51:34PM -0500, suravee.suthikulpanit@xxxxxxx wrote:
> From: Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx>
>
> Add IOMMU event log injection interface for testing event flag decoding logic.
> This interface allows users to specify device id, event flag, and event types via debugfs.
>
> echo 0x300 > /sys/kernel/debug/amd-iommu-evninj/devid // (e.g. Bus:Dev.fun 3:0.0)
> echo 0xfff > /sys/kernel/debug/amd-iommu-evninj/flags // (e.g. Specify flag value)
> echo 2 > /sys/kernel/debug/amd-iommu-evninj/type // (e.g. for IO_PAGE_FAULT event)
>
> Once the event is injected, IOMMU driver will parse and print out the event information
> in kernel log (dmesg) with the various information depending on the types of event and flag
> specified.

Why is this needed? I think the risk of regressions in the
event-handling code is to low to justify the need for an event-injection
mechanism.

Joerg


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