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| /openbmc/linux/drivers/iommu/amd/ |
| H A D | init.c | diff 9b45a7738eec52bf0f5d8d3d54e822962781c5f2 Fri Feb 04 05:55:37 CST 2022 Joerg Roedel <jroedel@suse.de> iommu/amd: Fix loop timeout issue in iommu_ga_log_enable()
The polling loop for the register change in iommu_ga_log_enable() needs
to have a udelay() in it. Otherwise the CPU might be faster than the
IOMMU hardware and wrongly trigger the WARN_ON() further down the code
stream. Use a 10us for udelay(), has there is some hardware where
activation of the GA log can take more than a 100ms.
A future optimization should move the activation check of the GA log
to the point where it gets used for the first time. But that is a
bigger change and not suitable for a fix.
Fixes: 8bda0cfbdc1a ("iommu/amd: Detect and initialize guest vAPIC log")
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Link: https://lore.kernel.org/r/20220204115537.3894-1-joro@8bytes.org
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