Re: [PATCH 0/2] iommu/dmar: expose fault counters via sysfs

From: Lu Baolu
Date: Tue Oct 15 2019 - 20:48:23 EST


On 10/15/19 11:11 PM, Yuri Volchkov wrote:
For health monitoring, it can be useful to know if iommu is behaving as
expected. DMAR faults can be an indicator that a device:
- has been misconfigured, or
- has experienced a hardware hiccup and replacement should
be considered, or
- has been issuing faults due to malicious activity

Currently the only way to check if there were any DMAR faults on the
host is to scan the dmesg output. However this approach is not very
elegant. The information we are looking for can be wrapped out of the
buffer, or masked (since it is a rate-limited print) by another

The series adds counters for DMAR faults and exposes them via sysfs.

We now have an iommu API named iommu_register_fault_handler() to
register callbacks for dmar faults. How about monitoring the dmar
fault through this api so that your code could be generic and vendor

Best regards,

Yuri Volchkov (2):
iommu/dmar: collect fault statistics
iommu/dmar: catch early fault occurrences

drivers/iommu/dmar.c | 182 ++++++++++++++++++++++++++++++++----
drivers/iommu/intel-iommu.c | 1 +
drivers/pci/pci-sysfs.c | 20 ++++
include/linux/intel-iommu.h | 4 +
include/linux/pci.h | 11 +++
5 files changed, 201 insertions(+), 17 deletions(-)