group.of.nepali.translators team mailing list archive

[Andrea Righi <1913739@xxxxxxxxxxxxxxxxxx>]

** Description changed:

  [Impact]
  
  To properly support instance types in AWS with > 255 cores we need to
  make sure that commit c40aaaac1018ff1382f2d35df5129a6bcea3df6b
  ("iommu/vt-d: Gracefully handle DMAR units with no supported address
  widths") is applied across all our linux-aws kernels.
  
  [Test Case]
  
  Tests performed by AWS.
  
  [Fix]
  
  Apply/backport commit c40aaaac1018ff1382f2d35df5129a6bcea3df6b.
  
+ For groovy it's a clean cherry pick.
+ 
+ For Focal/Bionic the backport activity is to simply rename the patched
+ file.
+ 
+ Only Xenial requires a little more backporting activity, in particular
+ we need to change the condition in free_iommu() checking if
+ iommu->iommu_dev is defined (instead of checking for iommu->iommu.ops,
+ that is not available in the 4.4 kernel).
+ 
  [Regression potential]
  
- The fix is affecting only intel IOMMU and it is an upstream fix, so the
- regression potential is minimal.
+ This change allows to use DMAR units that were not used before (for
+ interrupt remapping). Theoretically this should provide a performance
+ improvement, but we should keep an eye about potential performance
+ regressions of drivers that are using IOMMU, in case they're using this
+ new behavior incorrectly.
+ 
+ Moreover, the Xenial backport required an adjustment in free_iommu() to
+ check when we need to call iommu_device_destroy(), if the adjustment is
+ not 100% correct we could introduce a potential memory leak.

** No longer affects: linux-aws (Ubuntu Hirsute)

-- 
You received this bug notification because you are a member of नेपाली
भाषा समायोजकहरुको समूह, which is subscribed to Xenial.
Matching subscriptions: Ubuntu 16.04 Bugs
https://bugs.launchpad.net/bugs/1913739

Title:
  aws: properly support instance types with > 255 cpu cores

Status in linux-aws package in Ubuntu:
  New
Status in linux-aws source package in Xenial:
  In Progress
Status in linux-aws source package in Bionic:
  In Progress
Status in linux-aws source package in Focal:
  In Progress
Status in linux-aws source package in Groovy:
  In Progress

Bug description:
  [Impact]

  To properly support instance types in AWS with > 255 cores we need to
  make sure that commit c40aaaac1018ff1382f2d35df5129a6bcea3df6b
  ("iommu/vt-d: Gracefully handle DMAR units with no supported address
  widths") is applied across all our linux-aws kernels.

  [Test Case]

  Tests performed by AWS.

  [Fix]

  Apply/backport commit c40aaaac1018ff1382f2d35df5129a6bcea3df6b.

  For groovy it's a clean cherry pick.

  For Focal/Bionic the backport activity is to simply rename the patched
  file.

  Only Xenial requires a little more backporting activity, in particular
  we need to change the condition in free_iommu() checking if
  iommu->iommu_dev is defined (instead of checking for iommu->iommu.ops,
  that is not available in the 4.4 kernel).

  [Regression potential]

  This change allows to use DMAR units that were not used before (for
  interrupt remapping). Theoretically this should provide a performance
  improvement, but we should keep an eye about potential performance
  regressions of drivers that are using IOMMU, in case they're using
  this new behavior incorrectly.

  Moreover, the Xenial backport required an adjustment in free_iommu()
  to check when we need to call iommu_device_destroy(), if the
  adjustment is not 100% correct we could introduce a potential memory
  leak.

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux-aws/+bug/1913739/+subscriptions