Upstream resolution: https://lore.kernel.org/linux-
pci/[email protected]/

TL;dr "If that's the case we can go ahead and merge this patch with a
reworded commit log [...]  Clint, please reword the commit and resend,
not sure we can hit v5.10 but we shall try."

** Description changed:

- To improve PCI performance on arm64 AWS instances, enable
+ To improve PCI performance on certain arm64 AWS instance types, enable
  arch_can_pci_mmap_wc() via the patch:
  
-     From: Clint Sbisa <[email protected]>
-     Subject: [PATCH] arm64: Enable PCI write-combine resources under sysfs
+     From: Clint Sbisa <[email protected]>
+     Subject: [PATCH] arm64: Enable PCI write-combine resources under sysfs
  
-     https://lore.kernel.org/linux-
+     https://lore.kernel.org/linux-
  pci/[email protected]/
+ 
+ --------------
+ 
+ [Impact]
+ 
+  * AWS requires PCI-write-combine be enabled for arm64 via this one-line
+ patch, to effect a significant performance improvement on certain AWS
+ arm64 instance types.
+ 
+  * After considerable discussion, upstream indicates that this patch
+ will be accepted into mainline[0] once additional documentation details
+ get added to the commit description.
+ 
+  * Applying this patch to linux-aws affects only AWS arm64 instance
+ types.
+ 
+ [Test Case]
+ 
+  * Has been performance-tested by AWS; smoke-tested by me.
+ 
+ [Regression Potential]
+ 
+  * Low.
+ 
+ [0] https://lore.kernel.org/linux-
+ pci/[email protected]/

** Changed in: linux-aws (Ubuntu)
   Importance: Medium => High

** Changed in: linux-aws (Ubuntu Bionic)
   Importance: Medium => High

** Changed in: linux-aws (Ubuntu Groovy)
   Importance: Medium => High

** Changed in: linux-aws (Ubuntu Focal)
   Importance: Medium => High

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https://bugs.launchpad.net/bugs/1893817

Title:
  aws: enable PCI write-combine for arm64

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