Ubuntu
linux-aws package

  1. Xenial (16.04)
  2. Bug #1668129
  3. Comment #50

Comment 50 for bug 1668129

Revision history for this message
Dan Streetman (ddstreet) wrote :

> Is there any intention of backporting either linux-aws or any of the NVMe bug fixes from
> linux-aws into linux-image-virtual-lts-xenial for Ubuntu 14.04 since they're both
> 4.4.0 kernels?

the fix for this bug is to change the kernel config param CONFIG_XEN_BALLOON from y to n, disabling Xen ballooning in the linux-aws kernel. This avoids the problems associated with DMA to/from the memory pages added by the balloon driver, which are physically located outside the e820 region.

As such, there is no actual code change to backport into the generic xenial (or other release) kernel, and disabling Xen ballooning in the generic kernel is inappropriate, as it would remove functionality from any other Ubuntu-under-Xen users who do want to use Xen ballooning.

An upstream discussion on this particular issue is here:
https://lkml.org/lkml/2017/3/22/878

we're consulting Amazon to see if they may be able to update the AWS hypervisor to reject any requests by the linux guest to register hotadded memory pages, which would also fix this problem.