ACK: [SRU][J:linux-gcp-6.8][PATCH 0/1] Disable IOMMU Passthrough by default

[Vinicius Peixoto]

On Thu Apr 16, 2026 at 9:23 PM -03, Ian Whitfield wrote:
> BugLink: https://bugs.launchpad.net/bugs/2148627
>
> [Impact]
>
> Google reported to us that some of their hardware fails to finish booting due to
> a kernel hang on 22.04 linux-gcp-6.8. This issue was traced to IOMMU passthrough
> being enabled by default, which was to originally resolve LP: #2085904. The
> root cause of that issue was fixed via a firmware update, so IOMMU passthrough
> no longer needs to be enabled by default, and this config change can now be
> reverted. On a test kernel with the change reverted, the new issue reported by
> Google is no longer reproducible.
>
> [Fix]
>
> Remove the config annotations that enable IOMMU passthrough by default.
>
> [Test Plan]
>
> To confirm that the C3-metal issue is resolved, repeat the test plan for LP:
> #2085904. Any failures indicate that IOMMU passthrough needs to remain enabled
> by default.
>
> To confirm that the new issue is resolved, verify that the specified hardware
> is able to now boot after the change is applied, without hanging during IOMMU
> initialization.
>
> [Regression potential]
>
> Regression potential is low because the annotation change is provably effective
> at changing the config, and we can confirm both of the affected instance types
> have their original problems resolved by the change.
>
> Ian Whitfield (1):
>   UBUNTU: [Config] gcp-6.8: Disable IOMMU passthrough by default
>
>  debian.gcp-6.8/config/annotations | 9 ---------
>  1 file changed, 9 deletions(-)

Acked-by: Vinicius Peixoto <vinicius.peixoto at canonical.com>