[Bug 218257] [Nested VM] Failed to boot L2 Windows guest on L1 Windows guest

bugzilla-daemon
2023-12-13T17:00:26Z

--- Comment #1 from Sean Christopherson (seanjc@google.com) ---
On Tue, Dec 12, 2023, bugzilla-daemon@kernel.org wrote:
> Environment:
> ------------
> CPU Architecture: x86_64
> Host OS: CentOS Stream 9
> Guest OS L1: Windows 10 Pro (10.0.18362 N/A Build 18362), x64-based PC
> Guest OS L2: Windows 10 Enterprises (10.0.10240 N/A Build 10240), x64-based
> PC
> kvm.git next branch commit id: e9e60c82fe391d04db55a91c733df4a017c28b2f
> qemu-kvm commit id:
> Host Kernel Version: 6.7.0-rc1
> Hardware: Sapphire Rapids
>
> Bug detailed description:
> --------------------------
> To verify two nested Windows guests scenarios, we used Windows image to
> create
> L1 guest, then failed to boot L2 Windows guest on L1 guest. The error screen
> is
> captured in attachment.
>
> Note: this is suspected to be a KVM Kernel bug by bisect the different
> commits:
> kvm next + qemu-kvm = result
> a1c288f87de7aff94e87724127eabb6cdb38b120 + d451e32c = bad
> e1a6d5cf10dd93fc27d8c85cd7b3e41f08a816e6 + d451e32c = good

Assuming `git bisect` didn't point at exactly the merge commit, can you please
bisect to the exact commit, instead of the merge commit? I.e.

git bisect start
git bisect bad a1c288f87de7aff94e87724127eabb6cdb38b120
git bisect good e1a6d5cf10dd93fc27d8c85cd7b3e41f08a816e6

and go from there.

Hopefully it isn't the merge commit that's being blamed, as that will be far
more
painful to figure out.