[ARM platform]Remote snapshotter test failed on pulling image due to microVM time out of sync

[fangn2]

On ARM64 platform, remote snapshotter test failed on pulling image due to microVM time out of sync.
Failed CI build link.
When CI tried to run test TestSnapshotterMetrics_Isolated which will pull an image and unpack in remote snapshotter, it failed with below issue on pulling image(the image pulling fine on ARM host with ctr).

=== RUN   TestSnapshotterMetrics_Isolated
    metrics_integ_test.go:54:
        	Error Trace:	metrics_integ_test.go:54
        	Error:      	Received unexpected error:
        	            	Failed to pull image on microVM[0]: failed to extract layer sha256:fdb3c0ecba2ee0b2b39f778f7da3beb4ee4c75f6f4b8a083211b12971fde4ad6: failed to mount /var/lib/containerd/tmpmounts/containerd-mount3440161598: no such file or directory: unknown
        	Test:       	TestSnapshotterMetrics_Isolated

Checked the containerd.log for the test, found that there is Error x509: certificate has expired or is not yet valid: current time 2022-08-07T13:25:13Z is before 2023-02-21T00:00:00Z seems the microVM time is not synced right.

{\"key\":\"0/1/extract-101125884-ByGC sha256:fdb3c0ecba2ee0b2b39f778f7da3beb4ee4c75f6f4b8a083211b12971fde4ad6\",\"level\":\"info\",\"mountpoint\":\"/var/lib/containerd-stargz-grpc/snapshotter/snapshots/1/fs\",\"msg\":\"Received status code: 401 Unauthorized. Refreshing creds...\",\"parent\":\"\",\"src\":\"ghcr.io/firecracker-microvm/firecracker-containerd/amazonlinux:latest-esgz/sha256:efc8b66d208d6eaa2e24799081e13c035f25ad585cec5d478845a744f98324b8\",\"time\":\"2022-08-07T13:25:13.491954298Z\"}" jailer=noop runtime=aws.firecracker vmID=0 vmm_stream=stdout
time="2023-04-06T18:05:06.129064764Z" level=debug msg="[    5.441207] containerd-stargz-grpc[744]: {\"error\":\"Get \\\"https://pkg-containers.githubusercontent.com/ghcr1/blobs/sha256:efc8b66d208d6eaa2e24799081e13c035f25ad585cec5d478845a744f98324b8?se=2023-04-06T18%3A15%3A00Z\\u0026sig=8ccbSSbYFbIlb%2Fr9eh5ptZlKm5W1pkw50WfKqVLTY4A%3D\\u0026sp=r\\u0026spr=https\\u0026sr=b\\u0026sv=2019-12-12\\\": x509: certificate has expired or is not yet valid: current time 2022-08-07T13:25:13Z is before 2023-02-21T00:00:00Z\"

Tried to set the microVM time in the commit, but didn’t make effect, rerun still had old time.
Strange part is AMD platform build has the right time in MicroVM.

[BinSquare]

Guest kernels needs to be compiled with KVM_PTP support as a mechanism for clock sync.

CONFIG_PTP_1588_CLOCK=y
CONFIG_PTP_1588_CLOCK_KVM=y

We can see that all the arm microvm kernel configs are missing CONFIG_PTP_1588_CLOCK_KVM=y incomparison to all the x86 configs. This discrepancy is due to 4.14 arm64 missing the feature which has been upstreamed since 5.3, good discussion here as experienced by kata-containers: kata-containers/packaging#693

We can see that the CI build logs indicate that it failed & was using the 4.14 as well.

default-vmlinux.bin: OK
--
  | chmod 0400 default-vmlinux.bin
  | _submodules/firecracker/tools/devtool -y build_kernel --config tools/kernel-configs/microvm-kernel-aarch64-4.14.config

The solution for this issue needs 2 parts:

1. guest kernel configs need the missing property
2. whatever kernel we choose needs to have ptp_kvm commit: https://github.com/torvalds/linux/blob/16a8829130ca22666ac6236178a6233208d425c3/Documentation/virt/kvm/arm/ptp_kvm.rst#L4

[fangn2]

@BinSquare Thanks for taking a look at the issue.
The two parts solution makes sense to me. I did try compiling the kernel with

CONFIG_PTP_1588_CLOCK=y
CONFIG_PTP_1588_CLOCK_KVM=y

But since we don't have the ptp_kvm patch, the change did not make any difference.