Messages in this thread | | | Date | Thu, 24 Nov 2022 11:46:38 +0100 | Subject | Re: [PATCH] KVM: s390: vsie: Fix the initialization of the epoch extension (epdx) field | From | Thomas Huth <> |
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On 24/11/2022 11.27, Janosch Frank wrote: > On 11/23/22 10:08, Thomas Huth wrote: >> We recently experienced some weird huge time jumps in nested guests when >> rebooting them in certain cases. After adding some debug code to the epoch >> handling in vsie.c (thanks to David Hildenbrand for the idea!), it was >> obvious that the "epdx" field (the multi-epoch extension) did not get set >> to 0xff in case the "epoch" field was negative. >> Seems like the code misses to copy the value from the epdx field from >> the guest to the shadow control block. By doing so, the weird time >> jumps are gone in our scenarios. >> >> Link: https://bugzilla.redhat.com/show_bug.cgi?id=2140899 >> Fixes: 8fa1696ea781 ("KVM: s390: Multiple Epoch Facility support") >> Signed-off-by: Thomas Huth <thuth@redhat.com> > > Could you please add a test for this to the KVM unit tests? > I'd guess you might already have some code for it from your debugging sessions.
I don't have some test code for this yet - I was only testing with the scenario that is described in the bugzilla ticket. But sure, I can have a try to come up with a k-u-t test.
Thomas
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