Messages in this thread | | | Subject | Re: [PATCH v3 03/14] KVM: s390: pv: leak the ASCE page when destroy fails | From | David Hildenbrand <> | Date | Fri, 6 Aug 2021 13:39:07 +0200 |
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On 06.08.21 11:32, Claudio Imbrenda wrote: > On Fri, 6 Aug 2021 09:31:54 +0200 > David Hildenbrand <david@redhat.com> wrote: > >> On 04.08.21 17:40, Claudio Imbrenda wrote: >>> When a protected VM is created, the topmost level of page tables of >>> its ASCE is marked by the Ultravisor; any attempt to use that >>> memory for protected virtualization will result in failure. >>> >>> Only a successful Destroy Configuration UVC will remove the marking. >>> >>> When the Destroy Configuration UVC fails, the topmost level of page >>> tables of the VM does not get its marking cleared; to avoid issues >>> it must not be used again. >>> >>> Since the page becomes in practice unusable, we set it aside and >>> leak it. >> >> Instead of leaking, can't we add it to some list and try again later? >> Or do we only expect permanent errors? > > once the secure VM has been destroyed unsuccessfully, there is nothing > that can be done, this is a permanent error > >> Also, we really should bail out loud (pr_warn) to tell the admin that >> something really nasty is going on. > > when a destroy secure VM UVC fails, there are already other warnings > printed, no need to add one more >
Okay, makes sense then to me, thanks! Might be worth adding some of that info to the patch description.
-- Thanks,
David / dhildenb
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