Messages in this thread | | | Date | Thu, 5 May 2022 19:10:39 +0200 | From | Thomas Huth <> | Subject | Re: [PATCH v10 02/19] KVM: s390: pv: handle secure storage violations for protected guests |
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On 14/04/2022 10.02, Claudio Imbrenda wrote: > With upcoming patches, protected guests will be able to trigger secure > storage violations in normal operation. > > A secure storage violation is triggered when a protected guest tries to > access secure memory that has been mapped erroneously, or that belongs > to a different protected guest or to the ultravisor. > > With upcoming patches, protected guests will be able to trigger secure > storage violations in normal operation.
You've already used this sentence as 1st sentence of the patch description. Looks weird to read it again. Maybe scratch the 1st sentence?
> This happens for example if a > protected guest is rebooted with lazy destroy enabled and the new guest > is also protected. > > When the new protected guest touches pages that have not yet been > destroyed, and thus are accounted to the previous protected guest, a > secure storage violation is raised. > > This patch adds handling of secure storage violations for protected > guests. > > This exception is handled by first trying to destroy the page, because > it is expected to belong to a defunct protected guest where a destroy > should be possible. If that fails, a normal export of the page is > attempted. > > Therefore, pages that trigger the exception will be made non-secure > before attempting to use them again for a different secure guest.
I'm an complete ignorant here, but isn't this somewhat dangerous? Could it happen that a VM could destroy/export the pages of another secure guest that way?
Thomas
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