Re: [PATCH v3 03/14] KVM: s390: pv: leak the ASCE page when destroy fails
From: Claudio Imbrenda <imbrenda@linux.ibm.com>
Date: 2021-08-06 09:40:04
Also in:
linux-s390, lkml
From: Claudio Imbrenda <imbrenda@linux.ibm.com>
Date: 2021-08-06 09:40:04
Also in:
linux-s390, lkml
On Fri, 6 Aug 2021 09:31:54 +0200 David Hildenbrand [off-list ref] wrote:
On 04.08.21 17:40, Claudio Imbrenda wrote:quoted
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