LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Claudio Imbrenda <imbrenda@linux.ibm.com>
To: David Hildenbrand <david@redhat.com>
Cc: kvm@vger.kernel.org, cohuck@redhat.com, borntraeger@de.ibm.com,
	frankja@linux.ibm.com, thuth@redhat.com, pasic@linux.ibm.com,
	linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org,
	Ulrich.Weigand@de.ibm.com
Subject: Re: [PATCH v3 03/14] KVM: s390: pv: leak the ASCE page when destroy fails
Date: Fri, 6 Aug 2021 11:32:44 +0200	[thread overview]
Message-ID: <20210806113244.4d0712d2@p-imbrenda> (raw)
In-Reply-To: <6b75cc71-b996-cf3d-ce57-dbcd475ebc3a@redhat.com>

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


  reply	other threads:[~2021-08-06  9:40 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-04 15:40 [PATCH v3 00/14] KVM: s390: pv: implement lazy destroy Claudio Imbrenda
2021-08-04 15:40 ` [PATCH v3 01/14] KVM: s390: pv: add macros for UVC CC values Claudio Imbrenda
2021-08-06  7:26   ` David Hildenbrand
2021-08-06  9:34     ` Claudio Imbrenda
2021-08-06 15:15     ` Janosch Frank
2021-08-04 15:40 ` [PATCH v3 02/14] KVM: s390: pv: avoid stall notifications for some UVCs Claudio Imbrenda
2021-08-06  7:30   ` David Hildenbrand
2021-08-06  9:33     ` Claudio Imbrenda
2021-08-04 15:40 ` [PATCH v3 03/14] KVM: s390: pv: leak the ASCE page when destroy fails Claudio Imbrenda
2021-08-06  7:31   ` David Hildenbrand
2021-08-06  9:32     ` Claudio Imbrenda [this message]
2021-08-06 11:39       ` David Hildenbrand
2021-08-04 15:40 ` [PATCH v3 04/14] KVM: s390: pv: properly handle page flags for protected guests Claudio Imbrenda
2021-08-04 15:40 ` [PATCH v3 05/14] KVM: s390: pv: handle secure storage violations " Claudio Imbrenda
2021-08-04 15:40 ` [PATCH v3 06/14] KVM: s390: pv: handle secure storage exceptions for normal guests Claudio Imbrenda
2021-08-04 15:40 ` [PATCH v3 07/14] KVM: s390: pv: refactor s390_reset_acc Claudio Imbrenda
2021-08-04 15:40 ` [PATCH v3 08/14] KVM: s390: pv: usage counter instead of flag Claudio Imbrenda
2021-08-04 15:40 ` [PATCH v3 09/14] KVM: s390: pv: add export before import Claudio Imbrenda
2021-08-04 15:40 ` [PATCH v3 10/14] KVM: s390: pv: lazy destroy for reboot Claudio Imbrenda
2021-08-04 15:40 ` [PATCH v3 11/14] KVM: s390: pv: extend lazy destroy to handle shutdown Claudio Imbrenda
2021-08-04 15:40 ` [PATCH v3 12/14] KVM: s390: pv: module parameter to fence lazy destroy Claudio Imbrenda
2021-08-04 15:40 ` [PATCH v3 13/14] KVM: s390: pv: add OOM notifier for " Claudio Imbrenda
2021-08-04 15:40 ` [PATCH v3 14/14] KVM: s390: pv: avoid export before import if possible Claudio Imbrenda
2021-08-06  7:10 ` [PATCH v3 00/14] KVM: s390: pv: implement lazy destroy David Hildenbrand
2021-08-06  9:30   ` Claudio Imbrenda
2021-08-06 11:30     ` David Hildenbrand
2021-08-06 13:44       ` Claudio Imbrenda
2021-08-09  8:50         ` David Hildenbrand

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210806113244.4d0712d2@p-imbrenda \
    --to=imbrenda@linux.ibm.com \
    --cc=Ulrich.Weigand@de.ibm.com \
    --cc=borntraeger@de.ibm.com \
    --cc=cohuck@redhat.com \
    --cc=david@redhat.com \
    --cc=frankja@linux.ibm.com \
    --cc=kvm@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-s390@vger.kernel.org \
    --cc=pasic@linux.ibm.com \
    --cc=thuth@redhat.com \
    --subject='Re: [PATCH v3 03/14] KVM: s390: pv: leak the ASCE page when destroy fails' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).