From: Martin Schwidefsky <schwidefsky@de.ibm.com>
To: Avi Kivity <avi@redhat.com>
Cc: Carsten Otte <cotte@de.ibm.com>,
Marcelo Tossati <mtosatti@redhat.com>,
Christian Borntraeger <borntraeger@de.ibm.com>,
Heiko Carstens <heiko.carstens@de.ibm.com>,
Cornelia Huck <cornelia.huck@de.ibm.com>,
KVM <kvm@vger.kernel.org>,
Joachim von Buttlar <joachim_von_buttlar@de.ibm.com>,
Jens Freimann <jfrei@de.ibm.com>,
Constantin Werner <constantin.werner@de.ibm.com>
Subject: Re: [patch 01/12] [PATCH] kvm-s390: ioctl to switch to user controlled virtual machines
Date: Thu, 1 Dec 2011 15:20:16 +0100 [thread overview]
Message-ID: <20111201152016.6de7eea3@de.ibm.com> (raw)
In-Reply-To: <4ED77DD7.7090507@redhat.com>
On Thu, 01 Dec 2011 15:15:03 +0200
Avi Kivity <avi@redhat.com> wrote:
> > +
> > + if (kvm->arch.gmap)
> > + gmap_free(kvm->arch.gmap);
> > +
> > + kvm->arch.gmap = NULL;
>
> Locking?
>
> What happens if a vcpu is created afterwards?
>
> I guess you don't mind too much since this is a privileged interface for
> a single purpose.
That is indeed a race. A malicious user space could create a new cpu with
KVM_CREATE_VCPU on another thread after the for loop checked that there
are no VCPUs. The new VCPU could then pick up the kvm->arch.gmap and use it
while the caller of KVM_S390_ENABLE_UCONTROL frees the structure.
The kvm_s390_enable_ucontrol function needs to lock with the kvm->lock mutex.
--
blue skies,
Martin.
"Reality continues to ruin my life." - Calvin.
next prev parent reply other threads:[~2011-12-01 14:20 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-01 12:57 [patch 00/12] User controlled virtual machines Carsten Otte
2011-12-01 12:57 ` [patch 01/12] [PATCH] kvm-s390: ioctl to switch to user " Carsten Otte
2011-12-01 13:15 ` Avi Kivity
2011-12-01 13:31 ` Avi Kivity
2011-12-01 14:20 ` Martin Schwidefsky [this message]
2011-12-01 12:57 ` [patch 02/12] [PATCH] kvm-s390-ucontrol: per vcpu address spaces Carsten Otte
2011-12-01 13:19 ` Avi Kivity
2011-12-01 12:57 ` [patch 03/12] [PATCH] kvm-s390-ucontrol: export page faults to user Carsten Otte
2011-12-01 12:57 ` [patch 04/12] [PATCH] kvm-s390-ucontrol: export SIE control block " Carsten Otte
2011-12-01 13:25 ` Avi Kivity
2011-12-01 13:26 ` Avi Kivity
2011-12-01 13:59 ` Carsten Otte
2011-12-01 14:04 ` Avi Kivity
2011-12-01 12:57 ` [patch 05/12] [PATCH] kvm-s390-ucontrol: disable in-kernel handling of SIE intercepts Carsten Otte
2011-12-01 12:57 ` [patch 06/12] [PATCH] kvm-s390-ucontrol: disable in-kernel irq stack Carsten Otte
2011-12-01 12:57 ` [patch 07/12] [PATCH] kvm-s390-ucontrol: interface to inject faults on a vcpu page table Carsten Otte
2011-12-01 12:57 ` [patch 08/12] [PATCH] kvm-s390-ucontrol: disable sca Carsten Otte
2011-12-01 12:57 ` [patch 09/12] [PATCH] kvm-s390: fix assumption for KVM_MAX_VCPUS Carsten Otte
2011-12-01 12:57 ` [patch 10/12] [PATCH] kvm-s390: storage key interface Carsten Otte
2011-12-01 12:57 ` [patch 11/12] [PATCH] kvm-s390-ucontrol: announce capability for user controlled vms Carsten Otte
2011-12-01 12:57 ` [patch 12/12] From: Carsten Otte <cotte@de.ibm.com> Carsten Otte
2011-12-01 13:10 ` [patch 00/12] User controlled virtual machines Avi Kivity
2011-12-01 13:33 ` Avi Kivity
2011-12-02 11:52 ` Carsten Otte
-- strict thread matches above, loose matches on Subject: below --
2011-12-08 9:12 [patch 00/12] Ucontrol patchset V2 Carsten Otte
2011-12-08 9:12 ` [patch 01/12] [PATCH] kvm-s390: ioctl to switch to user controlled virtual machines Carsten Otte
2011-12-08 9:25 ` Sasha Levin
2011-12-08 9:27 ` Carsten Otte
2011-12-08 9:45 ` Avi Kivity
2011-12-08 9:53 ` Sasha Levin
2011-12-08 9:59 ` Avi Kivity
2011-12-08 10:18 ` Alexander Graf
2011-12-08 11:48 ` Carsten Otte
2011-12-08 13:16 ` Alexander Graf
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