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From: Cornelia Huck <cohuck@redhat.com>
To: Heiko Carstens <hca@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>,
	Janosch Frank <frankja@linux.vnet.ibm.com>,
	David Hildenbrand <david@redhat.com>,
	Claudio Imbrenda <imbrenda@linux.ibm.com>,
	kvm@vger.kernel.org, linux-s390@vger.kernel.org
Subject: Re: [PATCH] KVM: s390: fix guarded storage control register handling
Date: Thu, 15 Apr 2021 11:01:34 +0200	[thread overview]
Message-ID: <20210415110134.46136db2.cohuck@redhat.com> (raw)
In-Reply-To: <20210415080127.1061275-1-hca@linux.ibm.com>

On Thu, 15 Apr 2021 10:01:27 +0200
Heiko Carstens <hca@linux.ibm.com> wrote:

> store_regs_fmt2() has an ordering problem: first the guarded storage
> facility is enabled on the local cpu, then preemption disabled, and
> then the STGSC (store guarded storage controls) instruction is
> executed.
> 
> If the process gets scheduled away between enabling the guarded
> storage facility and before preemption is disabled, this might lead to
> a special operation exception and therefore kernel crash as soon as
> the process is scheduled back and the STGSC instruction is executed.
> 
> Fixes: 4e0b1ab72b8a ("KVM: s390: gs support for kvm guests")
> Cc: <stable@vger.kernel.org> # 4.12
> Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
> ---
>  arch/s390/kvm/kvm-s390.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)

Reviewed-by: Cornelia Huck <cohuck@redhat.com>


  parent reply	other threads:[~2021-04-15  9:01 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-15  8:01 [PATCH] KVM: s390: fix guarded storage control register handling Heiko Carstens
2021-04-15  8:35 ` David Hildenbrand
2021-04-15  8:39 ` Janosch Frank
2021-04-15  9:01 ` Cornelia Huck [this message]
2021-04-15 10:50 ` Christian Borntraeger

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