Message-ID: <e63d3848-ffa3-3a74-8e14-00e86e4935be@linux.ibm.com>
Date:   Tue, 7 Feb 2023 16:55:59 +0100
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Subject: Re: [PATCH v7 13/14] Documentation: KVM: s390: Describe
 KVM_S390_MEMOP_F_CMPXCHG
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To:     Janis Schoetterl-Glausch <scgl@linux.ibm.com>,
        Christian Borntraeger <borntraeger@linux.ibm.com>,
        Claudio Imbrenda <imbrenda@linux.ibm.com>,
        Heiko Carstens <hca@linux.ibm.com>,
        Vasily Gorbik <gor@linux.ibm.com>,
        Alexander Gordeev <agordeev@linux.ibm.com>
Cc:     David Hildenbrand <david@redhat.com>,
        Jonathan Corbet <corbet@lwn.net>, kvm@vger.kernel.org,
        linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-kselftest@vger.kernel.org, linux-s390@vger.kernel.org,
        Paolo Bonzini <pbonzini@redhat.com>,
        Shuah Khan <shuah@kernel.org>,
        Sven Schnelle <svens@linux.ibm.com>
References: <20230206164602.138068-1-scgl@linux.ibm.com>
 <20230206164602.138068-14-scgl@linux.ibm.com>
From:   Janosch Frank <frankja@linux.ibm.com>
In-Reply-To: <20230206164602.138068-14-scgl@linux.ibm.com>
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Precedence: bulk

On 2/6/23 17:46, Janis Schoetterl-Glausch wrote:
> Describe the semantics of the new KVM_S390_MEMOP_F_CMPXCHG flag for
> absolute vm write memops which allows user space to perform (storage key
> checked) cmpxchg operations on guest memory.
> 
> Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
> ---
>   Documentation/virt/kvm/api.rst | 29 ++++++++++++++++++++++++++---
>   1 file changed, 26 insertions(+), 3 deletions(-)
> 
> diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
> index 0a67cb738013..d09d7223c2a6 100644
> --- a/Documentation/virt/kvm/api.rst
> +++ b/Documentation/virt/kvm/api.rst
> @@ -3736,7 +3736,8 @@ The fields in each entry are defined as follows:
>   :Parameters: struct kvm_s390_mem_op (in)
>   :Returns: = 0 on success,
>             < 0 on generic error (e.g. -EFAULT or -ENOMEM),
> -          > 0 if an exception occurred while walking the page tables
> +          16 bit program exception code if the access causes such an exception,
> +          other code > 0xffff with special meaning.
>   

The 0xffff part is rebase damage from an old patch, I've discussed it 
off list and will remove that line when picking since I see no other 
reason for a re-spin.

Reviewed-by: Janosch Frank <frankja@linux.ibm.com>