Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Subject: Re: [PATCH] KVM: s390: Fix handle_sske page fault handling
To:     Janis Schoetterl-Glausch <scgl@linux.ibm.com>,
        Janosch Frank <frankja@linux.ibm.com>,
        Heiko Carstens <hca@linux.ibm.com>,
        Vasily Gorbik <gor@linux.ibm.com>
Cc:     David Hildenbrand <david@redhat.com>,
        Claudio Imbrenda <imbrenda@linux.ibm.com>,
        Alexander Gordeev <agordeev@linux.ibm.com>,
        kvm@vger.kernel.org, linux-s390@vger.kernel.org,
        linux-kernel@vger.kernel.org
References: <20211022112913.211986-1-scgl@linux.ibm.com>
 <723441ee-2744-32c3-1820-3307bf98fce5@de.ibm.com>
 <20211022152648.26536-1-scgl@linux.ibm.com>
From:   Christian Borntraeger <borntraeger@de.ibm.com>
Message-ID: <4c81140a-add0-8593-7941-55822b45df3c@de.ibm.com>
Date:   Mon, 25 Oct 2021 09:08:23 +0200
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101
 Thunderbird/78.14.0
MIME-Version: 1.0
In-Reply-To: <20211022152648.26536-1-scgl@linux.ibm.com>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Precedence: bulk

Am 22.10.21 um 17:26 schrieb Janis Schoetterl-Glausch:
> On Fri, Oct 22, 2021 at 02:00:13PM +0200, Christian Borntraeger wrote:
>> Am 22.10.21 um 13:29 schrieb Janis Schoetterl-Glausch:
>>> Retry if fixup_user_fault succeeds.
>>
>> Maybe rephrase that with a more verbose description (e.g. if fixup_user_fault succeeds
>> we return EAGAIN and thus we ust retry the loop and  blabla....)
>>
> Done
> 
> [...]
> -- >8 --
> Subject: [PATCH v2] KVM: s390: Fix handle_sske page fault handling
> 
> If handle_sske cannot set the storage key, because there is no
> page table entry or no present large page entry, it calls
> fixup_user_fault.
> However, currently, if the call succeeds, handle_sske returns
> -EAGAIN, without having set the storage key.
> Instead, retry by continue'ing the loop without incrementing the
> address.
> The same issue in handle_pfmf was fixed by
> a11bdb1a6b78 (KVM: s390: Fix pfmf and conditional skey emulation).
> 
> Fixes: bd096f644319 ("KVM: s390: Add skey emulation fault handling")
> Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
> Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
> Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
> ---
>   arch/s390/kvm/priv.c | 2 ++
>   1 file changed, 2 insertions(+)
> 
> diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c
> index 53da4ceb16a3..417154b314a6 100644
> --- a/arch/s390/kvm/priv.c
> +++ b/arch/s390/kvm/priv.c
> @@ -397,6 +397,8 @@ static int handle_sske(struct kvm_vcpu *vcpu)
>   		mmap_read_unlock(current->mm);
>   		if (rc == -EFAULT)
>   			return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
> +		if (rc == -EAGAIN)
> +			continue;
>   		if (rc < 0)
>   			return rc;
>   		start += PAGE_SIZE;
> 

thanks applied.