linux-kernel - Re: [PATCH] KVM: s390: Fix handle

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Message-ID: <4c81140a-add0-8593-7941-55822b45df3c@de.ibm.com>
Date:   Mon, 25 Oct 2021 09:08:23 +0200
From:   Christian Borntraeger <borntraeger@...ibm.com>
To:     Janis Schoetterl-Glausch <scgl@...ux.ibm.com>,
        Janosch Frank <frankja@...ux.ibm.com>,
        Heiko Carstens <hca@...ux.ibm.com>,
        Vasily Gorbik <gor@...ux.ibm.com>
Cc:     David Hildenbrand <david@...hat.com>,
        Claudio Imbrenda <imbrenda@...ux.ibm.com>,
        Alexander Gordeev <agordeev@...ux.ibm.com>,
        kvm@...r.kernel.org, linux-s390@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] KVM: s390: Fix handle_sske page fault handling

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@...ux.ibm.com>
> Reviewed-by: Christian Borntraeger <borntraeger@...ibm.com>
> Reviewed-by: Claudio Imbrenda <imbrenda@...ux.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.