linux-kernel - Re: [PATCH v2 0/2] Dirtying, failing memop: don't indicate suppression

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Message-ID: <13d0d706-abc4-3e4d-88c3-6447636fd1fd@linux.ibm.com>
Date:   Mon, 25 Apr 2022 19:29:16 +0200
From:   Janis Schoetterl-Glausch <scgl@...ux.ibm.com>
To:     Christian Borntraeger <borntraeger@...ux.ibm.com>,
        Janosch Frank <frankja@...ux.ibm.com>,
        Claudio Imbrenda <imbrenda@...ux.ibm.com>
Cc:     David Hildenbrand <david@...hat.com>,
        Heiko Carstens <hca@...ux.ibm.com>,
        Vasily Gorbik <gor@...ux.ibm.com>,
        Alexander Gordeev <agordeev@...ux.ibm.com>,
        Sven Schnelle <svens@...ux.ibm.com>,
        Paolo Bonzini <pbonzini@...hat.com>, kvm@...r.kernel.org,
        Shuah Khan <shuah@...nel.org>, linux-kselftest@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-s390@...r.kernel.org
Subject: Re: [PATCH v2 0/2] Dirtying, failing memop: don't indicate
 suppression

On 4/25/22 18:30, Christian Borntraeger wrote:
> Am 25.04.22 um 12:01 schrieb Janis Schoetterl-Glausch:
>> If a memop fails due to key checked protection, after already having
>> written to the guest, don't indicate suppression to the guest, as that
>> would imply that memory wasn't modified.
>>
>> This could be considered a fix to the code introducing storage key
>> support, however this is a bug in KVM only if we emulate an
>> instructions writing to an operand spanning multiple pages, which I
>> don't believe we do.
>>
> 
> Thanks applied. I think it makes sense for 5.18 nevertheless.

Janosch had some concerns because the protection code being 000 implies
that the effective address in the TEID is unpredictable.
Let's see if he chimes in.

> 
>> v1 -> v2
>>   * Reword commit message of patch 1
>>
>> Janis Schoetterl-Glausch (2):
>>    KVM: s390: Don't indicate suppression on dirtying, failing memop
>>    KVM: s390: selftest: Test suppression indication on key prot exception
>>
>>   arch/s390/kvm/gaccess.c                   | 47 ++++++++++++++---------
>>   tools/testing/selftests/kvm/s390x/memop.c | 43 ++++++++++++++++++++-
>>   2 files changed, 70 insertions(+), 20 deletions(-)
>>
>>
>> base-commit: af2d861d4cd2a4da5137f795ee3509e6f944a25b
>