From: Janosch Frank <frankja@linux.ibm.com>
To: Eric Farman <farman@linux.ibm.com>,
Christian Borntraeger <borntraeger@linux.ibm.com>,
Claudio Imbrenda <imbrenda@linux.ibm.com>,
David Hildenbrand <david@kernel.org>
Cc: kvm@vger.kernel.org, linux-s390@vger.kernel.org
Subject: Re: [PATCH v2 1/3] KVM: s390: Toggle operation exception for userspace
Date: Mon, 11 May 2026 10:08:22 +0200 [thread overview]
Message-ID: <c7655af3-9705-487c-add2-dd31d8bc6623@linux.ibm.com> (raw)
In-Reply-To: <20260507200836.3500368-2-farman@linux.ibm.com>
On 5/7/26 22:08, Eric Farman wrote:
> The KVM_CAP_S390_USER_OPEREXEC capability allows operation exceptions
> to be forwarded to userspace. But the actual enablement at the hardware
> level occurs in kvm_arch_vcpu_postcreate(), and only if STFLE.74 or
> user_instr0 are enabled. The latter is associated with a separate
> capability (KVM_CAP_S390_USER_INSTR0), so the only way this happens
> for the USER_OPEREXEC capability is if STFLE.74 is enabled. KVM
> unconditionally enables this bit in kvm_arch_init_vm(), but the guest
> could disable it from the CPU model and thus ignore this capability.
>
> Add USER_OPEREXEC to the check in kvm_arch_vcpu_postcreate(), such that
> either capability would enable this type of exception.
>
Naming wise shouldn't this be something like:
KVM: s390: Fix S390_USER_OPEREXEC enablement without stfle 74
?
next prev parent reply other threads:[~2026-05-11 8:08 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-07 20:08 [PATCH v2 0/3] KVM: s390: Toggle operation exception for userspace Eric Farman
2026-05-07 20:08 ` [PATCH v2 1/3] " Eric Farman
2026-05-08 9:54 ` Christian Borntraeger
2026-05-11 8:01 ` Janosch Frank
2026-05-11 8:08 ` Janosch Frank [this message]
2026-05-11 12:56 ` Eric Farman
2026-05-07 20:08 ` [PATCH v2 2/3] KVM: s390: selftests: Extended user_operexec tests Eric Farman
2026-05-08 10:05 ` Christian Borntraeger
2026-05-08 10:30 ` Claudio Imbrenda
2026-05-11 8:04 ` Janosch Frank
2026-05-07 20:08 ` [PATCH v2 3/3] KVM: s390: Fix typo in UCONTROL documentation Eric Farman
2026-05-08 10:29 ` Claudio Imbrenda
2026-05-11 10:59 ` Hendrik Brueckner
2026-05-08 10:07 ` [PATCH v2 0/3] KVM: s390: Toggle operation exception for userspace Christian Borntraeger
2026-05-08 13:08 ` Eric Farman
2026-05-08 14:50 ` Christian Borntraeger
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