From: Claudio Imbrenda <imbrenda@linux.ibm.com>
To: linux-kernel@vger.kernel.org
Cc: kvm@vger.kernel.org, linux-s390@vger.kernel.org,
borntraeger@de.ibm.com, frankja@linux.ibm.com, nrb@linux.ibm.com,
seiden@linux.ibm.com, schlameuss@linux.ibm.com,
gra@linux.ibm.com, david@kernel.org
Subject: [PATCH v3 0/6] KVM: s390: Enable 4k granularity for memslots
Date: Thu, 2 Apr 2026 17:01:29 +0200 [thread overview]
Message-ID: <20260402150135.196943-1-imbrenda@linux.ibm.com> (raw)
Currently the memslot granularity for s390 VMs is 1M. Both the s390
core architecture and virtio-mem only support a 1M granularity for
guest memory.
Notwithstanding the official architectural limits, it can be beneficial
to support memslots with 4k granularity. With the new gmap code, this
is a quite simple change. This allows us to enable more existing
selftests and makes KVM on s390 more future proof.
v2->v3
* Remove more 1M-alignment #ifdefs in the kvm selftests.
* Do not remove the common tests from loongarch, since loongarch does
not include the common tests by default.
* Opportunistically fix a potential NULL pointer dereference when
memslots for UCONTROL guests are attempted to be removed (does not
actually happen in practice).
v1->v2
* Fixed the first patch (thanks Christian)
Claudio Imbrenda (6):
KVM: s390: Add some useful mask macros
KVM: s390: Add alignment checks for hugepages
KVM: s390: Allow 4k granularity for memslots
KVM: selftests: Remove 1M alignment requirement for s390
KVM: s390: selftests: enable some common memory-related tests
KVM: s390: ucontrol: Fix memslot handling
arch/s390/kvm/dat.h | 5 +++
arch/s390/kvm/faultin.c | 2 +-
arch/s390/kvm/gaccess.c | 2 +-
arch/s390/kvm/gmap.c | 32 +++++++++++++++----
arch/s390/kvm/gmap.h | 3 +-
arch/s390/kvm/kvm-s390.c | 22 ++++---------
tools/testing/selftests/kvm/Makefile.kvm | 9 ++----
tools/testing/selftests/kvm/dirty_log_test.c | 3 --
.../testing/selftests/kvm/include/kvm_util.h | 4 ---
.../selftests/kvm/kvm_page_table_test.c | 3 --
tools/testing/selftests/kvm/lib/kvm_util.c | 9 +-----
tools/testing/selftests/kvm/lib/memstress.c | 4 ---
.../selftests/kvm/pre_fault_memory_test.c | 4 ---
.../selftests/kvm/set_memory_region_test.c | 9 +-----
14 files changed, 47 insertions(+), 64 deletions(-)
--
2.53.0
next reply other threads:[~2026-04-02 15:01 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-02 15:01 Claudio Imbrenda [this message]
2026-04-02 15:01 ` [PATCH v3 1/6] KVM: s390: Add some useful mask macros Claudio Imbrenda
2026-04-07 12:13 ` Steffen Eiden
2026-04-09 13:41 ` Christoph Schlameuss
2026-04-02 15:01 ` [PATCH v3 2/6] KVM: s390: Add alignment checks for hugepages Claudio Imbrenda
2026-04-07 12:30 ` Steffen Eiden
2026-04-10 9:15 ` Christoph Schlameuss
2026-04-02 15:01 ` [PATCH v3 3/6] KVM: s390: Allow 4k granularity for memslots Claudio Imbrenda
2026-04-07 12:33 ` Steffen Eiden
2026-04-10 10:02 ` Christoph Schlameuss
2026-04-02 15:01 ` [PATCH v3 4/6] KVM: selftests: Remove 1M alignment requirement for s390 Claudio Imbrenda
2026-04-07 12:44 ` Steffen Eiden
2026-04-10 11:28 ` Christoph Schlameuss
2026-04-02 15:01 ` [PATCH v3 5/6] KVM: s390: selftests: enable some common memory-related tests Claudio Imbrenda
2026-04-07 12:47 ` Steffen Eiden
2026-04-07 13:04 ` Claudio Imbrenda
2026-04-07 13:41 ` Steffen Eiden
2026-04-07 15:19 ` Steffen Eiden
2026-04-09 8:50 ` Claudio Imbrenda
2026-04-10 12:02 ` Christoph Schlameuss
2026-04-02 15:01 ` [PATCH v3 6/6] KVM: s390: ucontrol: Fix memslot handling Claudio Imbrenda
2026-04-07 12:55 ` Steffen Eiden
2026-04-07 13:05 ` Claudio Imbrenda
2026-04-10 9:25 ` Christoph Schlameuss
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