[PATCH v3 0/9] KVM: s390: More memory management fixes

From: Claudio Imbrenda

Date: Tue Mar 24 2026 - 13:43:44 EST


This series fixes some bugs that have been recently introduced with the
big gmap rewrite.

Most of the fixes are related to vSIE (nested guests), although some
are more general. The last patch fixes an issue introduced last year.

v2->v3
* fix a typo in the code (missin negation in patch 2)
* fix pre-existing alignment issue in _gmap_crstep_xchg_atomic()
* fix nested guest memory shadowing
* properly handle another possible place in _do_shadow_crste() where an
unshadowing event could be triggered
* fix _gaccess_do_shadow() to properly handle the case of real-address
asces for the nested guest
* fix some typos

v1->v2
* propagate vsie notification bit when splitting a large page
* replace gmap_crstep_xchg() with gmap_crstep_xchg_atomic(); let the
callers properly deal with races
* do not attempt to protect guest page table when the nested guest is
running in a real address space
* fix return value of KVM_S390_VCPU_FAULT in case of error


Claudio Imbrenda (9):
KVM: s390: vsie: Fix dat_split_ste()
KVM: s390: Remove non-atomic dat_crstep_xchg()
KVM: s390: vsie: Fix check for pre-existing shadow mapping
KVM: s390: vsie: Fix nested guest memory shadowing
KVM: s390: Fix gmap_link()
KVM: s390: vsie: Fix refcount overflow for shadow gmaps
KVM: s390: vsie: Fix unshadowing while shadowing
KVM: s390: vsie: Fix guest page tables protection
KVM: s390: Fix KVM_S390_VCPU_FAULT ioctl

arch/s390/kvm/dat.c | 102 +++++----------------------
arch/s390/kvm/dat.h | 11 +--
arch/s390/kvm/gaccess.c | 58 ++++++++++-----
arch/s390/kvm/gmap.c | 149 +++++++++++++++++++++++++++++----------
arch/s390/kvm/gmap.h | 26 +++----
arch/s390/kvm/kvm-s390.c | 18 ++++-
arch/s390/kvm/vsie.c | 4 +-
7 files changed, 204 insertions(+), 164 deletions(-)

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2.53.0