From 6f93d1ed6f46b7b0be288cc45250d67bceb28982 Mon Sep 17 00:00:00 2001 From: Claudio Imbrenda Date: Thu, 26 Mar 2026 14:17:12 +0100 Subject: [PATCH] KVM: s390: vsie: Fix check for pre-existing shadow mapping When shadowing a nested guest, a check is performed and no shadowing is attempted if the nested guest is already shadowed. The existing check was incomplete; fix it by also checking whether the leaf DAT table entry in the existing shadow gmap has the same protection as the one specified in the guest DAT entry. Fixes: e38c884df921 ("KVM: s390: Switch to new gmap") Reviewed-by: Steffen Eiden Reviewed-by: Janosch Frank Signed-off-by: Claudio Imbrenda --- arch/s390/kvm/gaccess.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/s390/kvm/gaccess.c b/arch/s390/kvm/gaccess.c index 4ee862424ca0..8fd690255e1b 100644 --- a/arch/s390/kvm/gaccess.c +++ b/arch/s390/kvm/gaccess.c @@ -1506,8 +1506,9 @@ static int _gaccess_do_shadow(struct kvm_s390_mmu_cache *mc, struct gmap *sg, if (rc) return rc; - /* A race occourred. The shadow mapping is already valid, nothing to do */ - if ((ptep && !ptep->h.i) || (!ptep && crste_leaf(*table))) + /* A race occurred. The shadow mapping is already valid, nothing to do */ + if ((ptep && !ptep->h.i && ptep->h.p == w->p) || + (!ptep && crste_leaf(*table) && !table->h.i && table->h.p == w->p)) return 0; gl = get_level(table, ptep);