From fe752331d4b361d43cfd0b89534b4b2176057c32 Mon Sep 17 00:00:00 2001 From: Christian Borntraeger Date: Wed, 20 Dec 2023 13:53:17 +0100 Subject: KVM: s390: vsie: fix race during shadow creation Right now it is possible to see gmap->private being zero in kvm_s390_vsie_gmap_notifier resulting in a crash. This is due to the fact that we add gmap->private == kvm after creation: static int acquire_gmap_shadow(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) { [...] gmap = gmap_shadow(vcpu->arch.gmap, asce, edat); if (IS_ERR(gmap)) return PTR_ERR(gmap); gmap->private = vcpu->kvm; Let children inherit the private field of the parent. Reported-by: Marc Hartmayer Fixes: a3508fbe9dc6 ("KVM: s390: vsie: initial support for nested virtualization") Cc: Cc: David Hildenbrand Reviewed-by: Janosch Frank Reviewed-by: David Hildenbrand Reviewed-by: Claudio Imbrenda Signed-off-by: Christian Borntraeger Link: https://lore.kernel.org/r/20231220125317.4258-1-borntraeger@linux.ibm.com --- arch/s390/kvm/vsie.c | 1 - arch/s390/mm/gmap.c | 1 + 2 files changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c index 8207a892bbe2..db9a180de65f 100644 --- a/arch/s390/kvm/vsie.c +++ b/arch/s390/kvm/vsie.c @@ -1220,7 +1220,6 @@ static int acquire_gmap_shadow(struct kvm_vcpu *vcpu, gmap = gmap_shadow(vcpu->arch.gmap, asce, edat); if (IS_ERR(gmap)) return PTR_ERR(gmap); - gmap->private = vcpu->kvm; vcpu->kvm->stat.gmap_shadow_create++; WRITE_ONCE(vsie_page->gmap, gmap); return 0; diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c index 6f96b5a71c63..8da39deb56ca 100644 --- a/arch/s390/mm/gmap.c +++ b/arch/s390/mm/gmap.c @@ -1691,6 +1691,7 @@ struct gmap *gmap_shadow(struct gmap *parent, unsigned long asce, return ERR_PTR(-ENOMEM); new->mm = parent->mm; new->parent = gmap_get(parent); + new->private = parent->private; new->orig_asce = asce; new->edat_level = edat_level; new->initialized = false; -- cgit From 83303a4c776ce1032d88df59e811183479acea77 Mon Sep 17 00:00:00 2001 From: Eric Farman Date: Fri, 1 Dec 2023 19:16:57 +0100 Subject: KVM: s390: fix cc for successful PQAP The various errors that are possible when processing a PQAP instruction (the absence of a driver hook, an error FROM that hook), all correctly set the PSW condition code to 3. But if that processing works successfully, CC0 needs to be set to convey that everything was fine. Fix the check so that the guest can examine the condition code to determine whether GPR1 has meaningful data. Fixes: e5282de93105 ("s390: ap: kvm: add PQAP interception for AQIC") Signed-off-by: Eric Farman Reviewed-by: Tony Krowiak Reviewed-by: Halil Pasic Link: https://lore.kernel.org/r/20231201181657.1614645-1-farman@linux.ibm.com Signed-off-by: Janosch Frank Message-Id: <20231201181657.1614645-1-farman@linux.ibm.com> Signed-off-by: Christian Borntraeger --- arch/s390/kvm/priv.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c index 621a17fd1a1b..f875a404a0a0 100644 --- a/arch/s390/kvm/priv.c +++ b/arch/s390/kvm/priv.c @@ -676,8 +676,12 @@ static int handle_pqap(struct kvm_vcpu *vcpu) if (vcpu->kvm->arch.crypto.pqap_hook) { pqap_hook = *vcpu->kvm->arch.crypto.pqap_hook; ret = pqap_hook(vcpu); - if (!ret && vcpu->run->s.regs.gprs[1] & 0x00ff0000) - kvm_s390_set_psw_cc(vcpu, 3); + if (!ret) { + if (vcpu->run->s.regs.gprs[1] & 0x00ff0000) + kvm_s390_set_psw_cc(vcpu, 3); + else + kvm_s390_set_psw_cc(vcpu, 0); + } up_read(&vcpu->kvm->arch.crypto.pqap_hook_rwsem); return ret; } -- cgit