blob: 23954c2774e10981a91035475f62e695ecd20b2a [file] [log] [blame]
From 2f388ce5f4677670ce324b09c3f20494e74b40e9 Mon Sep 17 00:00:00 2001
From: David Hildenbrand <>
Date: Fri, 3 Apr 2020 17:30:47 +0200
Subject: [PATCH] KVM: s390: vsie: Fix delivery of addressing exceptions
commit 4d4cee96fb7a3cc53702a9be8299bf525be4ee98 upstream.
Whenever we get an -EFAULT, we failed to read in guest 2 physical
address space. Such addressing exceptions are reported via a program
intercept to the nested hypervisor.
We faked the intercept, we have to return to guest 2. Instead, right
now we would be returning -EFAULT from the intercept handler, eventually
crashing the VM.
the correct thing to do is to return 1 as rc == 1 is the internal
representation of "we have to go back into g2".
Addressing exceptions can only happen if the g2->g3 page tables
reference invalid g2 addresses (say, either a table or the final page is
not accessible - so something that basically never happens in sane
Identified by manual code inspection.
Fixes: a3508fbe9dc6 ("KVM: s390: vsie: initial support for nested virtualization")
Cc: <> # v4.8+
Signed-off-by: David Hildenbrand <>
Reviewed-by: Claudio Imbrenda <>
Reviewed-by: Christian Borntraeger <>
[ fix patch description]
Signed-off-by: Christian Borntraeger <>
Signed-off-by: Paul Gortmaker <>
diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c
index 076090f9e666..4f6c22d72072 100644
--- a/arch/s390/kvm/vsie.c
+++ b/arch/s390/kvm/vsie.c
@@ -1202,6 +1202,7 @@ static int vsie_run(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
scb_s->iprcc = PGM_ADDRESSING;
scb_s->pgmilc = 4;
scb_s->gpsw.addr = __rewind_psw(scb_s->gpsw, 4);
+ rc = 1;
return rc;