| From 2f388ce5f4677670ce324b09c3f20494e74b40e9 Mon Sep 17 00:00:00 2001 |
| From: David Hildenbrand <david@redhat.com> |
| 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 |
| environments. |
| |
| Identified by manual code inspection. |
| |
| Fixes: a3508fbe9dc6 ("KVM: s390: vsie: initial support for nested virtualization") |
| Cc: <stable@vger.kernel.org> # v4.8+ |
| Signed-off-by: David Hildenbrand <david@redhat.com> |
| Link: https://lore.kernel.org/r/20200403153050.20569-3-david@redhat.com |
| Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com> |
| Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> |
| [borntraeger@de.ibm.com: fix patch description] |
| Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> |
| Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> |
| |
| 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; |
| } |
| -- |
| 2.7.4 |
| |
