From: Christian Borntraeger <borntraeger@de.ibm.com>
Date: Mon, 20 Jan 2014 11:34:13 +0000 (+0100)
Subject: KVM: s390: Fix memory access error detection
X-Git-Tag: v3.14-rc1~127^2^2
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=699bde3b6c95319749a8e1b7aa2b3f6bee84bff8;p=linux.git

KVM: s390: Fix memory access error detection

Seems that commit 210b1607012cc9034841a393e0591b2c86d9e26c
(KVM: s390: Removed SIE_INTERCEPT_UCONTROL) lost a hunk when we
reworked our patch queue to rework the async_fp code. We now
ignore faults on the sie instruction (guest accesses non-existing
memory) instead of sending a fault into the guest. This leads to
hang situations with the old virtio transport that checks for
descriptor memory after guest memory. Instead of bailing out this
code now goes wild...
Lets re-add the check.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
---

diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 1bb1ddaf93c0..7635c00a1479 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -738,6 +738,10 @@ static int vcpu_post_run(struct kvm_vcpu *vcpu, int exit_reason)
 						current->thread.gmap_addr;
 		vcpu->run->s390_ucontrol.pgm_code = 0x10;
 		rc = -EREMOTE;
+	} else {
+		VCPU_EVENT(vcpu, 3, "%s", "fault in sie instruction");
+		trace_kvm_s390_sie_fault(vcpu);
+		rc = kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
 	}
 
 	memcpy(&vcpu->run->s.regs.gprs[14], &vcpu->arch.sie_block->gg14, 16);