[PATCH] kvm-s390: Fix problem state handling in guest sigp handler

[Christian Borntraeger <borntraeger@de.ibm.com>]

Hello Avi,

this patch should go into 2.6.28-rcx. It fixes an important guest bug.

-
From: Christian Borntraeger <borntraeger@de.ibm.com>

We can get an exit for instructions starting with 0xae, even if the guest is
in userspace. Lets make sure, that the signal processor handler is only called
in guest supervisor mode. Otherwise, send a program check.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
---
 arch/s390/kvm/sigp.c |    5 +++++
 1 file changed, 5 insertions(+)

Index: kvm/arch/s390/kvm/sigp.c
===================================================================
--- kvm.orig/arch/s390/kvm/sigp.c
+++ kvm/arch/s390/kvm/sigp.c
@@ -237,6 +237,11 @@ int kvm_s390_handle_sigp(struct kvm_vcpu
 	u8 order_code;
 	int rc;
 
+	/* sigp in userspace can exit */
+	if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE)
+		return kvm_s390_inject_program_int(vcpu,
+						   PGM_PRIVILEGED_OPERATION);
+
 	order_code = disp2;
 	if (base2)
 		order_code += vcpu->arch.guest_gprs[base2];