[33/55] [S390] kvm-390: Let kernel exit SIE instruction on work

[Greg KH <gregkh@suse.de>]

2.6.38-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Carsten Otte <cotte@de.ibm.com>

commit 9ff4cfb3fcfd48b49fdd9be7381b3be340853aa4 upstream.

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

This patch fixes the sie exit on interrupts. The low level
interrupt handler returns to the PSW address in pt_regs and not
to the PSW address in the lowcore.
Without this fix a cpu bound guest might never leave guest state
since the host interrupt handler would blindly return to the
SIE instruction, even on need_resched and friends.

Signed-off-by: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 arch/s390/kvm/sie64a.S |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/arch/s390/kvm/sie64a.S
+++ b/arch/s390/kvm/sie64a.S
@@ -48,10 +48,10 @@ sie_irq_handler:
 	tm	__TI_flags+7(%r2),_TIF_EXIT_SIE
 	jz	0f
 	larl	%r2,sie_exit			# work pending, leave sie
-	stg	%r2,__LC_RETURN_PSW+8
+	stg	%r2,SPI_PSW+8(0,%r15)
 	br	%r14
 0:	larl	%r2,sie_reenter			# re-enter with guest id
-	stg	%r2,__LC_RETURN_PSW+8
+	stg	%r2,SPI_PSW+8(0,%r15)
 1:	br	%r14
 
 /*