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

/*



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