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

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.

Cc: stable@kernel.org
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>

diff --git a/arch/s390/kvm/sie64a.S b/arch/s390/kvm/sie64a.S
index 7e9d30d567b0ab21265b669f1f343018d10de080..ab0e041ac54cf2b17fc0b631bf0ed6cd4f59fd53 100644 (file)
--- 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
 
 /*