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[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>
This commit is contained in:
Carsten Otte 2011-04-20 10:15:36 +02:00 committed by Martin Schwidefsky
parent c7a29e56f0
commit 9ff4cfb3fc
1 changed files with 2 additions and 2 deletions
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4
arch/s390/kvm/sie64a.S
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@ -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
/*