Commit 9ff4cfb3 authored Apr 20, 2011 by Carsten Otte Committed by Martin Schwidefsky Apr 20, 2011

[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>

parent c7a29e56

arch/s390/kvm/sie64a.S

+2 −2

Original line number	Diff line number	Diff line
		@@ -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

		/*

Admin message