[Qemu-devel] [PULL 2/3] s390x/kvm: fix small race reboot vs. cmma

[Christian Borntraeger <borntraeger@de.ibm.com>]

Right now we reset all devices before we reset the cmma states.  This
can result in the host kernel discarding guest pages that were
previously in the unused state but already contain a bios or a -kernel
file before the cmma reset has finished.  This race results in random
guest crashes or hangs during very early reboot.

Fixes: 1cd4e0f6f0a6 ("s390x/cmma: clean up cmma reset")
Cc: qemu-stable@nongnu.org
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
---
 hw/s390x/s390-virtio.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/s390x/s390-virtio.c b/hw/s390x/s390-virtio.c
index 0a96347..7a3a7fe 100644
--- a/hw/s390x/s390-virtio.c
+++ b/hw/s390x/s390-virtio.c
@@ -204,8 +204,8 @@ void s390_machine_reset(void)
 {
     S390CPU *ipl_cpu = S390_CPU(qemu_get_cpu(0));
 
-    qemu_devices_reset();
     s390_cmma_reset();
+    qemu_devices_reset();
     s390_crypto_reset();
 
     /* all cpus are stopped - configure and start the ipl cpu only */
-- 
2.7.4