Under PV, the guest's TOD clock is under control of the ultravisor and the
hypervisor cannot change it.
With upcoming kernel changes[1], the Linux kernel will reject QEMU's
request to adjust the guest's clock in this case, so don't attempt to set
the clock.
This avoids the following warning message on save/restore of a PV guest:
warning: Unable to set KVM guest TOD clock: Operation not supported
[1] https://lore.kernel.org/all/20221011160712.928239-2-nrb@linux.ibm.com/
Fixes: c3347ed0d2ee ("s390x: protvirt: Support unpack facility")
Signed-off-by: Nico Boehr <nrb@linux.ibm.com>
---
hw/s390x/tod-kvm.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/hw/s390x/tod-kvm.c b/hw/s390x/tod-kvm.c
index 9d0cbfbce2bf..303bd67ee64f 100644
--- a/hw/s390x/tod-kvm.c
+++ b/hw/s390x/tod-kvm.c
@@ -13,6 +13,7 @@
#include "qemu/module.h"
#include "sysemu/runstate.h"
#include "hw/s390x/tod.h"
+#include "hw/s390x/pv.h"
#include "kvm/kvm_s390x.h"
static void kvm_s390_get_tod_raw(S390TOD *tod, Error **errp)
@@ -84,6 +85,13 @@ static void kvm_s390_tod_vm_state_change(void *opaque, bool
running,
S390TODState *td = opaque;
Error *local_err = NULL;
+ /*
+ * Under PV, the clock is under ultravisor control, hence we cannot restore
+ * it on resume.
+ */
+ if (s390_is_pv())
+ return;