If KVM is too old to support XIVE native exploitation mode, we might end
up using the emulated XIVE after CAS. This is sub-optimal if KVM in-kernel
XICS is available, which is the case most of the time.
Also, an old KVM may not allow to destroy and re-create the KVM XICS, which
is precisely what "dual" does during machine reset. This causes QEMU to try
to switch to emulated XICS and to crash because RTAS call de-registration
isn't handled correctly. We could possibly fix that, but again we would
still end up with an emulated XICS or XIVE.
"dual" is definitely not a good choice with older KVMs. Internally force
XICS when we detect this.
Signed-off-by: Greg Kurz <gr...@kaod.org>
---
hw/ppc/spapr_irq.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/hw/ppc/spapr_irq.c b/hw/ppc/spapr_irq.c
index 3156daf09381..d788bd662a7a 100644
--- a/hw/ppc/spapr_irq.c
+++ b/hw/ppc/spapr_irq.c
@@ -18,6 +18,7 @@
#include "hw/ppc/xics_spapr.h"
#include "cpu-models.h"
#include "sysemu/kvm.h"
+#include "kvm_ppc.h"
#include "trace.h"
@@ -668,6 +669,15 @@ static void spapr_irq_check(SpaprMachineState *spapr,
Error **errp)
return;
}
}
+
+ /*
+ * KVM may be too old to support XIVE, in which case we'd rather try
+ * to use the in-kernel XICS instead of the emulated XIVE.
+ */
+ if (kvm_enabled() && !kvmppc_has_cap_xive() &&
+ spapr->irq == &spapr_irq_dual) {
+ spapr->irq = &spapr_irq_xics;
+ }
}
/*
