spapr: Enable in-kernel H_SET_MODE handling

For setting debug watchpoints, sPAPR guests use H_SET_MODE hypercall.
The existing QEMU H_SET_MODE handler does not support this but
the KVM handler in HV KVM does. However it is not enabled.

This enables the in-kernel H_SET_MODE handler which handles:
- Completed Instruction Address Breakpoint Register
- Watch point 0 registers.

The rest is still handled in QEMU.

Reported-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

hw/ppc/spapr.c

@@ -1546,6 +1546,7 @@ static void ppc_spapr_init(MachineState *machine)
     if (kvm_enabled()) {
         /* Enable H_LOGICAL_CI_* so SLOF can talk to in-kernel devices */
         kvmppc_enable_logical_ci_hcalls();
+        kvmppc_enable_set_mode_hcall();
     }
 
     /* allocate RAM */

target-ppc/kvm.c

@@ -1953,6 +1953,11 @@ void kvmppc_enable_logical_ci_hcalls(void)
     kvmppc_enable_hcall(kvm_state, H_LOGICAL_CI_STORE);
 }
 
+void kvmppc_enable_set_mode_hcall(void)
+{
+    kvmppc_enable_hcall(kvm_state, H_SET_MODE);
+}
+
 void kvmppc_set_papr(PowerPCCPU *cpu)
 {
     CPUState *cs = CPU(cpu);

target-ppc/kvm_ppc.h

@@ -23,6 +23,7 @@ int kvmppc_get_hasidle(CPUPPCState *env);
 int kvmppc_get_hypercall(CPUPPCState *env, uint8_t *buf, int buf_len);
 int kvmppc_set_interrupt(PowerPCCPU *cpu, int irq, int level);
 void kvmppc_enable_logical_ci_hcalls(void);
+void kvmppc_enable_set_mode_hcall(void);
 void kvmppc_set_papr(PowerPCCPU *cpu);
 int kvmppc_set_compat(PowerPCCPU *cpu, uint32_t cpu_version);
 void kvmppc_set_mpic_proxy(PowerPCCPU *cpu, int mpic_proxy);
@@ -110,6 +111,10 @@ static inline void kvmppc_enable_logical_ci_hcalls(void)
 {
 }
 
+static inline void kvmppc_enable_set_mode_hcall(void)
+{
+}
+
 static inline void kvmppc_set_papr(PowerPCCPU *cpu)
 {
 }