[Qemu-devel] [PATCH v5 4/4] spapr: Implement H_JOIN

[Nicholas Piggin]

This has been useful to modify and test the Linux pseries suspend
code but it requires modification to the guest to call it (due to
being gated by other unimplemented features). It is not otherwise
used by Linux yet, but work is slowly progressing there.

Signed-off-by: Nicholas Piggin <address@hidden>
---
Changes since v4:
- Style

 hw/ppc/spapr.c       |  1 +
 hw/ppc/spapr_hcall.c | 45 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 46 insertions(+)

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 13c423347e..59cd24f9c3 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -1066,6 +1066,7 @@ static void spapr_dt_rtas(SpaprMachineState *spapr, void 
*fdt)
     add_str(hypertas, "hcall-tce");
     add_str(hypertas, "hcall-vio");
     add_str(hypertas, "hcall-splpar");
+    add_str(hypertas, "hcall-join");
     add_str(hypertas, "hcall-bulk");
     add_str(hypertas, "hcall-set-mode");
     add_str(hypertas, "hcall-sprg0");
diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c
index 5e655172b2..57c1ee0fe1 100644
--- a/hw/ppc/spapr_hcall.c
+++ b/hw/ppc/spapr_hcall.c
@@ -1069,6 +1069,48 @@ static target_ulong h_cede(PowerPCCPU *cpu, 
SpaprMachineState *spapr,
     return H_SUCCESS;
 }
 
+static target_ulong h_join(PowerPCCPU *cpu, SpaprMachineState *spapr,
+                           target_ulong opcode, target_ulong *args)
+{
+    CPUPPCState *env = &cpu->env;
+    CPUState *cs;
+    SpaprCpuState *spapr_cpu = spapr_cpu_state(cpu);
+    bool last_unjoined = true;
+
+    if (env->msr & (1ULL << MSR_EE)) {
+        return H_BAD_MODE;
+    }
+
+    if (spapr_cpu->prod) {
+        spapr_cpu->prod = false;
+        return H_SUCCESS;
+    }
+
+    CPU_FOREACH(cs) {
+        PowerPCCPU *c = POWERPC_CPU(cs);
+        CPUPPCState *e = &c->env;
+        if (c == cpu) {
+            continue;
+        }
+
+        /* Don't have a way to indicate joined, so use halted && MSR[EE]=0 */
+        if (!cs->halted || (e->msr & (1ULL << MSR_EE))) {
+            last_unjoined = false;
+            break;
+        }
+    }
+    if (last_unjoined) {
+        return H_CONTINUE;
+    }
+
+    cs = CPU(cpu);
+    cs->halted = 1;
+    cs->exception_index = EXCP_HALTED;
+    cs->exit_request = 1;
+
+    return H_SUCCESS;
+}
+
 static target_ulong h_confer(PowerPCCPU *cpu, SpaprMachineState *spapr,
                            target_ulong opcode, target_ulong *args)
 {
@@ -1979,6 +2021,9 @@ static void hypercall_register_types(void)
     spapr_register_hypercall(H_CONFER, h_confer);
     spapr_register_hypercall(H_PROD, h_prod);
 
+    /* hcall-join */
+    spapr_register_hypercall(H_JOIN, h_join);
+
     spapr_register_hypercall(H_SIGNAL_SYS_RESET, h_signal_sys_reset);
 
     /* processor register resource access h-calls */
-- 
2.20.1