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 <npiggin@gmail.com>
---
 hw/ppc/spapr.c       |  1 +
 hw/ppc/spapr_hcall.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 45 insertions(+)

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 87b11e2484..5c54e1cb9a 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 28d58113be..52847a7047 100644
--- a/hw/ppc/spapr_hcall.c
+++ b/hw/ppc/spapr_hcall.c
@@ -1069,6 +1069,47 @@ 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)
 {
@@ -1959,6 +2000,9 @@ 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

On Tue, Jul 16, 2019 at 12:47:25PM +1000, Nicholas Piggin wrote:
> 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 <npiggin@gmail.com>

LGTM apart from style issues as noted by the bot.

> ---
>  hw/ppc/spapr.c       |  1 +
>  hw/ppc/spapr_hcall.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 45 insertions(+)
> 
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index 87b11e2484..5c54e1cb9a 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 28d58113be..52847a7047 100644
> --- a/hw/ppc/spapr_hcall.c
> +++ b/hw/ppc/spapr_hcall.c
> @@ -1069,6 +1069,47 @@ 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)
>  {
> @@ -1959,6 +2000,9 @@ 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 */

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson