On Wed, 17 Jul 2019 15:39:52 +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
> ---
> 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 = >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;
> +}
> +
PAPR says that H_JOIN "performs the equivalent of a H_CONFER (proc=self)",
unless called by the last unjoined thread, in which case H_CONTINUE
should be returned. It thus seems that the spapr_cpu->prod check should
be done after the loop below otherwise if the last active thread was
just prodded (can happen?), it won't return the expected value, and...
> +CPU_FOREACH(cs) {
> +PowerPCCPU *c = POWERPC_CPU(cs);
> +CPUPPCState *e = >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;
... then, you can maybe factor out this code to an h_confer_self()
helper to be called by h_join() and h_confer() ?
> +}
> +
> 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 */
