These implementations have a few deficiencies that are noted, but are good enough for Linux to use.
Signed-off-by: Nicholas Piggin <npig...@gmail.com> --- v3: Removed wrong comment about GPR3, drop H_JOIN for now (at least until it is tested some more in Linux/KVM), and expand the comment about not prod bit. hw/ppc/spapr_hcall.c | 71 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 71 insertions(+) diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c index 8a736797b9..8892ad008b 100644 --- a/hw/ppc/spapr_hcall.c +++ b/hw/ppc/spapr_hcall.c @@ -1065,6 +1065,74 @@ static target_ulong h_cede(PowerPCCPU *cpu, SpaprMachineState *spapr, return H_SUCCESS; } +static target_ulong h_confer(PowerPCCPU *cpu, SpaprMachineState *spapr, + target_ulong opcode, target_ulong *args) +{ + target_long target = args[0]; + CPUState *cs = CPU(cpu); + + /* + * This does not do a targeted yield or confer, but check the parameter + * anyway. -1 means confer to all/any other CPUs. + */ + if (target != -1 && !CPU(spapr_find_cpu(target))) { + return H_PARAMETER; + } + + /* + * PAPR calls for waiting until proded in this case (or presumably + * an external interrupt if MSR[EE]=1, without dispatch sequence count + * check. + */ + if (cpu == spapr_find_cpu(target)) { + cs->halted = 1; + cs->exception_index = EXCP_HALTED; + cs->exit_request = 1; + + return H_SUCCESS; + } + + /* + * This does not implement the dispatch sequence check that PAPR calls for, + * but PAPR also specifies a stronger implementation where the target must + * be run (or EE, or H_PROD) before H_CONFER returns. Without such a hard + * scheduling requirement implemented, there is no correctness reason to + * implement the dispatch sequence check. + */ + cs->exception_index = EXCP_YIELD; + cpu_loop_exit(cs); + + return H_SUCCESS; +} + +static target_ulong h_prod(PowerPCCPU *cpu, SpaprMachineState *spapr, + target_ulong opcode, target_ulong *args) +{ + target_long target = args[0]; + CPUState *cs; + + /* + * PAPR specifies there should be a prod flag should be associated with + * a vCPU, which gets set here, tested by H_CEDE, and cleared any time + * the vCPU is dispatched, including via preemption. + * + * We don't implement this because it is not used by Linux. The bit would + * be difficult or impossible to use properly because preemption can not + * be prevented so dispatch sequence count would have to somehow be used + * to detect it. + */ + + cs = CPU(spapr_find_cpu(target)); + if (!cs) { + return H_PARAMETER; + } + + cs->halted = 0; + qemu_cpu_kick(cs); + + return H_SUCCESS; +} + static target_ulong h_rtas(PowerPCCPU *cpu, SpaprMachineState *spapr, target_ulong opcode, target_ulong *args) { @@ -1860,6 +1928,9 @@ static void hypercall_register_types(void) /* hcall-splpar */ spapr_register_hypercall(H_REGISTER_VPA, h_register_vpa); spapr_register_hypercall(H_CEDE, h_cede); + spapr_register_hypercall(H_CONFER, h_confer); + spapr_register_hypercall(H_PROD, h_prod); + spapr_register_hypercall(H_SIGNAL_SYS_RESET, h_signal_sys_reset); /* processor register resource access h-calls */ -- 2.20.1