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>
---
This has been tested with TCG with some Linux hacks to use H_JOIN/H_PROD
for suspend and CPU unplug (plus an implementation of ibm,suspend-me to
do the suspend). Not sure if KVM might need some more work to support
H_JOIN properly, but right now Linux only uses it on PowerVM.
hw/ppc/spapr_hcall.c | 84 ++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 84 insertions(+)
diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c
index 8a736797b9..6829cadcd3 100644
--- a/hw/ppc/spapr_hcall.c
+++ b/hw/ppc/spapr_hcall.c
@@ -1065,6 +1065,86 @@ 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 = CPU(cpu);
+
+ if (env->msr & (1ULL << MSR_EE))
+ return H_BAD_MODE;
+
+ /*
+ * This should check for single-threaded mode. In practice, Linux
+ * does not try to H_JOIN all CPUs.
+ */
+
+ 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)
+{
+ 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;
+
+ /*
+ * H_CONFER with target == this is not exactly the same as H_JOIN
+ * according to PAPR (e.g., MSR[EE] check and single threaded check
+ * is not done in this case), but unlikely to matter.
+ */
+ if (cpu == spapr_find_cpu(target))
+ return h_join(cpu, spapr, opcode, args);
+
+ /*
+ * 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;
+}
+
+/*
+ * H_PROD and H_CONFER are specified to only modify GPR r3, which is not
+ * achievable running under KVM, although KVM already implements H_CONFER
+ * this way.
+ */
+static target_ulong h_prod(PowerPCCPU *cpu, SpaprMachineState *spapr,
+ target_ulong opcode, target_ulong *args)
+{
+ target_long target = args[0];
+ CPUState *cs;
+
+ /*
+ * This does not maintain a prod flag for the vCPU that PAPR asks for.
+ */
+
+ 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 +1940,10 @@ 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_JOIN, h_join);
+ 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
