On Tue, Apr 16, 2019 at 02:55:52PM +1000, Nicholas Piggin wrote: > 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.
Is this comment complete? It's missing a closing parenthesis at the very least. > + */ > + 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. Hm. AFAIK the dispatch sequence count only exists with KVM, so I don't see how testing it would fit with a userspace implementation of PROD. > + */ > + > + 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); You're no longer enabling the KVM CONFER and PROD hypercalls. Are they enabled by default, or is that an intentional change? > /* 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
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