On Tue, Aug 24, 2021 at 01:30:26PM -0300, Daniel Henrique Barboza wrote: > From: Gustavo Romero > > Following up the rfebb implementation, this patch adds the EBB exception > support that are triggered by Performance Monitor alerts. This exception > occurs when an enabled PMU condition or event happens and both MMCR0_EBE > and BESCR_PME are set. > > The supported PM alerts will consist of counter negative conditions of > the PMU counters. This will be achieved by a timer mechanism that will > predict when a counter becomes negative. The PMU timer callback will set > the appropriate bits in MMCR0 and fire a PMC interrupt. The EBB > exception code will then set the appropriate BESCR bits, set the next > instruction pointer to the address pointed by the return register > (SPR_EBBRR), and redirect execution to the handler (pointed by > SPR_EBBHR). > > This patch sets the basic structure of interrupts and timers. The > following patches will add the counter negative logic for the > registers. A timer makes sense for tripping cycles based EBB events. But for instructions based EBB events, shouldn't you instead have a test in the update instructions path which trips the event if you've passed the magic number? > > CC: Gustavo Romero > Signed-off-by: Gustavo Romero > Signed-off-by: Daniel Henrique Barboza > --- > hw/ppc/spapr_cpu_core.c | 6 ++++++ > target/ppc/cpu.h | 12 +++++++++++- > target/ppc/excp_helper.c | 28 +++++++++++++++++++++++++++ > target/ppc/power8_pmu.c | 41 ++++++++++++++++++++++++++++++++++++++++ > target/ppc/power8_pmu.h | 25 ++++++++++++++++++++++++ > 5 files changed, 111 insertions(+), 1 deletion(-) > create mode 100644 target/ppc/power8_pmu.h > > diff --git a/hw/ppc/spapr_cpu_core.c b/hw/ppc/spapr_cpu_core.c > index 4f316a6f9d..c7a342c4aa 100644 > --- a/hw/ppc/spapr_cpu_core.c > +++ b/hw/ppc/spapr_cpu_core.c > @@ -20,6 +20,7 @@ > #include "target/ppc/kvm_ppc.h" > #include "hw/ppc/ppc.h" > #include "target/ppc/mmu-hash64.h" > +#include "target/ppc/power8_pmu.h" > #include "sysemu/numa.h" > #include "sysemu/reset.h" > #include "sysemu/hw_accel.h" > @@ -266,6 +267,11 @@ static bool spapr_realize_vcpu(PowerPCCPU *cpu, SpaprMachineState *spapr, > return false; > } > > + /* Init PMU interrupt timer (TCG only) */ > + if (!kvm_enabled()) { > + cpu_ppc_pmu_timer_init(env); > + } > + > if (!sc->pre_3_0_migration) { > vmstate_register(NULL, cs->cpu_index, &vmstate_spapr_cpu_state, > cpu->machine_data); > diff --git a/target/ppc/cpu.h b/target/ppc/cpu.h > index 9d5eb9ead4..535754ddff 100644 > --- a/target/ppc/cpu.h > +++ b/target/ppc/cpu.h > @@ -129,8 +129,9 @@ enum { > /* ISA 3.00 additions */ > POWERPC_EXCP_HVIRT = 101, > POWERPC_EXCP_SYSCALL_VECTORED = 102, /* scv exception */ > + POWERPC_EXCP_EBB = 103, /* Event-based branch exception */ > /* EOL */ > - POWERPC_EXCP_NB = 103, > + POWERPC_EXCP_NB = 104, > /* QEMU exceptions: special cases we want to stop translation */ > POWERPC_EXCP_SYSCALL_USER = 0x203, /* System call in user mode only */ > }; > @@ -1047,6 +1048,8 @@ struct ppc_radix_page_info { > #define PPC_CPU_OPCODES_LEN 0x40 > #define PPC_CPU_INDIRECT_OPCODES_LEN 0x20 > > +#define PMU_TIMERS_LEN 5 > + > struct CPUPPCState { > /* Most commonly used resources during translated code execution first */ > target_ulong gpr[32]; /* general purpose registers */ > @@ -1208,6 +1211,12 @@ struct CPUPPCState { > * running cycles. > */ > uint64_t pmu_base_time; > + > + /* > + * Timers used to fire performance monitor alerts and > + * interrupts. All PMCs but PMC5 has a timer. > + */ > + QEMUTimer *pmu_intr_timers[PMU_TIMERS_LEN]; > }; > > #define SET_FIT_PERIOD(a_, b_, c_, d_) \ > @@ -2424,6 +2433,7 @@ enum { > PPC_INTERRUPT_HMI, /* Hypervisor Maintenance interrupt */ > PPC_INTERRUPT_HDOORBELL, /* Hypervisor Doorbell interrupt */ > PPC_INTERRUPT_HVIRT, /* Hypervisor virtualization interrupt */ > + PPC_INTERRUPT_PMC, /* Performance Monitor Counter interrupt */ > }; > > /* Processor Compatibility mask (PCR) */ > diff --git a/target/ppc/excp_helper.c b/target/ppc/excp_helper.c > index 058b063d8a..e97898c5f4 100644 > --- a/target/ppc/excp_helper.c > +++ b/target/ppc/excp_helper.c > @@ -821,6 +821,22 @@ static inline void powerpc_excp(PowerPCCPU *cpu, int excp_model, int excp) > cpu_abort(cs, "Non maskable external exception " > "is not implemented yet !\n"); > break; > + case POWERPC_EXCP_EBB: /* Event-based branch exception */ > + if ((env->spr[SPR_BESCR] & BESCR_GE) && > + (env->spr[SPR_BESCR] & BESCR_PME)) { > + target_ulong nip; > + > + env->spr[SPR_BESCR] &= ~BESCR_GE; /* Clear GE */ > + env->spr[SPR_BESCR] |= BESCR_PMEO; /* Set PMEO */ > + env->spr[SPR_EBBRR] = env->nip; /* Save NIP for rfebb insn */ > + nip = env->spr[SPR_EBBHR]; /* EBB handler */ > + powerpc_set_excp_state(cpu, nip, env->msr); > + } > + /* > + * This interrupt is handled by userspace. No need > + * to proceed. > + */ > + return; > default: > excp_invalid: > cpu_abort(cs, "Invalid PowerPC exception %d. Aborting\n", excp); > @@ -1068,6 +1084,18 @@ static void ppc_hw_interrupt(CPUPPCState *env) > powerpc_excp(cpu, env->excp_model, POWERPC_EXCP_THERM); > return; > } > + /* PMC -> Event-based branch exception */ > + if (env->pending_interrupts & (1 << PPC_INTERRUPT_PMC)) { > + /* > + * Performance Monitor event-based exception can only > + * occur in problem state. > + */ > + if (msr_pr == 1) { > + env->pending_interrupts &= ~(1 << PPC_INTERRUPT_PMC); > + powerpc_excp(cpu, env->excp_model, POWERPC_EXCP_EBB); > + return; > + } > + } > } > > if (env->resume_as_sreset) { > diff --git a/target/ppc/power8_pmu.c b/target/ppc/power8_pmu.c > index 4545fe7810..a57b602125 100644 > --- a/target/ppc/power8_pmu.c > +++ b/target/ppc/power8_pmu.c > @@ -12,12 +12,14 @@ > > #include "qemu/osdep.h" > > +#include "power8_pmu.h" > #include "cpu.h" > #include "helper_regs.h" > #include "exec/exec-all.h" > #include "exec/helper-proto.h" > #include "qemu/error-report.h" > #include "qemu/main-loop.h" > +#include "hw/ppc/ppc.h" > > #if defined(TARGET_PPC64) && !defined(CONFIG_USER_ONLY) > > @@ -114,6 +116,45 @@ static void update_cycles_PMCs(CPUPPCState *env) > } > } > > +static void cpu_ppc_pmu_timer_cb(void *opaque) > +{ > + PowerPCCPU *cpu = opaque; > + CPUPPCState *env = &cpu->env; > + uint64_t mmcr0; > + > + mmcr0 = env->spr[SPR_POWER_MMCR0]; > + if (env->spr[SPR_POWER_MMCR0] & MMCR0_EBE) { > + /* freeeze counters if needed */ > + if (mmcr0 & MMCR0_FCECE) { > + mmcr0 &= ~MMCR0_FCECE; > + mmcr0 |= MMCR0_FC; > + } > + > + /* Clear PMAE and set PMAO */ > + if (mmcr0 & MMCR0_PMAE) { > + mmcr0 &= ~MMCR0_PMAE; > + mmcr0 |= MMCR0_PMAO; > + } > + env->spr[SPR_POWER_MMCR0] = mmcr0; > + > + /* Fire the PMC hardware exception */ > + ppc_set_irq(cpu, PPC_INTERRUPT_PMC, 1); > + } > +} > + > +void cpu_ppc_pmu_timer_init(CPUPPCState *env) > +{ > + PowerPCCPU *cpu = env_archcpu(env); > + QEMUTimer *timer; > + int i; > + > + for (i = 0; i < PMU_TIMERS_LEN; i++) { > + timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, &cpu_ppc_pmu_timer_cb, > + cpu); > + env->pmu_intr_timers[i] = timer; > + } > +} > + > void helper_store_mmcr0(CPUPPCState *env, target_ulong value) > { > target_ulong curr_value = env->spr[SPR_POWER_MMCR0]; > diff --git a/target/ppc/power8_pmu.h b/target/ppc/power8_pmu.h > new file mode 100644 > index 0000000000..34a9d0e8a2 > --- /dev/null > +++ b/target/ppc/power8_pmu.h > @@ -0,0 +1,25 @@ > +/* > + * PMU emulation helpers for TCG IBM POWER chips > + * > + * Copyright IBM Corp. 2021 > + * > + * Authors: > + * Daniel Henrique Barboza > + * > + * This work is licensed under the terms of the GNU GPL, version 2 or later. > + * See the COPYING file in the top-level directory. > + */ > + > +#ifndef PMU_BOOK3S_HELPER > +#define PMU_BOOK3S_HELPER > + > +#include "qemu/osdep.h" > +#include "cpu.h" > +#include "exec/exec-all.h" > +#include "exec/helper-proto.h" > +#include "qemu/error-report.h" > +#include "qemu/main-loop.h" > + > +void cpu_ppc_pmu_timer_init(CPUPPCState *env); > + > +#endif -- 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