[PATCH v12 0/5] PMU-EBB support for PPC64 TCG

[PATCH v12 0/5] PMU-EBB support for PPC64 TCG

[Daniel Henrique Barboza]

Hi,

This new version adds a new patch (patch 2) that fixes --disable-tcg
--disable-linux-user compilation.

The series was based on upstream master.

Changes from v12:
- patch 2 (new):
  * make power8-pmu.c compile only with CONFIG_TCG available
- patch 4 (former 3):
  * added Cedric's r-b
- v11 link: https://lists.gnu.org/archive/html/qemu-devel/2022-02/msg02693.html

Daniel Henrique Barboza (5):
  target/ppc: fix indent of powerpc_set_excp_state()
  target/ppc: make power8-pmu.c CONFIG_TCG only
  target/ppc: finalize pre-EBB PMU logic
  target/ppc: add PPC_INTERRUPT_EBB and EBB exceptions
  target/ppc: trigger PERFM EBBs from power8-pmu.c

 target/ppc/cpu.h         |  5 ++-
 target/ppc/cpu_init.c    |  9 +++--
 target/ppc/excp_helper.c | 83 +++++++++++++++++++++++++++++++++++++++-
 target/ppc/helper.h      |  1 +
 target/ppc/machine.c     |  2 +
 target/ppc/meson.build   |  2 +-
 target/ppc/power8-pmu.c  | 39 +++++++++++++++++--
 target/ppc/power8-pmu.h  |  4 +-
 8 files changed, 133 insertions(+), 12 deletions(-)

-- 
2.34.1

[PATCH v12 1/5] target/ppc: fix indent of powerpc_set_excp_state()

[Daniel Henrique Barboza]

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
---
 target/ppc/excp_helper.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/target/ppc/excp_helper.c b/target/ppc/excp_helper.c
index fcc83a7701..bbc75afbc0 100644
--- a/target/ppc/excp_helper.c
+++ b/target/ppc/excp_helper.c
@@ -361,7 +361,7 @@ static void ppc_excp_apply_ail(PowerPCCPU *cpu, int excp, target_ulong msr,
 #endif
 
 static void powerpc_set_excp_state(PowerPCCPU *cpu,
-                                          target_ulong vector, target_ulong msr)
+                                   target_ulong vector, target_ulong msr)
 {
     CPUState *cs = CPU(cpu);
     CPUPPCState *env = &cpu->env;
-- 
2.34.1

[PATCH v12 2/5] target/ppc: make power8-pmu.c CONFIG_TCG only

[Daniel Henrique Barboza]

This is an exclusive TCG helper. Gating it with CONFIG_TCG and changing
meson.build accordingly will prevent problems --disable-tcg and
--disable-linux-user later on.

Suggested-by: Fabiano Rosas <farosas@linux.ibm.com>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
---
 target/ppc/cpu_init.c   | 5 ++---
 target/ppc/machine.c    | 2 ++
 target/ppc/meson.build  | 2 +-
 target/ppc/power8-pmu.h | 4 ++--
 4 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/target/ppc/cpu_init.c b/target/ppc/cpu_init.c
index d97f718354..8fc644f8d6 100644
--- a/target/ppc/cpu_init.c
+++ b/target/ppc/cpu_init.c
@@ -6379,7 +6379,7 @@ static void register_power9_mmu_sprs(CPUPPCState *env)
  */
 static void init_tcg_pmu_power8(CPUPPCState *env)
 {
-#if defined(TARGET_PPC64) && !defined(CONFIG_USER_ONLY)
+#if defined(CONFIG_TCG)
     /* Init PMU overflow timers */
     if (!kvm_enabled()) {
         cpu_ppc_pmu_init(env);
@@ -7872,10 +7872,9 @@ static void ppc_cpu_reset(DeviceState *dev)
     if (env->mmu_model != POWERPC_MMU_REAL) {
         ppc_tlb_invalidate_all(env);
     }
+    pmu_update_summaries(env);
 #endif /* CONFIG_TCG */
 #endif
-
-    pmu_update_summaries(env);
     hreg_compute_hflags(env);
     env->reserve_addr = (target_ulong)-1ULL;
     /* Be sure no exception or interrupt is pending */
diff --git a/target/ppc/machine.c b/target/ppc/machine.c
index 1b63146ed1..a4b0fa1a78 100644
--- a/target/ppc/machine.c
+++ b/target/ppc/machine.c
@@ -20,7 +20,9 @@ static void post_load_update_msr(CPUPPCState *env)
      */
     env->msr ^= env->msr_mask & ~((1ULL << MSR_TGPR) | MSR_HVB);
     ppc_store_msr(env, msr);
+#if defined(CONFIG_TCG)
     pmu_update_summaries(env);
+#endif
 }
 
 static int get_avr(QEMUFile *f, void *pv, size_t size,
diff --git a/target/ppc/meson.build b/target/ppc/meson.build
index a49a8911e0..79beaff147 100644
--- a/target/ppc/meson.build
+++ b/target/ppc/meson.build
@@ -16,6 +16,7 @@ ppc_ss.add(when: 'CONFIG_TCG', if_true: files(
   'misc_helper.c',
   'timebase_helper.c',
   'translate.c',
+  'power8-pmu.c',
 ))
 
 ppc_ss.add(libdecnumber)
@@ -51,7 +52,6 @@ ppc_softmmu_ss.add(when: 'TARGET_PPC64', if_true: files(
   'mmu-book3s-v3.c',
   'mmu-hash64.c',
   'mmu-radix64.c',
-  'power8-pmu.c',
 ))
 
 target_arch += {'ppc': ppc_ss}
diff --git a/target/ppc/power8-pmu.h b/target/ppc/power8-pmu.h
index a839199561..256d90f523 100644
--- a/target/ppc/power8-pmu.h
+++ b/target/ppc/power8-pmu.h
@@ -13,11 +13,11 @@
 #ifndef POWER8_PMU
 #define POWER8_PMU
 
-void cpu_ppc_pmu_init(CPUPPCState *env);
-
 #if defined(TARGET_PPC64) && !defined(CONFIG_USER_ONLY)
+void cpu_ppc_pmu_init(CPUPPCState *env);
 void pmu_update_summaries(CPUPPCState *env);
 #else
+static inline void cpu_ppc_pmu_init(CPUPPCState *env) { }
 static inline void pmu_update_summaries(CPUPPCState *env) { }
 #endif
 
-- 
2.34.1

Re: [PATCH v12 2/5] target/ppc: make power8-pmu.c CONFIG_TCG only

[Richard Henderson]

On 2/16/22 21:10, Daniel Henrique Barboza wrote:
>   static void init_tcg_pmu_power8(CPUPPCState *env)
>   {
> -#if defined(TARGET_PPC64) && !defined(CONFIG_USER_ONLY)
> +#if defined(CONFIG_TCG)
>       /* Init PMU overflow timers */
>       if (!kvm_enabled()) {
>           cpu_ppc_pmu_init(env);
> @@ -7872,10 +7872,9 @@ static void ppc_cpu_reset(DeviceState *dev)
>       if (env->mmu_model != POWERPC_MMU_REAL) {
>           ppc_tlb_invalidate_all(env);
>       }
> +    pmu_update_summaries(env);
>   #endif /* CONFIG_TCG */
>   #endif
> -
> -    pmu_update_summaries(env);

It looks like you could remove all of the ifdefs if you simply use tcg_enabled() rather 
than !kvm_enabled().  If !defined(CONFIG_TCG), tcg_enabled() will be constant false, and 
the block will be optimized away.


r~

Re: [PATCH v12 2/5] target/ppc: make power8-pmu.c CONFIG_TCG only

[Daniel Henrique Barboza]

On 2/17/22 19:17, Richard Henderson wrote:
> On 2/16/22 21:10, Daniel Henrique Barboza wrote:
>>   static void init_tcg_pmu_power8(CPUPPCState *env)
>>   {
>> -#if defined(TARGET_PPC64) && !defined(CONFIG_USER_ONLY)
>> +#if defined(CONFIG_TCG)
>>       /* Init PMU overflow timers */
>>       if (!kvm_enabled()) {
>>           cpu_ppc_pmu_init(env);
>> @@ -7872,10 +7872,9 @@ static void ppc_cpu_reset(DeviceState *dev)
>>       if (env->mmu_model != POWERPC_MMU_REAL) {
>>           ppc_tlb_invalidate_all(env);
>>       }
>> +    pmu_update_summaries(env);
>>   #endif /* CONFIG_TCG */
>>   #endif
>> -
>> -    pmu_update_summaries(env);
> 
> It looks like you could remove all of the ifdefs if you simply use tcg_enabled() rather than !kvm_enabled().  If !defined(CONFIG_TCG), tcg_enabled() will be constant false, and the block will be optimized away.


Just tested and it works. Thanks for the tip.

I'll re-send with this change.


Thanks,


Daniel

> 
> 
> r~

[PATCH v12 3/5] target/ppc: finalize pre-EBB PMU logic

[Daniel Henrique Barboza]

There are still PMU exclusive bits to handle in fire_PMC_interrupt()
before implementing the EBB support. Let's finalize it now to avoid
dealing with PMU and EBB logic at the same time in the next patches.

fire_PMC_interrupt() will fire an Performance Monitor alert depending on
MMCR0_PMAE. If we are required to freeze the timers (MMCR0_FCECE) we'll
also need to update summaries and delete the existing overflow timers.
In all cases we're going to update the cycle counters.

Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
---
 target/ppc/power8-pmu.c | 36 ++++++++++++++++++++++++++++++++++--
 1 file changed, 34 insertions(+), 2 deletions(-)

diff --git a/target/ppc/power8-pmu.c b/target/ppc/power8-pmu.c
index 236e8e66e9..d245663158 100644
--- a/target/ppc/power8-pmu.c
+++ b/target/ppc/power8-pmu.c
@@ -222,6 +222,20 @@ static void pmu_update_overflow_timers(CPUPPCState *env)
     }
 }
 
+static void pmu_delete_timers(CPUPPCState *env)
+{
+    QEMUTimer *pmc_overflow_timer;
+    int sprn;
+
+    for (sprn = SPR_POWER_PMC1; sprn <= SPR_POWER_PMC6; sprn++) {
+        pmc_overflow_timer = get_cyc_overflow_timer(env, sprn);
+
+        if (pmc_overflow_timer) {
+            timer_del(pmc_overflow_timer);
+        }
+    }
+}
+
 void helper_store_mmcr0(CPUPPCState *env, target_ulong value)
 {
     bool hflags_pmcc0 = (value & MMCR0_PMCC0) != 0;
@@ -271,8 +285,26 @@ static void fire_PMC_interrupt(PowerPCCPU *cpu)
 {
     CPUPPCState *env = &cpu->env;
 
-    if (!(env->spr[SPR_POWER_MMCR0] & MMCR0_EBE)) {
-        return;
+    pmu_update_cycles(env);
+
+    if (env->spr[SPR_POWER_MMCR0] & MMCR0_FCECE) {
+        env->spr[SPR_POWER_MMCR0] &= ~MMCR0_FCECE;
+        env->spr[SPR_POWER_MMCR0] |= MMCR0_FC;
+
+        /* Changing MMCR0_FC requires a new HFLAGS_INSN_CNT calc */
+        pmu_update_summaries(env);
+
+        /*
+         * Delete all pending timers if we need to freeze
+         * the PMC. We'll restart them when the PMC starts
+         * running again.
+         */
+        pmu_delete_timers(env);
+    }
+
+    if (env->spr[SPR_POWER_MMCR0] & MMCR0_PMAE) {
+        env->spr[SPR_POWER_MMCR0] &= ~MMCR0_PMAE;
+        env->spr[SPR_POWER_MMCR0] |= MMCR0_PMAO;
     }
 
     /* PMC interrupt not implemented yet */
-- 
2.34.1

[PATCH v12 4/5] target/ppc: add PPC_INTERRUPT_EBB and EBB exceptions

[Daniel Henrique Barboza]

PPC_INTERRUPT_EBB is a new interrupt that will be used to deliver EBB
exceptions that had to be postponed because the thread wasn't in problem
state at the time the event-based branch was supposed to occur.

ISA 3.1 also defines two EBB exceptions: Performance Monitor EBB
exception and External EBB exception. They are being added as
POWERPC_EXCP_PERFM_EBB and POWERPC_EXCP_EXTERNAL_EBB.

PPC_INTERRUPT_EBB will check BESCR bits to see the EBB type that
occurred and trigger the appropriate exception. Both exceptions are
doing the same thing in this first implementation: clear BESCR_GE and
enter the branch with env->nip retrieved from SPR_EBBHR.

The checks being done by the interrupt code are msr_pr and BESCR_GE
states. All other checks (EBB facility check, BESCR_PME bit, specific
bits related to the event type) must be done beforehand.

Reviewed-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
---
 target/ppc/cpu.h         |  5 ++++-
 target/ppc/cpu_init.c    |  4 ++++
 target/ppc/excp_helper.c | 33 +++++++++++++++++++++++++++++++++
 3 files changed, 41 insertions(+), 1 deletion(-)

diff --git a/target/ppc/cpu.h b/target/ppc/cpu.h
index 555c6b9245..e8a423d14d 100644
--- a/target/ppc/cpu.h
+++ b/target/ppc/cpu.h
@@ -127,8 +127,10 @@ enum {
     /* ISA 3.00 additions */
     POWERPC_EXCP_HVIRT    = 101,
     POWERPC_EXCP_SYSCALL_VECTORED = 102, /* scv exception                     */
+    POWERPC_EXCP_PERFM_EBB = 103,    /* Performance Monitor EBB Exception    */
+    POWERPC_EXCP_EXTERNAL_EBB = 104, /* External EBB Exception               */
     /* EOL                                                                   */
-    POWERPC_EXCP_NB       = 103,
+    POWERPC_EXCP_NB       = 105,
     /* QEMU exceptions: special cases we want to stop translation            */
     POWERPC_EXCP_SYSCALL_USER = 0x203, /* System call in user mode only      */
 };
@@ -2426,6 +2428,7 @@ enum {
     PPC_INTERRUPT_HMI,            /* Hypervisor Maintenance interrupt    */
     PPC_INTERRUPT_HDOORBELL,      /* Hypervisor Doorbell interrupt        */
     PPC_INTERRUPT_HVIRT,          /* Hypervisor virtualization interrupt  */
+    PPC_INTERRUPT_EBB,            /* Event-based Branch exception         */
 };
 
 /* Processor Compatibility mask (PCR) */
diff --git a/target/ppc/cpu_init.c b/target/ppc/cpu_init.c
index 8fc644f8d6..8ddac4e2fe 100644
--- a/target/ppc/cpu_init.c
+++ b/target/ppc/cpu_init.c
@@ -2239,6 +2239,10 @@ static void init_excp_POWER8(CPUPPCState *env)
     env->excp_vectors[POWERPC_EXCP_FU]       = 0x00000F60;
     env->excp_vectors[POWERPC_EXCP_HV_FU]    = 0x00000F80;
     env->excp_vectors[POWERPC_EXCP_SDOOR_HV] = 0x00000E80;
+
+    /* Userland exceptions without vector value in PowerISA v3.1 */
+    env->excp_vectors[POWERPC_EXCP_PERFM_EBB] = 0x0;
+    env->excp_vectors[POWERPC_EXCP_EXTERNAL_EBB] = 0x0;
 #endif
 }
 
diff --git a/target/ppc/excp_helper.c b/target/ppc/excp_helper.c
index bbc75afbc0..04c61cff39 100644
--- a/target/ppc/excp_helper.c
+++ b/target/ppc/excp_helper.c
@@ -1513,6 +1513,21 @@ static void powerpc_excp_books(PowerPCCPU *cpu, int excp)
         new_msr |= (target_ulong)MSR_HVB;
         new_msr |= env->msr & ((target_ulong)1 << MSR_RI);
         break;
+    case POWERPC_EXCP_PERFM_EBB:        /* Performance Monitor EBB Exception  */
+    case POWERPC_EXCP_EXTERNAL_EBB:     /* External EBB Exception             */
+        env->spr[SPR_BESCR] &= ~BESCR_GE;
+
+        /*
+         * Save NIP for rfebb insn in SPR_EBBRR. Next nip is
+         * stored in the EBB Handler SPR_EBBHR.
+         */
+        env->spr[SPR_EBBRR] = env->nip;
+        powerpc_set_excp_state(cpu, env->spr[SPR_EBBHR], env->msr);
+
+        /*
+         * This exception is handled in userspace. No need to proceed.
+         */
+        return;
     case POWERPC_EXCP_THERM:     /* Thermal interrupt                        */
     case POWERPC_EXCP_PERFM:     /* Embedded performance monitor interrupt   */
     case POWERPC_EXCP_VPUA:      /* Vector assist exception                  */
@@ -1742,6 +1757,24 @@ static void ppc_hw_interrupt(CPUPPCState *env)
             powerpc_excp(cpu, POWERPC_EXCP_THERM);
             return;
         }
+        /* EBB exception */
+        if (env->pending_interrupts & (1 << PPC_INTERRUPT_EBB)) {
+            /*
+             * EBB exception must be taken in problem state and
+             * with BESCR_GE set.
+             */
+            if (msr_pr == 1 && env->spr[SPR_BESCR] & BESCR_GE) {
+                env->pending_interrupts &= ~(1 << PPC_INTERRUPT_EBB);
+
+                if (env->spr[SPR_BESCR] & BESCR_PMEO) {
+                    powerpc_excp(cpu, POWERPC_EXCP_PERFM_EBB);
+                } else if (env->spr[SPR_BESCR] & BESCR_EEO) {
+                    powerpc_excp(cpu, POWERPC_EXCP_EXTERNAL_EBB);
+                }
+
+                return;
+            }
+        }
     }
 
     if (env->resume_as_sreset) {
-- 
2.34.1

[PATCH v12 5/5] target/ppc: trigger PERFM EBBs from power8-pmu.c

[Daniel Henrique Barboza]

This patch adds the EBB exception support that are triggered by
Performance Monitor alerts. This happens when a Performance Monitor
alert occurs and MMCR0_EBE, BESCR_PME and BESCR_GE are set.

fire_PMC_interrupt() will execute a new ebb_perfm_excp() helper that
will check for MMCR0_EBE, BESCR_PME and BESCR_GE bits. If all bits are
set, do_ebb() will attempt to trigger a PERFM EBB event.

If the EBB facility is enabled in both FSCR and HFSCR we consider that
the EBB is valid and set BESCR_PMEO. After that, if we're running in
problem state, fire a POWERPC_EXCP_PERM_EBB immediately. Otherwise we'll
queue a PPC_INTERRUPT_EBB.

Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
---
 target/ppc/excp_helper.c | 48 ++++++++++++++++++++++++++++++++++++++++
 target/ppc/helper.h      |  1 +
 target/ppc/power8-pmu.c  |  3 +--
 3 files changed, 50 insertions(+), 2 deletions(-)

diff --git a/target/ppc/excp_helper.c b/target/ppc/excp_helper.c
index 04c61cff39..32a28ecce2 100644
--- a/target/ppc/excp_helper.c
+++ b/target/ppc/excp_helper.c
@@ -2009,6 +2009,54 @@ void helper_rfebb(CPUPPCState *env, target_ulong s)
         env->spr[SPR_BESCR] &= ~BESCR_GE;
     }
 }
+
+/*
+ * Triggers or queues an 'ebb_excp' EBB exception. All checks
+ * but FSCR, HFSCR and msr_pr must be done beforehand.
+ *
+ * PowerISA v3.1 isn't clear about whether an EBB should be
+ * postponed or cancelled if the EBB facility is unavailable.
+ * Our assumption here is that the EBB is cancelled if both
+ * FSCR and HFSCR EBB facilities aren't available.
+ */
+static void do_ebb(CPUPPCState *env, int ebb_excp)
+{
+    PowerPCCPU *cpu = env_archcpu(env);
+    CPUState *cs = CPU(cpu);
+
+    /*
+     * FSCR_EBB and FSCR_IC_EBB are the same bits used with
+     * HFSCR.
+     */
+    helper_fscr_facility_check(env, FSCR_EBB, 0, FSCR_IC_EBB);
+    helper_hfscr_facility_check(env, FSCR_EBB, "EBB", FSCR_IC_EBB);
+
+    if (ebb_excp == POWERPC_EXCP_PERFM_EBB) {
+        env->spr[SPR_BESCR] |= BESCR_PMEO;
+    } else if (ebb_excp == POWERPC_EXCP_EXTERNAL_EBB) {
+        env->spr[SPR_BESCR] |= BESCR_EEO;
+    }
+
+    if (msr_pr == 1) {
+        powerpc_excp(cpu, ebb_excp);
+    } else {
+        env->pending_interrupts |= 1 << PPC_INTERRUPT_EBB;
+        cpu_interrupt(cs, CPU_INTERRUPT_HARD);
+    }
+}
+
+void helper_ebb_perfm_excp(CPUPPCState *env)
+{
+    bool perfm_ebb_enabled = env->spr[SPR_POWER_MMCR0] & MMCR0_EBE &&
+                             env->spr[SPR_BESCR] & BESCR_PME &&
+                             env->spr[SPR_BESCR] & BESCR_GE;
+
+    if (!perfm_ebb_enabled) {
+        return;
+    }
+
+    do_ebb(env, POWERPC_EXCP_PERFM_EBB);
+}
 #endif
 
 /*****************************************************************************/
diff --git a/target/ppc/helper.h b/target/ppc/helper.h
index ab008c9d4e..8c2c03fd48 100644
--- a/target/ppc/helper.h
+++ b/target/ppc/helper.h
@@ -18,6 +18,7 @@ DEF_HELPER_1(rfid, void, env)
 DEF_HELPER_1(rfscv, void, env)
 DEF_HELPER_1(hrfid, void, env)
 DEF_HELPER_2(rfebb, void, env, tl)
+DEF_HELPER_1(ebb_perfm_excp, void, env)
 DEF_HELPER_2(store_lpcr, void, env, tl)
 DEF_HELPER_2(store_pcr, void, env, tl)
 DEF_HELPER_2(store_mmcr0, void, env, tl)
diff --git a/target/ppc/power8-pmu.c b/target/ppc/power8-pmu.c
index d245663158..38e1ecb782 100644
--- a/target/ppc/power8-pmu.c
+++ b/target/ppc/power8-pmu.c
@@ -307,8 +307,7 @@ static void fire_PMC_interrupt(PowerPCCPU *cpu)
         env->spr[SPR_POWER_MMCR0] |= MMCR0_PMAO;
     }
 
-    /* PMC interrupt not implemented yet */
-    return;
+    helper_ebb_perfm_excp(env);
 }
 
 /* This helper assumes that the PMC is running. */
-- 
2.34.1