[PATCH 15/19] target/ppc/pmu_book3s_helper: enable counter negative for all PMCs

[Daniel Henrique Barboza]

All performance monitor counters can trigger a counter negative
condition if the proper MMCR0 bits are set. This patch does that by
doing the following:

- pmc_counter_negative_enabled() will check whether a given PMC is
eligible to trigger the counter negative alert;

- get_counter_neg_timeout() will return the timeout for the counter
negative condition for a given PMC, or -1 if the PMC is not able to
trigger this alert;

- the existing counter_negative_cond_enabled() now must consider the
counter negative bit for PMCs 2-6, MMCR0_PMCjCE;

- set_PMU_excp_timer() will now search all existing PMCs for the
shortest counter negative timeout. The shortest timeout will be used to
set the PMC interrupt timer.

This change makes most EBB powepc kernel tests pass, validating that the
existing EBB logic is consistent. There are a few tests that aren't passing
due to additional PMU bits and perf events that aren't covered yet.
We'll attempt to cover some of those in the next patches.

Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
---
 target/ppc/cpu.h               |  1 +
 target/ppc/pmu_book3s_helper.c | 96 ++++++++++++++++++++++++++++++----
 2 files changed, 87 insertions(+), 10 deletions(-)

diff --git a/target/ppc/cpu.h b/target/ppc/cpu.h
index 5c81d459f4..1aa1fd42af 100644
--- a/target/ppc/cpu.h
+++ b/target/ppc/cpu.h
@@ -351,6 +351,7 @@ typedef struct ppc_v3_pate_t {
 #define MMCR0_FCECE PPC_BIT(38)         /* FC on Enabled Cond or Event */
 #define MMCR0_PMCC  PPC_BITMASK(44, 45) /* PMC Control */
 #define MMCR0_PMC1CE PPC_BIT(48)
+#define MMCR0_PMCjCE PPC_BIT(49)
 
 #define MMCR1_PMC1SEL_SHIFT (63 - 39)
 #define MMCR1_PMC1SEL PPC_BITMASK(32, 39)
diff --git a/target/ppc/pmu_book3s_helper.c b/target/ppc/pmu_book3s_helper.c
index 7126e9b3d5..c5c5ab38c9 100644
--- a/target/ppc/pmu_book3s_helper.c
+++ b/target/ppc/pmu_book3s_helper.c
@@ -143,22 +143,98 @@ static int64_t get_CYC_timeout(CPUPPCState *env, int sprn)
     return muldiv64(remaining_cyc, NANOSECONDS_PER_SECOND, PPC_CPU_FREQ);
 }
 
-static void set_PMU_excp_timer(CPUPPCState *env)
+static bool pmc_counter_negative_enabled(CPUPPCState *env, int sprn)
 {
-    uint64_t timeout, now;
+    switch (sprn) {
+    case SPR_POWER_PMC1:
+        return env->spr[SPR_POWER_MMCR0] & MMCR0_PMC1CE;
 
-    if (!(env->spr[SPR_POWER_MMCR0] & MMCR0_PMC1CE)) {
-        return;
+    case SPR_POWER_PMC2:
+    case SPR_POWER_PMC3:
+    case SPR_POWER_PMC4:
+    case SPR_POWER_PMC5:
+    case SPR_POWER_PMC6:
+        return env->spr[SPR_POWER_MMCR0] & MMCR0_PMCjCE;
+
+    default:
+        break;
     }
 
-    switch (get_PMC_event(env, SPR_POWER_PMC1)) {
-    case 0x2:
-        timeout = get_INST_CMPL_timeout(env, SPR_POWER_PMC1);
+    return false;
+}
+
+static int64_t get_counter_neg_timeout(CPUPPCState *env, int sprn)
+{
+    int64_t timeout = -1;
+
+    if (!pmc_counter_negative_enabled(env, sprn)) {
+        return -1;
+    }
+
+    if (env->spr[sprn] >= COUNTER_NEGATIVE_VAL) {
+        return 0;
+    }
+
+    switch (sprn) {
+    case SPR_POWER_PMC1:
+    case SPR_POWER_PMC2:
+    case SPR_POWER_PMC3:
+    case SPR_POWER_PMC4:
+        switch (get_PMC_event(env, sprn)) {
+        case 0x2:
+            timeout = get_INST_CMPL_timeout(env, sprn);
+            break;
+        case 0x1E:
+            timeout = get_CYC_timeout(env, sprn);
+            break;
+        }
+
         break;
-    case 0x1e:
-        timeout = get_CYC_timeout(env, SPR_POWER_PMC1);
+    case SPR_POWER_PMC5:
+        timeout = get_INST_CMPL_timeout(env, sprn);
+        break;
+    case SPR_POWER_PMC6:
+        timeout = get_CYC_timeout(env, sprn);
         break;
     default:
+        break;
+    }
+
+    return timeout;
+}
+
+static void set_PMU_excp_timer(CPUPPCState *env)
+{
+    int64_t timeout = -1;
+    uint64_t now;
+    int i;
+
+    /*
+     * Scroll through all PMCs and check which one is closer to a
+     * counter negative timeout.
+     */
+    for (i = SPR_POWER_PMC1; i <= SPR_POWER_PMC6; i++) {
+        int64_t curr_timeout = get_counter_neg_timeout(env, i);
+
+        if (curr_timeout == -1) {
+            continue;
+        }
+
+        if (curr_timeout == 0) {
+            timeout = 0;
+            break;
+        }
+
+        if (timeout == -1 || timeout > curr_timeout) {
+            timeout = curr_timeout;
+        }
+    }
+
+    /*
+     * This can happen if counter negative conditions were enabled
+     * without any events to be sampled.
+     */
+    if (timeout == -1) {
         return;
     }
 
@@ -204,7 +280,7 @@ void cpu_ppc_pmu_timer_init(CPUPPCState *env)
 
 static bool counter_negative_cond_enabled(uint64_t mmcr0)
 {
-    return mmcr0 & MMCR0_PMC1CE;
+    return mmcr0 & (MMCR0_PMC1CE | MMCR0_PMCjCE);
 }
 
 void helper_store_mmcr0(CPUPPCState *env, target_ulong value)
-- 
2.31.1