hw/riscv/riscv-iommu: add hpm events mmio write

To support hpm events mmio writes, done via
riscv_iommu_process_hpmevt_write(), we're also adding the 'hpm-counters'
IOMMU property that are used to determine the amount of counters
available in the IOMMU.

Note that everything we did so far didn't change any IOMMU behavior
because we're still not advertising HPM capability to software. This
will be done in the next patch.

Signed-off-by: Tomasz Jeznach <tjeznach@rivosinc.com>
Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Acked-by: Alistair Francis <alistair.francis@wdc.com>
Message-ID: <20250224190826.1858473-9-dbarboza@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

diff --git a/hw/riscv/riscv-iommu-hpm.c b/hw/riscv/riscv-iommu-hpm.c
index 1cea6b1df18eae7013ea130e0d31bacc485d3051..5518c287a5bddf73d164592be17328fd1aaa6e11 100644 (file)
--- a/hw/riscv/riscv-iommu-hpm.c
+++ b/hw/riscv/riscv-iommu-hpm.c
@@ -281,3 +281,91 @@ void riscv_iommu_process_hpmcycle_write(RISCVIOMMUState *s)
     s->hpmcycle_prev = get_cycles();
     hpm_setup_timer(s, s->hpmcycle_val);
 }
+
+static inline bool check_valid_event_id(unsigned event_id)
+{
+    return event_id > RISCV_IOMMU_HPMEVENT_INVALID &&
+           event_id < RISCV_IOMMU_HPMEVENT_MAX;
+}
+
+static gboolean hpm_event_equal(gpointer key, gpointer value, gpointer udata)
+{
+    uint32_t *pair = udata;
+
+    if (GPOINTER_TO_UINT(value) & (1 << pair[0])) {
+        pair[1] = GPOINTER_TO_UINT(key);
+        return true;
+    }
+
+    return false;
+}
+
+/* Caller must check ctr_idx against hpm_ctrs to see if its supported or not. */
+static void update_event_map(RISCVIOMMUState *s, uint64_t value,
+                             uint32_t ctr_idx)
+{
+    unsigned event_id = get_field(value, RISCV_IOMMU_IOHPMEVT_EVENT_ID);
+    uint32_t pair[2] = { ctr_idx, RISCV_IOMMU_HPMEVENT_INVALID };
+    uint32_t new_value = 1 << ctr_idx;
+    gpointer data;
+
+    /*
+     * If EventID field is RISCV_IOMMU_HPMEVENT_INVALID
+     * remove the current mapping.
+     */
+    if (event_id == RISCV_IOMMU_HPMEVENT_INVALID) {
+        data = g_hash_table_find(s->hpm_event_ctr_map, hpm_event_equal, pair);
+
+        new_value = GPOINTER_TO_UINT(data) & ~(new_value);
+        if (new_value != 0) {
+            g_hash_table_replace(s->hpm_event_ctr_map,
+                                 GUINT_TO_POINTER(pair[1]),
+                                 GUINT_TO_POINTER(new_value));
+        } else {
+            g_hash_table_remove(s->hpm_event_ctr_map,
+                                GUINT_TO_POINTER(pair[1]));
+        }
+
+        return;
+    }
+
+    /* Update the counter mask if the event is already enabled. */
+    if (g_hash_table_lookup_extended(s->hpm_event_ctr_map,
+                                     GUINT_TO_POINTER(event_id),
+                                     NULL,
+                                     &data)) {
+        new_value |= GPOINTER_TO_UINT(data);
+    }
+
+    g_hash_table_insert(s->hpm_event_ctr_map,
+                        GUINT_TO_POINTER(event_id),
+                        GUINT_TO_POINTER(new_value));
+}
+
+void riscv_iommu_process_hpmevt_write(RISCVIOMMUState *s, uint32_t evt_reg)
+{
+    const uint32_t ctr_idx = (evt_reg - RISCV_IOMMU_REG_IOHPMEVT_BASE) >> 3;
+    const uint32_t ovf = riscv_iommu_reg_get32(s, RISCV_IOMMU_REG_IOCOUNTOVF);
+    uint64_t val = riscv_iommu_reg_get64(s, evt_reg);
+
+    if (ctr_idx >= s->hpm_cntrs) {
+        return;
+    }
+
+    /* Clear OF bit in IOCNTOVF if it's being cleared in IOHPMEVT register. */
+    if (get_field(ovf, BIT(ctr_idx + 1)) &&
+        !get_field(val, RISCV_IOMMU_IOHPMEVT_OF)) {
+        /* +1 to offset CYCLE register OF bit. */
+        riscv_iommu_reg_mod32(
+            s, RISCV_IOMMU_REG_IOCOUNTOVF, 0, BIT(ctr_idx + 1));
+    }
+
+    if (!check_valid_event_id(get_field(val, RISCV_IOMMU_IOHPMEVT_EVENT_ID))) {
+        /* Reset EventID (WARL) field to invalid. */
+        val = set_field(val, RISCV_IOMMU_IOHPMEVT_EVENT_ID,
+            RISCV_IOMMU_HPMEVENT_INVALID);
+        riscv_iommu_reg_set64(s, evt_reg, val);
+    }
+
+    update_event_map(s, val, ctr_idx);
+}

diff --git a/hw/riscv/riscv-iommu-hpm.h b/hw/riscv/riscv-iommu-hpm.h
index 0cd550975d3efcb3e64459a7d8b5f7389ff2d6cf..5fc4ef2e8bd5ff9ee2ceb00f6bc692dc2213b871 100644 (file)
--- a/hw/riscv/riscv-iommu-hpm.h
+++ b/hw/riscv/riscv-iommu-hpm.h
@@ -28,5 +28,6 @@ void riscv_iommu_hpm_incr_ctr(RISCVIOMMUState *s, RISCVIOMMUContext *ctx,
 void riscv_iommu_hpm_timer_cb(void *priv);
 void riscv_iommu_process_iocntinh_cy(RISCVIOMMUState *s, bool prev_cy_inh);
 void riscv_iommu_process_hpmcycle_write(RISCVIOMMUState *s);
+void riscv_iommu_process_hpmevt_write(RISCVIOMMUState *s, uint32_t evt_reg);
 
 #endif

diff --git a/hw/riscv/riscv-iommu.c b/hw/riscv/riscv-iommu.c
index 821ecba3a4c74dad49231a25aff2d1c931e1b749..cdbb84818130e92a31c19140ee01b3188025ff8a 100644 (file)
--- a/hw/riscv/riscv-iommu.c
+++ b/hw/riscv/riscv-iommu.c
@@ -2040,7 +2040,7 @@ static void riscv_iommu_process_hpm_writes(RISCVIOMMUState *s,
 
     case RISCV_IOMMU_REG_IOHPMEVT_BASE ...
         RISCV_IOMMU_REG_IOHPMEVT(RISCV_IOMMU_IOCOUNT_NUM) + 4:
-        /* not yet implemented */
+        riscv_iommu_process_hpmevt_write(s, regb & ~7);
         break;
     }
 }
@@ -2487,6 +2487,8 @@ static const Property riscv_iommu_properties[] = {
     DEFINE_PROP_BOOL("g-stage", RISCVIOMMUState, enable_g_stage, TRUE),
     DEFINE_PROP_LINK("downstream-mr", RISCVIOMMUState, target_mr,
         TYPE_MEMORY_REGION, MemoryRegion *),
+    DEFINE_PROP_UINT8("hpm-counters", RISCVIOMMUState, hpm_cntrs,
+                      RISCV_IOMMU_IOCOUNT_NUM),
 };
 
 static void riscv_iommu_class_init(ObjectClass *klass, void* data)

diff --git a/hw/riscv/riscv-iommu.h b/hw/riscv/riscv-iommu.h
index 2fef6eed273bef086a0cadd8600751d484604e50..a31aa62144f4b6b85b1d6b6a7e28a4285958154e 100644 (file)
--- a/hw/riscv/riscv-iommu.h
+++ b/hw/riscv/riscv-iommu.h
@@ -90,6 +90,7 @@ struct RISCVIOMMUState {
 
     /* HPM event counters */
     GHashTable *hpm_event_ctr_map; /* Mapping of events to counters */
+    uint8_t hpm_cntrs;
 };
 
 void riscv_iommu_pci_setup_iommu(RISCVIOMMUState *iommu, PCIBus *bus,