hw/riscv: add IOMMU HPM trace events

Add a handful of trace events to allow for an easier time debugging the
HPM feature.

Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Acked-by: Alistair Francis <alistair.francis@wdc.com>
Message-ID: <20250224190826.1858473-11-dbarboza@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

hw/riscv/riscv-iommu-hpm.c

@@ -39,6 +39,8 @@ uint64_t riscv_iommu_hpmcycle_read(RISCVIOMMUState *s)
     const uint64_t ctr_prev = s->hpmcycle_prev;
     const uint64_t ctr_val = s->hpmcycle_val;
 
+    trace_riscv_iommu_hpm_read(cycle, inhibit, ctr_prev, ctr_val);
+
     if (get_field(inhibit, RISCV_IOMMU_IOCOUNTINH_CY)) {
         /*
          * Counter should not increment if inhibit bit is set. We can't really
@@ -61,6 +63,8 @@ static void hpm_incr_ctr(RISCVIOMMUState *s, uint32_t ctr_idx)
     cntr_val = ldq_le_p(&s->regs_rw[RISCV_IOMMU_REG_IOHPMCTR_BASE + off]);
     stq_le_p(&s->regs_rw[RISCV_IOMMU_REG_IOHPMCTR_BASE + off], cntr_val + 1);
 
+    trace_riscv_iommu_hpm_incr_ctr(cntr_val);
+
     /* Handle the overflow scenario. */
     if (cntr_val == UINT64_MAX) {
         /*
@@ -244,6 +248,8 @@ void riscv_iommu_process_iocntinh_cy(RISCVIOMMUState *s, bool prev_cy_inh)
         return;
     }
 
+    trace_riscv_iommu_hpm_iocntinh_cy(prev_cy_inh);
+
     if (!(inhibit & RISCV_IOMMU_IOCOUNTINH_CY)) {
         /*
          * Cycle counter is enabled. Just start the timer again and update
@@ -268,6 +274,8 @@ void riscv_iommu_process_hpmcycle_write(RISCVIOMMUState *s)
     const uint64_t val = riscv_iommu_reg_get64(s, RISCV_IOMMU_REG_IOHPMCYCLES);
     const uint32_t ovf = riscv_iommu_reg_get32(s, RISCV_IOMMU_REG_IOCOUNTOVF);
 
+    trace_riscv_iommu_hpm_cycle_write(ovf, val);
+
     /*
      * Clear OF bit in IOCNTOVF if it's being cleared in IOHPMCYCLES register.
      */
@@ -352,6 +360,8 @@ void riscv_iommu_process_hpmevt_write(RISCVIOMMUState *s, uint32_t evt_reg)
         return;
     }
 
+    trace_riscv_iommu_hpm_evt_write(ctr_idx, ovf, val);
+
     /* 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)) {

hw/riscv/trace-events

@@ -19,3 +19,8 @@ riscv_iommu_sys_irq_sent(uint32_t vector) "IRQ sent to vector %u"
 riscv_iommu_sys_msi_sent(uint32_t vector, uint64_t msi_addr, uint32_t msi_data, uint32_t result) "MSI sent to vector %u msi_addr 0x%"PRIx64" msi_data 0x%x result %u"
 riscv_iommu_sys_reset_hold(int reset_type) "reset type %d"
 riscv_iommu_pci_reset_hold(int reset_type) "reset type %d"
+riscv_iommu_hpm_read(uint64_t cycle, uint32_t inhibit, uint64_t ctr_prev, uint64_t ctr_val) "cycle 0x%"PRIx64" inhibit 0x%x ctr_prev 0x%"PRIx64" ctr_val 0x%"PRIx64
+riscv_iommu_hpm_incr_ctr(uint64_t cntr_val) "cntr_val 0x%"PRIx64
+riscv_iommu_hpm_iocntinh_cy(bool prev_cy_inh) "prev_cy_inh %d"
+riscv_iommu_hpm_cycle_write(uint32_t ovf, uint64_t val) "ovf 0x%x val 0x%"PRIx64
+riscv_iommu_hpm_evt_write(uint32_t ctr_idx, uint32_t ovf, uint64_t val) "ctr_idx 0x%x ovf 0x%x val 0x%"PRIx64