target/riscv/kvm: handle the exit with debug reason

If the breakpoint belongs to the userspace then set the ret value.

Signed-off-by: Chao Du <duchao@eswincomputing.com>
Reviewed-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Acked-by: Alistair Francis <alistair.francis@wdc.com>
Message-ID: <20240606014501.20763-3-duchao@eswincomputing.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

target/riscv/kvm/kvm-cpu.c

@@ -1555,6 +1555,21 @@ static int kvm_riscv_handle_csr(CPUState *cs, struct kvm_run *run)
     return ret;
 }
 
+static bool kvm_riscv_handle_debug(CPUState *cs)
+{
+    RISCVCPU *cpu = RISCV_CPU(cs);
+    CPURISCVState *env = &cpu->env;
+
+    /* Ensure PC is synchronised */
+    kvm_cpu_synchronize_state(cs);
+
+    if (kvm_find_sw_breakpoint(cs, env->pc)) {
+        return true;
+    }
+
+    return false;
+}
+
 int kvm_arch_handle_exit(CPUState *cs, struct kvm_run *run)
 {
     int ret = 0;
@@ -1565,6 +1580,11 @@ int kvm_arch_handle_exit(CPUState *cs, struct kvm_run *run)
     case KVM_EXIT_RISCV_CSR:
         ret = kvm_riscv_handle_csr(cs, run);
         break;
+    case KVM_EXIT_DEBUG:
+        if (kvm_riscv_handle_debug(cs)) {
+            ret = EXCP_DEBUG;
+        }
+        break;
     default:
         qemu_log_mask(LOG_UNIMP, "%s: un-handled exit reason %d\n",
                       __func__, run->exit_reason);