refactor: Add specialized hstatus_csr_t

Author: YenHaoChen

riscv/csrs.cc

@@ -1851,3 +1851,16 @@ void mtval2_csr_t::verify_permissions(insn_t insn, bool write) const {
   if (!proc->extension_enabled('H') && !proc->extension_enabled(EXT_SSDBLTRP))
     throw trap_illegal_instruction(insn.bits());
 }
+
+hstatus_csr_t::hstatus_csr_t(processor_t* const proc, const reg_t addr):
+  basic_csr_t(proc, addr, set_field((reg_t)0, HSTATUS_VSXL, xlen_to_uxl(proc->get_const_xlen()))) {
+}
+
+bool hstatus_csr_t::unlogged_write(const reg_t val) noexcept {
+  const reg_t mask = HSTATUS_VTSR | HSTATUS_VTW
+    | (proc->supports_impl(IMPL_MMU) ? HSTATUS_VTVM : 0)
+    | HSTATUS_HU | HSTATUS_SPVP | HSTATUS_SPV | HSTATUS_GVA;
+
+  const reg_t new_hstatus = (read() & ~mask) | (val & mask);
+  return basic_csr_t::unlogged_write(new_hstatus);
+}

riscv/csrs.h

@@ -891,4 +891,11 @@ class mtval2_csr_t: public hypervisor_csr_t {
   mtval2_csr_t(processor_t* const proc, const reg_t addr);
   virtual void verify_permissions(insn_t insn, bool write) const override;
 };
+
+class hstatus_csr_t final: public basic_csr_t {
+ public:
+  hstatus_csr_t(processor_t* const proc, const reg_t addr);
+ protected:
+  virtual bool unlogged_write(const reg_t val) noexcept override;
+};
 #endif

riscv/processor.cc

@@ -297,11 +297,7 @@ void state_t::reset(processor_t* const proc, reg_t max_isa)
   csrmap[CSR_SCAUSE] = scause = std::make_shared<virtualized_csr_t>(proc, nonvirtual_scause, vscause);
   csrmap[CSR_MTVAL2] = mtval2 = std::make_shared<mtval2_csr_t>(proc, CSR_MTVAL2);
   csrmap[CSR_MTINST] = mtinst = std::make_shared<hypervisor_csr_t>(proc, CSR_MTINST);
-  const reg_t hstatus_init = set_field((reg_t)0, HSTATUS_VSXL, xlen_to_uxl(proc->get_const_xlen()));
-  const reg_t hstatus_mask = HSTATUS_VTSR | HSTATUS_VTW
-    | (proc->supports_impl(IMPL_MMU) ? HSTATUS_VTVM : 0)
-    | HSTATUS_HU | HSTATUS_SPVP | HSTATUS_SPV | HSTATUS_GVA;
-  csrmap[CSR_HSTATUS] = hstatus = std::make_shared<masked_csr_t>(proc, CSR_HSTATUS, hstatus_mask, hstatus_init);
+  csrmap[CSR_HSTATUS] = hstatus = std::make_shared<hstatus_csr_t>(proc, CSR_HSTATUS);
   csrmap[CSR_HGEIE] = std::make_shared<const_csr_t>(proc, CSR_HGEIE, 0);
   csrmap[CSR_HGEIP] = std::make_shared<const_csr_t>(proc, CSR_HGEIP, 0);
   csrmap[CSR_HIDELEG] = hideleg = std::make_shared<hideleg_csr_t>(proc, CSR_HIDELEG, mideleg);