Handle read-modify-write i/o with icount

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Merge remote-tracking branch 'remotes/rth/tags/pull-tcg-20180411' into staging

Handle read-modify-write i/o with icount

# gpg: Signature made Wed 11 Apr 2018 00:07:23 BST
# gpg:                using RSA key 64DF38E8AF7E215F
# gpg: Good signature from "Richard Henderson <richard.henderson@linaro.org>"
# Primary key fingerprint: 7A48 1E78 868B 4DB6 A85A  05C0 64DF 38E8 AF7E 215F

* remotes/rth/tags/pull-tcg-20180411:
  icount: fix cpu_restore_state_from_tb for non-tb-exit cases

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

accel/tcg/cpu-exec-common.c

@@ -27,10 +27,8 @@ bool tcg_allowed;
 /* exit the current TB, but without causing any exception to be raised */
 void cpu_loop_exit_noexc(CPUState *cpu)
 {
-    /* XXX: restore cpu registers saved in host registers */
-
     cpu->exception_index = -1;
-    siglongjmp(cpu->jmp_env, 1);
+    cpu_loop_exit(cpu);
 }
 
 #if defined(CONFIG_SOFTMMU)
@@ -65,15 +63,17 @@ void cpu_reloading_memory_map(void)
 
 void cpu_loop_exit(CPUState *cpu)
 {
+    /* Undo the setting in cpu_tb_exec.  */
+    cpu->can_do_io = 1;
     siglongjmp(cpu->jmp_env, 1);
 }
 
 void cpu_loop_exit_restore(CPUState *cpu, uintptr_t pc)
 {
     if (pc) {
-        cpu_restore_state(cpu, pc);
+        cpu_restore_state(cpu, pc, true);
     }
-    siglongjmp(cpu->jmp_env, 1);
+    cpu_loop_exit(cpu);
 }
 
 void cpu_loop_exit_atomic(CPUState *cpu, uintptr_t pc)

accel/tcg/cpu-exec.c

@@ -704,7 +704,6 @@ int cpu_exec(CPUState *cpu)
         g_assert(cpu == current_cpu);
         g_assert(cc == CPU_GET_CLASS(cpu));
 #endif /* buggy compiler */
-        cpu->can_do_io = 1;
         tb_lock_reset();
         if (qemu_mutex_iothread_locked()) {
             qemu_mutex_unlock_iothread();

accel/tcg/translate-all.c

@@ -299,9 +299,11 @@ static int encode_search(TranslationBlock *tb, uint8_t *block)
 
 /* The cpu state corresponding to 'searched_pc' is restored.
  * Called with tb_lock held.
+ * When reset_icount is true, current TB will be interrupted and
+ * icount should be recalculated.
  */
 static int cpu_restore_state_from_tb(CPUState *cpu, TranslationBlock *tb,
-                                     uintptr_t searched_pc)
+                                     uintptr_t searched_pc, bool reset_icount)
 {
     target_ulong data[TARGET_INSN_START_WORDS] = { tb->pc };
     uintptr_t host_pc = (uintptr_t)tb->tc.ptr;
@@ -333,14 +335,12 @@ static int cpu_restore_state_from_tb(CPUState *cpu, TranslationBlock *tb,
     return -1;
 
  found:
-    if (tb->cflags & CF_USE_ICOUNT) {
+    if (reset_icount && (tb->cflags & CF_USE_ICOUNT)) {
         assert(use_icount);
-        /* Reset the cycle counter to the start of the block.  */
+        /* Reset the cycle counter to the start of the block
-        cpu->icount_decr.u16.low += num_insns;
+           and shift if to the number of actually executed instructions */
-        /* Clear the IO flag.  */
+        cpu->icount_decr.u16.low += num_insns - i;
-        cpu->can_do_io = 0;
     }
-    cpu->icount_decr.u16.low -= i;
     restore_state_to_opc(env, tb, data);
 
 #ifdef CONFIG_PROFILER
@@ -351,7 +351,7 @@ static int cpu_restore_state_from_tb(CPUState *cpu, TranslationBlock *tb,
     return 0;
 }
 
-bool cpu_restore_state(CPUState *cpu, uintptr_t host_pc)
+bool cpu_restore_state(CPUState *cpu, uintptr_t host_pc, bool will_exit)
 {
     TranslationBlock *tb;
     bool r = false;
@@ -377,7 +377,7 @@ bool cpu_restore_state(CPUState *cpu, uintptr_t host_pc)
         tb_lock();
         tb = tb_find_pc(host_pc);
         if (tb) {
-            cpu_restore_state_from_tb(cpu, tb, host_pc);
+            cpu_restore_state_from_tb(cpu, tb, host_pc, will_exit);
             if (tb->cflags & CF_NOCACHE) {
                 /* one-shot translation, invalidate it immediately */
                 tb_phys_invalidate(tb, -1);
@@ -1511,7 +1511,8 @@ void tb_invalidate_phys_page_range(tb_page_addr_t start, tb_page_addr_t end,
                 restore the CPU state */
 
                 current_tb_modified = 1;
-                cpu_restore_state_from_tb(cpu, current_tb, cpu->mem_io_pc);
+                cpu_restore_state_from_tb(cpu, current_tb,
+                                          cpu->mem_io_pc, true);
                 cpu_get_tb_cpu_state(env, &current_pc, &current_cs_base,
                                      &current_flags);
             }
@@ -1634,7 +1635,7 @@ static bool tb_invalidate_phys_page(tb_page_addr_t addr, uintptr_t pc)
                    restore the CPU state */
 
             current_tb_modified = 1;
-            cpu_restore_state_from_tb(cpu, current_tb, pc);
+            cpu_restore_state_from_tb(cpu, current_tb, pc, true);
             cpu_get_tb_cpu_state(env, &current_pc, &current_cs_base,
                                  &current_flags);
         }
@@ -1700,7 +1701,7 @@ void tb_check_watchpoint(CPUState *cpu)
     tb = tb_find_pc(cpu->mem_io_pc);
     if (tb) {
         /* We can use retranslation to find the PC.  */
-        cpu_restore_state_from_tb(cpu, tb, cpu->mem_io_pc);
+        cpu_restore_state_from_tb(cpu, tb, cpu->mem_io_pc, true);
         tb_phys_invalidate(tb, -1);
     } else {
         /* The exception probably happened in a helper.  The CPU state should
@@ -1736,7 +1737,7 @@ void cpu_io_recompile(CPUState *cpu, uintptr_t retaddr)
         cpu_abort(cpu, "cpu_io_recompile: could not find TB for pc=%p",
                   (void *)retaddr);
     }
-    cpu_restore_state_from_tb(cpu, tb, retaddr);
+    cpu_restore_state_from_tb(cpu, tb, retaddr, true);
 
     /* On MIPS and SH, delay slot instructions can only be restarted if
        they were already the first instruction in the TB.  If this is not

accel/tcg/user-exec.c

@@ -168,7 +168,7 @@ static inline int handle_cpu_signal(uintptr_t pc, siginfo_t *info,
     }
 
     /* Now we have a real cpu fault.  */
-    cpu_restore_state(cpu, pc);
+    cpu_restore_state(cpu, pc, true);
 
     sigprocmask(SIG_SETMASK, old_set, NULL);
     cpu_loop_exit(cpu);

hw/misc/mips_itu.c

@@ -174,10 +174,9 @@ static void wake_blocked_threads(ITCStorageCell *c)
 static void QEMU_NORETURN block_thread_and_exit(ITCStorageCell *c)
 {
     c->blocked_threads |= 1ULL << current_cpu->cpu_index;
-    cpu_restore_state(current_cpu, current_cpu->mem_io_pc);
     current_cpu->halted = 1;
     current_cpu->exception_index = EXCP_HLT;
-    cpu_loop_exit(current_cpu);
+    cpu_loop_exit_restore(current_cpu, current_cpu->mem_io_pc);
 }
 
 /* ITC Bypass View */

include/exec/exec-all.h

@@ -50,13 +50,16 @@ void cpu_gen_init(void);
  * cpu_restore_state:
  * @cpu: the vCPU state is to be restore to
  * @searched_pc: the host PC the fault occurred at
+ * @will_exit: true if the TB executed will be interrupted after some
+               cpu adjustments. Required for maintaining the correct
+               icount valus
  * @return: true if state was restored, false otherwise
  *
  * Attempt to restore the state for a fault occurring in translated
  * code. If the searched_pc is not in translated code no state is
  * restored and the function returns false.
  */
-bool cpu_restore_state(CPUState *cpu, uintptr_t searched_pc);
+bool cpu_restore_state(CPUState *cpu, uintptr_t searched_pc, bool will_exit);
 
 void QEMU_NORETURN cpu_loop_exit_noexc(CPUState *cpu);
 void QEMU_NORETURN cpu_io_recompile(CPUState *cpu, uintptr_t retaddr);

target/alpha/helper.c

@@ -482,7 +482,7 @@ void QEMU_NORETURN dynamic_excp(CPUAlphaState *env, uintptr_t retaddr,
     cs->exception_index = excp;
     env->error_code = error;
     if (retaddr) {
-        cpu_restore_state(cs, retaddr);
+        cpu_restore_state(cs, retaddr, true);
         /* Floating-point exceptions (our only users) point to the next PC.  */
         env->pc += 4;
     }

target/alpha/mem_helper.c

@@ -34,7 +34,7 @@ void alpha_cpu_do_unaligned_access(CPUState *cs, vaddr addr,
     uint64_t pc;
     uint32_t insn;
 
-    cpu_restore_state(cs, retaddr);
+    cpu_restore_state(cs, retaddr, true);
 
     pc = env->pc;
     insn = cpu_ldl_code(env, pc);
@@ -56,13 +56,11 @@ void alpha_cpu_do_transaction_failed(CPUState *cs, hwaddr physaddr,
     AlphaCPU *cpu = ALPHA_CPU(cs);
     CPUAlphaState *env = &cpu->env;
 
-    cpu_restore_state(cs, retaddr);
-
     env->trap_arg0 = addr;
     env->trap_arg1 = access_type == MMU_DATA_STORE ? 1 : 0;
     cs->exception_index = EXCP_MCHK;
     env->error_code = 0;
-    cpu_loop_exit(cs);
+    cpu_loop_exit_restore(cs, retaddr);
 }
 
 /* try to fill the TLB and return an exception if error. If retaddr is

target/arm/op_helper.c

@@ -180,7 +180,7 @@ void tlb_fill(CPUState *cs, target_ulong addr, int size,
         ARMCPU *cpu = ARM_CPU(cs);
 
         /* now we have a real cpu fault */
-        cpu_restore_state(cs, retaddr);
+        cpu_restore_state(cs, retaddr, true);
 
         deliver_fault(cpu, addr, access_type, mmu_idx, &fi);
     }
@@ -195,7 +195,7 @@ void arm_cpu_do_unaligned_access(CPUState *cs, vaddr vaddr,
     ARMMMUFaultInfo fi = {};
 
     /* now we have a real cpu fault */
-    cpu_restore_state(cs, retaddr);
+    cpu_restore_state(cs, retaddr, true);
 
     fi.type = ARMFault_Alignment;
     deliver_fault(cpu, vaddr, access_type, mmu_idx, &fi);
@@ -215,7 +215,7 @@ void arm_cpu_do_transaction_failed(CPUState *cs, hwaddr physaddr,
     ARMMMUFaultInfo fi = {};
 
     /* now we have a real cpu fault */
-    cpu_restore_state(cs, retaddr);
+    cpu_restore_state(cs, retaddr, true);
 
     fi.ea = arm_extabort_type(response);
     fi.type = ARMFault_SyncExternal;

target/cris/op_helper.c

@@ -54,7 +54,7 @@ void tlb_fill(CPUState *cs, target_ulong addr, int size,
     if (unlikely(ret)) {
         if (retaddr) {
             /* now we have a real cpu fault */
-            if (cpu_restore_state(cs, retaddr)) {
+            if (cpu_restore_state(cs, retaddr, true)) {
                 /* Evaluate flags after retranslation. */
                 helper_top_evaluate_flags(env);
             }

target/i386/helper.c

@@ -991,7 +991,7 @@ void cpu_report_tpr_access(CPUX86State *env, TPRAccess access)
 
         cpu_interrupt(cs, CPU_INTERRUPT_TPR);
     } else if (tcg_enabled()) {
-        cpu_restore_state(cs, cs->mem_io_pc);
+        cpu_restore_state(cs, cs->mem_io_pc, false);
 
         apic_handle_tpr_access_report(cpu->apic_state, env->eip, access);
     }

target/i386/svm_helper.c

@@ -584,7 +584,7 @@ void cpu_vmexit(CPUX86State *env, uint32_t exit_code, uint64_t exit_info_1,
 {
     CPUState *cs = CPU(x86_env_get_cpu(env));
 
-    cpu_restore_state(cs, retaddr);
+    cpu_restore_state(cs, retaddr, true);
 
     qemu_log_mask(CPU_LOG_TB_IN_ASM, "vmexit(%08x, %016" PRIx64 ", %016"
                   PRIx64 ", " TARGET_FMT_lx ")!\n",

target/m68k/op_helper.c

@@ -1056,7 +1056,7 @@ void HELPER(chk)(CPUM68KState *env, int32_t val, int32_t ub)
         CPUState *cs = CPU(m68k_env_get_cpu(env));
 
         /* Recover PC and CC_OP for the beginning of the insn.  */
-        cpu_restore_state(cs, GETPC());
+        cpu_restore_state(cs, GETPC(), true);
 
         /* flags have been modified by gen_flush_flags() */
         env->cc_op = CC_OP_FLAGS;
@@ -1087,7 +1087,7 @@ void HELPER(chk2)(CPUM68KState *env, int32_t val, int32_t lb, int32_t ub)
         CPUState *cs = CPU(m68k_env_get_cpu(env));
 
         /* Recover PC and CC_OP for the beginning of the insn.  */
-        cpu_restore_state(cs, GETPC());
+        cpu_restore_state(cs, GETPC(), true);
 
         /* flags have been modified by gen_flush_flags() */
         env->cc_op = CC_OP_FLAGS;

target/moxie/helper.c

@@ -48,7 +48,7 @@ void helper_raise_exception(CPUMoxieState *env, int ex)
     /* Stash the exception type.  */
     env->sregs[2] = ex;
     /* Stash the address where the exception occurred.  */
-    cpu_restore_state(cs, GETPC());
+    cpu_restore_state(cs, GETPC(), true);
     env->sregs[5] = env->pc;
     /* Jump to the exception handline routine.  */
     env->pc = env->sregs[1];

target/openrisc/sys_helper.c

@@ -46,7 +46,7 @@ void HELPER(mtspr)(CPUOpenRISCState *env,
         break;
 
     case TO_SPR(0, 16): /* NPC */
-        cpu_restore_state(cs, GETPC());
+        cpu_restore_state(cs, GETPC(), true);
         /* ??? Mirror or1ksim in not trashing delayed branch state
            when "jumping" to the current instruction.  */
         if (env->pc != rb) {
@@ -146,7 +146,7 @@ void HELPER(mtspr)(CPUOpenRISCState *env,
     case TO_SPR(8, 0):  /* PMR */
         env->pmr = rb;
         if (env->pmr & PMR_DME || env->pmr & PMR_SME) {
-            cpu_restore_state(cs, GETPC());
+            cpu_restore_state(cs, GETPC(), true);
             env->pc += 4;
             cs->halted = 1;
             raise_exception(cpu, EXCP_HALTED);
@@ -230,14 +230,14 @@ target_ulong HELPER(mfspr)(CPUOpenRISCState *env,
         return env->evbar;
 
     case TO_SPR(0, 16): /* NPC (equals PC) */
-        cpu_restore_state(cs, GETPC());
+        cpu_restore_state(cs, GETPC(), false);
         return env->pc;
 
     case TO_SPR(0, 17): /* SR */
         return cpu_get_sr(env);
 
     case TO_SPR(0, 18): /* PPC */
-        cpu_restore_state(cs, GETPC());
+        cpu_restore_state(cs, GETPC(), false);
         return env->ppc;
 
     case TO_SPR(0, 32): /* EPCR */

target/tricore/op_helper.c

@@ -31,7 +31,7 @@ raise_exception_sync_internal(CPUTriCoreState *env, uint32_t class, int tin,
 {
     CPUState *cs = CPU(tricore_env_get_cpu(env));
     /* in case we come from a helper-call we need to restore the PC */
-    cpu_restore_state(cs, pc);
+    cpu_restore_state(cs, pc, true);
 
     /* Tin is loaded into d[15] */
     env->gpr_d[15] = tin;

target/xtensa/op_helper.c

@@ -52,7 +52,7 @@ void xtensa_cpu_do_unaligned_access(CPUState *cs,
 
     if (xtensa_option_enabled(env->config, XTENSA_OPTION_UNALIGNED_EXCEPTION) &&
             !xtensa_option_enabled(env->config, XTENSA_OPTION_HW_ALIGNMENT)) {
-        cpu_restore_state(CPU(cpu), retaddr);
+        cpu_restore_state(CPU(cpu), retaddr, true);
         HELPER(exception_cause_vaddr)(env,
                 env->pc, LOAD_STORE_ALIGNMENT_CAUSE, addr);
     }
@@ -78,7 +78,7 @@ void tlb_fill(CPUState *cs, target_ulong vaddr, int size,
                      paddr & TARGET_PAGE_MASK,
                      access, mmu_idx, page_size);
     } else {
-        cpu_restore_state(cs, retaddr);
+        cpu_restore_state(cs, retaddr, true);
         HELPER(exception_cause_vaddr)(env, env->pc, ret, vaddr);
     }
 }