Merge remote-tracking branch 'remotes/bonzini/tags/for-upstream' into staging

Miscellaneous bugfixes

# gpg: Signature made Wed 15 Nov 2017 15:27:25 GMT
# gpg:                using RSA key 0xBFFBD25F78C7AE83
# gpg: Good signature from "Paolo Bonzini <bonzini@gnu.org>"
# gpg:                 aka "Paolo Bonzini <pbonzini@redhat.com>"
# Primary key fingerprint: 46F5 9FBD 57D6 12E7 BFD4  E2F7 7E15 100C CD36 69B1
#      Subkey fingerprint: F133 3857 4B66 2389 866C  7682 BFFB D25F 78C7 AE83

* remotes/bonzini/tags/for-upstream:
  fix scripts/update-linux-headers.sh here document
  exec: Do not resolve subpage in mru_section
  util/stats64: Fix min/max comparisons
  cpu-exec: avoid cpu_exec_nocache infinite loop with record/replay
  cpu-exec: don't overwrite exception_index
  vhost-user-scsi: add missing virtqueue_size param
  target-i386: adds PV_TLB_FLUSH CPUID feature bit
  thread-posix: fix qemu_rec_mutex_trylock macro
  Makefile: simpler/faster "make help"
  ioapic/tracing: Remove last DPRINTFs
  Enable 8-byte wide MMIO for 16550 serial devices

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

1 files changed, 57 insertions, 42 deletions

diff --git a/accel/tcg/cpu-exec.c b/accel/tcg/cpu-exec.c
index 61297f8..f3de96f 100644
--- a/accel/tcg/cpu-exec.c
+++ b/accel/tcg/cpu-exec.c
@@ -470,48 +470,51 @@ static inline void cpu_handle_debug_exception(CPUState *cpu)
 
 static inline bool cpu_handle_exception(CPUState *cpu, int *ret)
 {
-    if (cpu->exception_index >= 0) {
-        if (cpu->exception_index >= EXCP_INTERRUPT) {
-            /* exit request from the cpu execution loop */
-            *ret = cpu->exception_index;
-            if (*ret == EXCP_DEBUG) {
-                cpu_handle_debug_exception(cpu);
-            }
-            cpu->exception_index = -1;
-            return true;
-        } else {
+    if (cpu->exception_index < 0) {
+#ifndef CONFIG_USER_ONLY
+        if (replay_has_exception()
+               && cpu->icount_decr.u16.low + cpu->icount_extra == 0) {
+            /* try to cause an exception pending in the log */
+            cpu_exec_nocache(cpu, 1, tb_find(cpu, NULL, 0, curr_cflags()), true);
+        }
+#endif
+        if (cpu->exception_index < 0) {
+            return false;
+        }
+    }
+
+    if (cpu->exception_index >= EXCP_INTERRUPT) {
+        /* exit request from the cpu execution loop */
+        *ret = cpu->exception_index;
+        if (*ret == EXCP_DEBUG) {
+            cpu_handle_debug_exception(cpu);
+        }
+        cpu->exception_index = -1;
+        return true;
+    } else {
 #if defined(CONFIG_USER_ONLY)
-            /* if user mode only, we simulate a fake exception
-               which will be handled outside the cpu execution
-               loop */
+        /* if user mode only, we simulate a fake exception
+           which will be handled outside the cpu execution
+           loop */
 #if defined(TARGET_I386)
+        CPUClass *cc = CPU_GET_CLASS(cpu);
+        cc->do_interrupt(cpu);
+#endif
+        *ret = cpu->exception_index;
+        cpu->exception_index = -1;
+        return true;
+#else
+        if (replay_exception()) {
             CPUClass *cc = CPU_GET_CLASS(cpu);
+            qemu_mutex_lock_iothread();
             cc->do_interrupt(cpu);
-#endif
-            *ret = cpu->exception_index;
+            qemu_mutex_unlock_iothread();
             cpu->exception_index = -1;
+        } else if (!replay_has_interrupt()) {
+            /* give a chance to iothread in replay mode */
+            *ret = EXCP_INTERRUPT;
             return true;
-#else
-            if (replay_exception()) {
-                CPUClass *cc = CPU_GET_CLASS(cpu);
-                qemu_mutex_lock_iothread();
-                cc->do_interrupt(cpu);
-                qemu_mutex_unlock_iothread();
-                cpu->exception_index = -1;
-            } else if (!replay_has_interrupt()) {
-                /* give a chance to iothread in replay mode */
-                *ret = EXCP_INTERRUPT;
-                return true;
-            }
-#endif
         }
-#ifndef CONFIG_USER_ONLY
-    } else if (replay_has_exception()
-               && cpu->icount_decr.u16.low + cpu->icount_extra == 0) {
-        /* try to cause an exception pending in the log */
-        cpu_exec_nocache(cpu, 1, tb_find(cpu, NULL, 0, curr_cflags()), true);
-        *ret = -1;
-        return true;
 #endif
     }
 
@@ -522,6 +525,19 @@ static inline bool cpu_handle_interrupt(CPUState *cpu,
                                         TranslationBlock **last_tb)
 {
     CPUClass *cc = CPU_GET_CLASS(cpu);
+    int32_t insns_left;
+
+    /* Clear the interrupt flag now since we're processing
+     * cpu->interrupt_request and cpu->exit_request.
+     */
+    insns_left = atomic_read(&cpu->icount_decr.u32);
+    atomic_set(&cpu->icount_decr.u16.high, 0);
+    if (unlikely(insns_left < 0)) {
+        /* Ensure the zeroing of icount_decr comes before the next read
+         * of cpu->exit_request or cpu->interrupt_request.
+         */
+        smp_mb();
+    }
 
     if (unlikely(atomic_read(&cpu->interrupt_request))) {
         int interrupt_request;
@@ -594,7 +610,9 @@ static inline bool cpu_handle_interrupt(CPUState *cpu,
     if (unlikely(atomic_read(&cpu->exit_request)
         || (use_icount && cpu->icount_decr.u16.low + cpu->icount_extra == 0))) {
         atomic_set(&cpu->exit_request, 0);
-        cpu->exception_index = EXCP_INTERRUPT;
+        if (cpu->exception_index == -1) {
+            cpu->exception_index = EXCP_INTERRUPT;
+        }
         return true;
     }
 
@@ -618,17 +636,14 @@ static inline void cpu_loop_exec_tb(CPUState *cpu, TranslationBlock *tb,
 
     *last_tb = NULL;
     insns_left = atomic_read(&cpu->icount_decr.u32);
-    atomic_set(&cpu->icount_decr.u16.high, 0);
     if (insns_left < 0) {
         /* Something asked us to stop executing chained TBs; just
          * continue round the main loop. Whatever requested the exit
          * will also have set something else (eg exit_request or
-         * interrupt_request) which we will handle next time around
-         * the loop.  But we need to ensure the zeroing of icount_decr
-         * comes before the next read of cpu->exit_request
-         * or cpu->interrupt_request.
+         * interrupt_request) which will be handled by
+         * cpu_handle_interrupt.  cpu_handle_interrupt will also
+         * clear cpu->icount_decr.u16.high.
          */
-        smp_mb();
         return;
     }