Merge remote-tracking branch 'remotes/stsquad/tags/pull-mttcg-fixups-for-rc2-280317-1' into staging

MTTCG regression fixes for rc2

# gpg: Signature made Tue 28 Mar 2017 10:54:38 BST
# gpg:                using RSA key 0xFBD0DB095A9E2A44
# gpg: Good signature from "Alex Bennée (Master Work Key) <alex.bennee@linaro.org>"
# Primary key fingerprint: 6685 AE99 E751 67BC AFC8  DF35 FBD0 DB09 5A9E 2A44

* remotes/stsquad/tags/pull-mttcg-fixups-for-rc2-280317-1:
  replay/replay.c: bump REPLAY_VERSION
  tcg: Add a new line after incompatibility warning
  ui/console: use exclusive mechanism directly
  ui/console: ensure do_safe_dpy_refresh holds BQL
  bsd-user: align use of mmap_lock to that of linux-user
  user-exec: handle synchronous signals from QEMU gracefully
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

bsd-user/mmap.c

@@ -24,8 +24,7 @@
 
 //#define DEBUG_MMAP
 
-#if defined(CONFIG_USE_NPTL)
-pthread_mutex_t mmap_mutex;
+static pthread_mutex_t mmap_mutex = PTHREAD_MUTEX_INITIALIZER;
 static int __thread mmap_lock_count;
 
 void mmap_lock(void)
@@ -62,16 +61,6 @@ void mmap_fork_end(int child)
     else
         pthread_mutex_unlock(&mmap_mutex);
 }
-#else
-/* We aren't threadsafe to start with, so no need to worry about locking.  */
-void mmap_lock(void)
-{
-}
-
-void mmap_unlock(void)
-{
-}
-#endif
 
 /* NOTE: all the constants are the HOST ones, but addresses are target. */
 int target_mprotect(abi_ulong start, abi_ulong len, int prot)

bsd-user/qemu.h

@@ -209,10 +209,8 @@ abi_long target_mremap(abi_ulong old_addr, abi_ulong old_size,
                        abi_ulong new_addr);
 int target_msync(abi_ulong start, abi_ulong len, int flags);
 extern unsigned long last_brk;
-#if defined(CONFIG_USE_NPTL)
 void mmap_fork_start(void);
 void mmap_fork_end(int child);
-#endif
 
 /* main.c */
 extern unsigned long x86_stack_size;

cpu-exec-common.c

@@ -35,7 +35,7 @@ void cpu_loop_exit_noexc(CPUState *cpu)
 #if defined(CONFIG_SOFTMMU)
 void cpu_reloading_memory_map(void)
 {
-    if (qemu_in_vcpu_thread()) {
+    if (qemu_in_vcpu_thread() && current_cpu->running) {
         /* The guest can in theory prolong the RCU critical section as long
          * as it feels like. The major problem with this is that because it
          * can do multiple reconfigurations of the memory map within the

cpus.c

@@ -209,7 +209,7 @@ void qemu_tcg_configure(QemuOpts *opts, Error **errp)
                 if (!check_tcg_memory_orders_compatible()) {
                     error_report("Guest expects a stronger memory ordering "
                                  "than the host provides");
-                    error_printf("This may cause strange/hard to debug errors");
+                    error_printf("This may cause strange/hard to debug errors\n");
                 }
                 mttcg_enabled = true;
             }

replay/replay.c

@@ -22,7 +22,7 @@
 
 /* Current version of the replay mechanism.
    Increase it when file format changes. */
-#define REPLAY_VERSION              0xe02005
+#define REPLAY_VERSION              0xe02006
 /* Size of replay log header */
 #define HEADER_SIZE                 (sizeof(uint32_t) + sizeof(uint64_t))
 

ui/console.c

@@ -1576,17 +1576,22 @@ bool dpy_gfx_check_format(QemuConsole *con,
 }
 
 /*
- * Safe DPY refresh for TCG guests. This runs when the TCG vCPUs are
- * quiescent so we can avoid races between dirty page tracking for
- * direct frame-buffer access by the guest.
+ * Safe DPY refresh for TCG guests. We use the exclusive mechanism to
+ * ensure the TCG vCPUs are quiescent so we can avoid races between
+ * dirty page tracking for direct frame-buffer access by the guest.
  *
  * This is a temporary stopgap until we've fixed the dirty tracking
  * races in display adapters.
  */
-static void do_safe_dpy_refresh(CPUState *cpu, run_on_cpu_data opaque)
+static void do_safe_dpy_refresh(DisplayChangeListener *dcl)
 {
-    DisplayChangeListener *dcl = opaque.host_ptr;
+    qemu_mutex_unlock_iothread();
+    start_exclusive();
+    qemu_mutex_lock_iothread();
     dcl->ops->dpy_refresh(dcl);
+    qemu_mutex_unlock_iothread();
+    end_exclusive();
+    qemu_mutex_lock_iothread();
 }
 
 static void dpy_refresh(DisplayState *s)
@@ -1596,8 +1601,7 @@ static void dpy_refresh(DisplayState *s)
     QLIST_FOREACH(dcl, &s->listeners, next) {
         if (dcl->ops->dpy_refresh) {
             if (tcg_enabled()) {
-                async_safe_run_on_cpu(first_cpu, do_safe_dpy_refresh,
-                                      RUN_ON_CPU_HOST_PTR(dcl));
+                do_safe_dpy_refresh(dcl);
             } else {
                 dcl->ops->dpy_refresh(dcl);
             }

user-exec.c

@@ -57,10 +57,23 @@ static void cpu_exit_tb_from_sighandler(CPUState *cpu, sigset_t *old_set)
 static inline int handle_cpu_signal(uintptr_t pc, unsigned long address,
                                     int is_write, sigset_t *old_set)
 {
-    CPUState *cpu;
+    CPUState *cpu = current_cpu;
     CPUClass *cc;
     int ret;
 
+    /* For synchronous signals we expect to be coming from the vCPU
+     * thread (so current_cpu should be valid) and either from running
+     * code or during translation which can fault as we cross pages.
+     *
+     * If neither is true then something has gone wrong and we should
+     * abort rather than try and restart the vCPU execution.
+     */
+    if (!cpu || !cpu->running) {
+        printf("qemu:%s received signal outside vCPU context @ pc=0x%"
+               PRIxPTR "\n",  __func__, pc);
+        abort();
+    }
+
 #if defined(DEBUG_SIGNAL)
     printf("qemu: SIGSEGV pc=0x%08lx address=%08lx w=%d oldset=0x%08lx\n",
            pc, address, is_write, *(unsigned long *)old_set);
@@ -83,7 +96,7 @@ static inline int handle_cpu_signal(uintptr_t pc, unsigned long address,
              * currently executing TB was modified and must be exited
              * immediately.
              */
-            cpu_exit_tb_from_sighandler(current_cpu, old_set);
+            cpu_exit_tb_from_sighandler(cpu, old_set);
             g_assert_not_reached();
         default:
             g_assert_not_reached();
@@ -94,7 +107,6 @@ static inline int handle_cpu_signal(uintptr_t pc, unsigned long address,
        are still valid segv ones */
     address = h2g_nocheck(address);
 
-    cpu = current_cpu;
     cc = CPU_GET_CLASS(cpu);
     /* see if it is an MMU fault */
     g_assert(cc->handle_mmu_fault);