[Qemu-devel] [PATCH v6 19/19] tcg: enable MTTCG by default for ARM on x86 hosts

[Alex Bennée]

This enables the multi-threaded system emulation by default for ARMv7
and ARMv8 guests using the x86_64 TCG backend. This means:

  - The x86_64 TCG backend supports cmpxchg based atomic ops
  - The x86_64 TCG backend emits barriers for barrier ops

And on the guest side:

  - The ARM translate.c/translate-64.c have been converted to
    - use MTTCG safe atomic primitives
    - emit the appropriate barrier ops
  - The ARM machine has been updated to
    - hold the BQL when modifying shared cross-vCPU state
    - defer cpu_reset to async safe work

Signed-off-by: Alex Bennée <address@hidden>
---
 configure                       | 12 ++++++++++++
 default-configs/arm-softmmu.mak |  2 ++
 2 files changed, 14 insertions(+)

diff --git a/configure b/configure
index fd6f898..685eb03 100755
--- a/configure
+++ b/configure
@@ -516,6 +516,7 @@ else
 fi
 
 ARCH=
+host_mttcg_support=
 # Normalise host CPU name and set ARCH.
 # Note that this case should only have supported host CPUs, not guests.
 case "$cpu" in
@@ -527,6 +528,7 @@ case "$cpu" in
   ;;
   x86_64|amd64)
     cpu="x86_64"
+    host_mttcg_support=yes
   ;;
   armv*b|armv*l|arm)
     cpu="arm"
@@ -5703,6 +5705,10 @@ if test "$pthread_setname_np" = "yes" ; then
   echo "CONFIG_PTHREAD_SETNAME_NP=y" >> $config_host_mak
 fi
 
+if test "$host_mttcg_support" = "yes" ; then
+  echo "CONFIG_MTTCG_HOST=y" >> $config_host_mak
+fi
+
 if test "$tcg_interpreter" = "yes"; then
   QEMU_INCLUDES="-I\$(SRC_PATH)/tcg/tci $QEMU_INCLUDES"
 elif test "$ARCH" = "sparc64" ; then
@@ -5815,6 +5821,7 @@ target_dir="$target"
 config_target_mak=$target_dir/config-target.mak
 target_name=$(echo $target | cut -d '-' -f 1)
 target_bigendian="no"
+target_mttcg_support="no"
 
 case "$target_name" in
   
armeb|lm32|m68k|microblaze|mips|mipsn32|mips64|moxie|or32|ppc|ppcemb|ppc64|ppc64abi32|s390x|sh4eb|sparc|sparc64|sparc32plus|xtensaeb)
@@ -5872,11 +5879,13 @@ case "$target_name" in
     TARGET_ARCH=arm
     bflt="yes"
     gdb_xml_files="arm-core.xml arm-vfp.xml arm-vfp3.xml arm-neon.xml"
+    target_mttcg_support="yes"
   ;;
   aarch64)
     TARGET_BASE_ARCH=arm
     bflt="yes"
     gdb_xml_files="aarch64-core.xml aarch64-fpu.xml arm-core.xml arm-vfp.xml 
arm-vfp3.xml arm-neon.xml"
+    target_mttcg_support="yes"
   ;;
   cris)
   ;;
@@ -6027,6 +6036,9 @@ if test "$target_bigendian" = "yes" ; then
 fi
 if test "$target_softmmu" = "yes" ; then
   echo "CONFIG_SOFTMMU=y" >> $config_target_mak
+  if test "$target_mttcg_support" = "yes" ; then
+    echo "CONFIG_MTTCG_TARGET=y" >> $config_target_mak
+  fi
 fi
 if test "$target_user_only" = "yes" ; then
   echo "CONFIG_USER_ONLY=y" >> $config_target_mak
diff --git a/default-configs/arm-softmmu.mak b/default-configs/arm-softmmu.mak
index 6de3e16..007f751 100644
--- a/default-configs/arm-softmmu.mak
+++ b/default-configs/arm-softmmu.mak
@@ -115,3 +115,5 @@ CONFIG_ACPI=y
 CONFIG_SMBIOS=y
 CONFIG_ASPEED_SOC=y
 CONFIG_GPIO_KEY=y
+
+CONFIG_MTTCG_TARGET=y
-- 
2.10.1