On Fri, 2 Sep 2011, Anthony Liguori wrote:
> Hi,
>
> There have been a few attempts in the past to allow TCG to be disabled
> at build time. Recently, Alex made the suggestion that we could do it by
> using
> the same trick that we used to introduce kvm support. That involves
> introducing
> a tcg_enabled() macro that will be (0) if TCG is disabled in the build.
>
> GCC is smart enough to do dead code elimination if it sees an if (0) and the
> result is that if you can do:
>
> if (tcg_enabled()) {
> foo();
> }
>
> and it's more or less equivalent to:
>
> #ifdef CONFIG_TCG
> foo();
> #endif
>
> Without the ugliness that comes from using the preprocessor. I think this
> ended
> up being pretty straight forward. exec.c could use a fair bit of cleanup but
> other than that, this pretty much eliminates all of the TCG code from the
> build.
>
> This absolutely is going to break non-x86 KVM builds if they use the
> --disable-tcg flag as I haven't tested those yet. The normal TCG build
> shouldn't be affected at all though.
>
> In principle, the code assumes that you need KVM if you don't have TCG. Of
> course, some extra logic could be added to allow for Xen if TCG isn't present.
I like the goal if the series very much and compilation with
--disable-tcg --enable-xen works out of the box!
However there are two problems:
- compilation with --disable-kvm --disable-xen (--enable-tcg) breaks on
my box, log attached;
- the automatic filtering on the target list introduced by the first
patch effectively prevents users from enabling xen with --disable-tcg,
unless they also enable kvm. See appended patch.
diff --git a/configure b/configure
index 3f2cf6a..64f85b6 100755
--- a/configure
+++ b/configure
@@ -3148,7 +3148,7 @@ if test "$static" = "no" -a "$user_pie" = "yes" ; then
echo "QEMU_CFLAGS+=-fpie" > libdis-user/config.mak
fi
-kvm_incompatible() {
+virt_incompatible() {
if test "$kvm" = "yes" -a \
\( "$1" = "$cpu" -o \
\( "$1" = "ppcemb" -a "$cpu" = "ppc" \) -o \
@@ -3158,9 +3158,14 @@ kvm_incompatible() {
\( "$1" = "x86_64" -a "$cpu" = "i386" \) -o \
\( "$1" = "i386" -a "$cpu" = "x86_64" \) \) ; then
return 1
- else
- return 0
fi
+ if test "$xen" = "yes" -a \
+ \( "$1" = "$cpu" -o \
+ \( "$1" = "x86_64" -a "$cpu" = "i386" \) -o \
+ \( "$1" = "i386" -a "$cpu" = "x86_64" \) \) ; then
+ return 1
+ fi
+ return 0
}
target_list2=
@@ -3219,7 +3224,7 @@ if test "$tcg" = "no"; then
if test "$target_softmmu" = "no"; then
continue;
fi
- if kvm_incompatible "$target_arch2"; then
+ if virt_incompatible "$target_arch2"; then
continue;
fi
fisstabellini@dt02:/local/scratch/sstabellini/qemu$ ./configure --disable-kvm
--disable-xen --target-list=i386-softmmu
Install prefix /usr/local
BIOS directory /usr/local/share/qemu
binary directory /usr/local/bin
library directory /usr/local/lib
include directory /usr/local/include
config directory /usr/local/etc
Manual directory /usr/local/share/man
ELF interp prefix /usr/gnemul/qemu-%M
Source path /local/scratch/sstabellini/qemu
C compiler gcc
Host C compiler gcc
CFLAGS -O2 -g
QEMU_CFLAGS -Werror -m64 -D_FORTIFY_SOURCE=2 -D_GNU_SOURCE
-D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -Wstrict-prototypes
-Wredundant-decls -Wall -Wundef -Wwrite-strings -Wmissing-prototypes
-fno-strict-aliasing -fstack-protector-all -Wendif-labels
-Wmissing-include-dirs -Wempty-body -Wnested-externs -Wformat-security
-Wformat-y2k -Winit-self -Wignored-qualifiers -Wold-style-declaration
-Wold-style-definition -Wtype-limits -I/usr/include/libpng12
-I/usr/local/include/spice-server -I/usr/local/include/pixman-1
-I/usr/local/include -I/usr/local/include/spice-1
LDFLAGS -Wl,--warn-common -m64 -g
make make
install install
python python
smbd /usr/sbin/smbd
host CPU x86_64
host big endian no
target list i386-softmmu
tcg debug enabled no
Mon debug enabled no
gprof enabled no
sparse enabled no
strip binaries yes
profiler no
static build no
-Werror enabled yes
SDL support yes
curses support yes
curl support no
check support no
mingw32 support no
Audio drivers oss
Extra audio cards ac97 es1370 sb16 hda
Block whitelist
Mixer emulation no
VNC support yes
VNC TLS support no
VNC SASL support no
VNC JPEG support yes
VNC PNG support yes
VNC thread no
xen support no
brlapi support no
bluez support no
Documentation yes
NPTL support yes
GUEST_BASE yes
PIE user targets no
vde support no
Linux AIO support yes
ATTR/XATTR support no
Install blobs yes
KVM support no
fdt support no
preadv support yes
fdatasync yes
madvise yes
posix_madvise yes
uuid support yes
vhost-net support yes
Trace backend nop
Trace output file trace-<pid>
spice support yes
rbd support no
xfsctl support no
nss used no
usb net redir no
OpenGL support yes
build guest agent yes
sstabellini@dt02:/local/scratch/sstabellini/qemu$ make -j12
GEN config-host.h
GEN trace.h
GEN qemu-options.def
GEN qapi-generated/qga-qapi-visit.h
GEN trace.c
CC trace/control.o
CC trace/default.o
GEN qemu-img-cmds.h
GEN qapi-generated/qga-qapi-types.h
GEN qapi-generated/qga-qmp-marshal.c
CC qemu-ga.o
CC qga/guest-agent-commands.o
CC qga/guest-agent-command-state.o
CC qemu-tool.o
CC qemu-error.o
CC trace/default.o
CC trace/control.o
CC qint.o
CC qstring.o
CC qdict.o
CC qlist.o
CC qfloat.o
CC qjson.o
CC qbool.o
CC json-lexer.o
CC json-streamer.o
CC json-parser.o
CC qerror.o
CC error.o
CC qemu-nbd.o
CC qemu-thread-posix.o
CC cache-utils.o
CC async.o
CC nbd.o
CC block.o
CC aio.o
CC aes.o
CC qemu-config.o
CC qemu-progress.o
CC qemu-coroutine.o
CC qemu-coroutine-lock.o
CC coroutine-ucontext.o
CC posix-aio-compat.o
CC linux-aio.o
CC block/raw.o
CC block/cow.o
CC block/qcow.o
CC block/vdi.o
CC block/vmdk.o
CC block/cloop.o
CC block/dmg.o
CC block/bochs.o
CC block/vpc.o
CC block/vvfat.o
CC block/qcow2.o
CC block/qcow2-refcount.o
CC block/qcow2-cluster.o
CC block/qcow2-snapshot.o
CC block/qcow2-cache.o
CC block/qed.o
CC block/qed-gencb.o
CC block/qed-l2-cache.o
CC block/qed-table.o
CC block/qed-cluster.o
CC block/qed-check.o
CC block/parallels.o
CC block/nbd.o
CC block/blkdebug.o
CC block/sheepdog.o
CC block/blkverify.o
CC block/raw-posix.o
CC qemu-timer-common.o
CC qemu-img.o
CC qemu-io.o
CC cmd.o
CC libhw64/vl.o
CC blockdev.o
CC libhw64/loader.o
CC libhw64/virtio-console.o
CC libhw64/usb-libhw.o
CC net.o
CC net/queue.o
CC net/checksum.o
CC libhw64/virtio-pci.o
CC libhw64/fw_cfg.o
CC net/util.o
CC net/socket.o
CC net/dump.o
CC net/tap.o
CC net/tap-linux.o
CC net/slirp.o
CC readline.o
CC console.o
CC cursor.o
CC libhw64/pci.o
CC os-posix.o
CC tcg-runtime.o
CC host-utils.o
CC irq.o
CC ioport.o
CC libhw64/pci_bridge.o
CC input.o
CC libhw64/msix.o
CC i2c.o
CC smbus.o
CC smbus_eeprom.o
CC eeprom93xx.o
CC scsi-disk.o
CC cdrom.o
CC scsi-generic.o
CC libhw64/msi.o
CC scsi-bus.o
CC hid.o
CC usb.o
CC usb-hub.o
CC usb-linux.o
CC libhw64/pci_host.o
CC libhw64/pcie_host.o
CC usb-hid.o
CC usb-msd.o
CC libhw64/ioh3420.o
CC usb-wacom.o
CC usb-serial.o
CC libhw64/xio3130_upstream.o
CC libhw64/xio3130_downstream.o
CC usb-net.o
CC libhw64/watchdog.o
CC usb-bus.o
CC libhw64/serial.o
CC usb-desc.o
CC bt.o
CC bt-host.o
CC libhw64/parallel.o
CC bt-vhci.o
CC libhw64/i8254.o
CC bt-l2cap.o
CC libhw64/pcspk.o
CC bt-sdp.o
CC bt-hci.o
CC bt-hid.o
CC usb-bt.o
CC bt-hci-csr.o
CC buffered_file.o
CC libhw64/pckbd.o
CC libhw64/usb-uhci.o
CC libhw64/usb-ohci.o
CC migration.o
CC libhw64/usb-ehci.o
CC migration-tcp.o
CC qemu-char.o
CC savevm.o
CC msmouse.o
CC ps2.o
CC qdev.o
CC libhw64/fdc.o
CC qdev-properties.o
CC block-migration.o
CC iohandler.o
CC libhw64/acpi.o
CC pflib.o
CC bitmap.o
CC bitops.o
CC libhw64/acpi_piix4.o
CC migration-exec.o
CC migration-unix.o
CC migration-fd.o
CC libhw64/pm_smbus.o
CC libhw64/apm.o
CC ui/spice-core.o
CC ui/spice-input.o
CC ui/spice-display.o
CC spice-qemu-char.o
CC libhw64/dma.o
CC audio/audio.o
CC audio/noaudio.o
CC audio/wavaudio.o
CC libhw64/hpet.o
CC libhw64/applesmc.o
CC libhw64/usb-ccid.o
CC audio/mixeng.o
CC audio/sdlaudio.o
CC audio/ossaudio.o
CC audio/spiceaudio.o
CC libhw64/ccid-card-passthru.o
CC audio/wavcapture.o
CC libhw64/wdt_i6300esb.o
CC ui/keymaps.o
CC libhw64/pcie.o
CC libhw64/pcie_aer.o
CC ui/sdl.o
CC ui/sdl_zoom.o
CC ui/x_keymap.o
CC libhw64/pcie_port.o
CC libhw64/ne2000.o
CC ui/curses.o
CC libhw64/eepro100.o
CC ui/vnc.o
CC ui/d3des.o
CC ui/vnc-enc-zlib.o
CC libhw64/pcnet-pci.o
CC ui/vnc-enc-hextile.o
CC libhw64/pcnet.o
CC ui/vnc-enc-tight.o
CC ui/vnc-palette.o
CC libhw64/e1000.o
CC ui/vnc-enc-zrle.o
CC libhw64/rtl8139.o
CC libhw64/ne2000-isa.o
CC ui/vnc-jobs-sync.o
CC libhw64/ide/core.o
CC iov.o
CC libhw64/ide/atapi.o
CC acl.o
CC libhw64/ide/qdev.o
CC compatfd.o
CC notify.o
CC libhw64/ide/pci.o
CC event_notifier.o
CC libhw64/ide/isa.o
CC qemu-timer.o
CC slirp/cksum.o
CC libhw64/ide/piix.o
CC slirp/if.o
CC libhw64/ide/ahci.o
CC libhw64/ide/ich.o
CC libhw64/lsi53c895a.o
CC libhw64/dma-helpers.o
CC slirp/ip_icmp.o
CC slirp/ip_input.o
CC slirp/ip_output.o
CC libhw64/sysbus.o
CC slirp/slirp.o
CC libhw64/isa-bus.o
CC libhw64/qdev-addr.o
CC libhw64/vga-pci.o
CC slirp/mbuf.o
CC slirp/misc.o
CC slirp/sbuf.o
CC slirp/socket.o
CC libhw64/vga-isa.o
CC libhw64/vmware_vga.o
CC libhw64/vmmouse.o
CC libhw64/sb16.o
CC slirp/tcp_input.o
CC libhw64/es1370.o
CC slirp/tcp_output.o
CC slirp/tcp_subr.o
CC libhw64/ac97.o
CC slirp/tcp_timer.o
CC libhw64/intel-hda.o
CC slirp/udp.o
CC slirp/bootp.o
CC slirp/tftp.o
CC libhw64/hda-audio.o
CC slirp/arp_table.o
AS optionrom/multiboot.o
AS optionrom/linuxboot.o
CC libdis/i386-dis.o
Building optionrom/multiboot.img
Building optionrom/multiboot.raw
Building optionrom/linuxboot.img
CC qemu-error.o
Signing optionrom/multiboot.bin
CC qemu-sockets.o
Building optionrom/linuxboot.raw
Signing optionrom/linuxboot.bin
CC module.o
CC qemu-option.o
CC cutils.o
CC osdep.o
CC oslib-posix.o
CC qapi/qapi-visit-core.o
CC qapi/qmp-input-visitor.o
CC qapi/qmp-output-visitor.o
CC qapi/qapi-dealloc-visitor.o
CC qapi/qmp-registry.o
CC qapi/qmp-dispatch.o
CC trace.o
CC qapi-generated/qga-qapi-visit.o
CC qapi-generated/qga-qapi-types.o
CC qapi-generated/qga-qmp-marshal.o
LINK qemu-nbd
LINK qemu-io
LINK qemu-img
LINK qemu-ga
GEN config-target.h
GEN i386-softmmu/hmp-commands.h
GEN i386-softmmu/qmp-commands.h
CC i386-softmmu/arch_init.o
CC i386-softmmu/cpus.o
CC i386-softmmu/machine.o
CC i386-softmmu/gdbstub.o
CC i386-softmmu/balloon.o
CC i386-softmmu/virtio.o
CC i386-softmmu/virtio-blk.o
CC i386-softmmu/virtio-balloon.o
CC i386-softmmu/virtio-net.o
CC i386-softmmu/virtio-serial-bus.o
CC i386-softmmu/vhost_net.o
CC i386-softmmu/rwhandler.o
CC i386-softmmu/kvm-stub.o
CC i386-softmmu/memory.o
CC i386-softmmu/xen-stub.o
CC i386-softmmu/exec.o
CC i386-softmmu/helper.o
CC i386-softmmu/cpuid.o
CC i386-softmmu/disas.o
CC i386-softmmu/vga.o
CC i386-softmmu/mc146818rtc.o
CC i386-softmmu/i8259.o
CC i386-softmmu/pc.o
CC i386-softmmu/cirrus_vga.o
CC i386-softmmu/sga.o
CC i386-softmmu/apic.o
CC i386-softmmu/ioapic.o
CC i386-softmmu/piix_pci.o
CC i386-softmmu/vmport.o
rm multiboot.o linuxboot.raw linuxboot.img multiboot.raw multiboot.img
linuxboot.o
CC i386-softmmu/device-hotplug.o
CC i386-softmmu/pci-hotplug.o
CC i386-softmmu/smbios.o
CC i386-softmmu/wdt_ib700.o
CC i386-softmmu/debugcon.o
CC i386-softmmu/multiboot.o
CC i386-softmmu/pc_piix.o
CC i386-softmmu/qxl.o
CC i386-softmmu/qxl-logger.o
CC i386-softmmu/qxl-render.o
CC i386-softmmu/monitor.o
LINK i386-softmmu/qemu-system-i386
cpus.o: In function `tcg_cpu_exec':
/local/scratch/sstabellini/qemu/cpus.c:919: undefined reference to
`cpu_x86_exec'
exec.o: In function `tb_phys_invalidate':
/local/scratch/sstabellini/qemu/exec.c:912: undefined reference to
`tb_invalidated_flag'
/local/scratch/sstabellini/qemu/exec.c:912: undefined reference to
`tb_invalidated_flag'
exec.o: In function `tcg_exec_init':
/local/scratch/sstabellini/qemu/exec.c:585: undefined reference to
`cpu_gen_init'
/local/scratch/sstabellini/qemu/exec.c:592: undefined reference to `tcg_ctx'
exec.o: In function `tb_gen_code':
/local/scratch/sstabellini/qemu/exec.c:1016: undefined reference to
`tb_invalidated_flag'
/local/scratch/sstabellini/qemu/exec.c:1026: undefined reference to
`cpu_x86_gen_code'
exec.o: In function `cpu_io_recompile':
/local/scratch/sstabellini/qemu/exec.c:4695: undefined reference to
`cpu_restore_state'
exec.o: In function `slow_ldq_cmmu':
/local/scratch/sstabellini/qemu/softmmu_template.h:186: undefined reference to
`tlb_fill'
exec.o: In function `__ldq_cmmu':
/local/scratch/sstabellini/qemu/softmmu_template.h:135: undefined reference to
`tlb_fill'
exec.o: In function `slow_ldb_cmmu':
/local/scratch/sstabellini/qemu/softmmu_template.h:186: undefined reference to
`tlb_fill'
exec.o: In function `__ldb_cmmu':
/local/scratch/sstabellini/qemu/softmmu_template.h:135: undefined reference to
`tlb_fill'
exec.o: In function `slow_ldw_cmmu':
/local/scratch/sstabellini/qemu/softmmu_template.h:186: undefined reference to
`tlb_fill'
exec.o:/local/scratch/sstabellini/qemu/softmmu_template.h:135: more undefined
references to `tlb_fill' follow
exec.o: In function `tb_invalidate_phys_page_range':
/local/scratch/sstabellini/qemu/exec.c:1109: undefined reference to
`cpu_restore_state'
exec.o: In function `check_watchpoint':
/local/scratch/sstabellini/qemu/exec.c:3450: undefined reference to
`cpu_restore_state'
/local/scratch/sstabellini/qemu/exec.c:3460: undefined reference to
`cpu_resume_from_signal'
exec.o: In function `dump_exec_info':
/local/scratch/sstabellini/qemu/exec.c:4794: undefined reference to
`tcg_dump_info'
exec.o: In function `tcg_exec_init':
/local/scratch/sstabellini/qemu/exec.c:592: undefined reference to
`tcg_prologue_init'
exec.o: In function `cpu_io_recompile':
/local/scratch/sstabellini/qemu/exec.c:4738: undefined reference to
`cpu_resume_from_signal'
exec.o: In function `tb_invalidate_phys_page_range':
/local/scratch/sstabellini/qemu/exec.c:1147: undefined reference to
`cpu_resume_from_signal'
helper.o: In function `breakpoint_handler':
/local/scratch/sstabellini/qemu/target-i386/helper.c:1058: undefined reference
to `cpu_resume_from_signal'
/local/scratch/sstabellini/qemu/target-i386/helper.c:1065: undefined reference
to `raise_exception_env'
helper.o: In function `cpu_x86_init':
/local/scratch/sstabellini/qemu/target-i386/helper.c:1267: undefined reference
to `optimize_flags_init'
/local/scratch/sstabellini/qemu/target-i386/helper.c:1270: undefined reference
to `cpu_set_debug_excp_handler'
collect2: ld returned 1 exit status
make[1]: *** [qemu-system-i386] Error 1
make: *** [subdir-i386-softmmu] Error 2
sstabellini@dt02:/local/scratch/sstabellini/qemu$
