[Qemu-devel] [PATCH 0/4] Define default CPU at configure time

[Qemu-devel] [PATCH 0/4] Define default CPU at configure time

[Laurent Vivier]

This series of patch allows to set the default CPU used by linux-user qemu.

When qemu is used in a container as a binfmt interpreter we can't use the
environment variable QEMU_CPU to set the CPU id.

The two last patches allows to display the default CPU id when "-cpu ?" is
used. Only two archs are updated as examples : arm and m68k.


Laurent Vivier (4):
  linux-user: define default cpu model in configure instead of
    linux-user/main.c
  linux-user: specify the cpu model during configure
  linux-user,m68k: display default cpu
  linux-user,arm: display default cpu

 configure            | 23 +++++++++++++++++++++++
 linux-user/main.c    | 36 +-----------------------------------
 target-arm/helper.c  |  5 +++++
 target-m68k/helper.c |  5 +++++
 4 files changed, 34 insertions(+), 35 deletions(-)

-- 
1.8.1.2

[Qemu-devel] [PATCH 1/4] linux-user: define default cpu model in configure instead of linux-user/main.c

[Laurent Vivier]

From: Laurent Vivier <Laurent@Vivier.EU>

Signed-off-by: Laurent Vivier <Laurent@Vivier.EU>
---
 configure         | 14 ++++++++++++++
 linux-user/main.c | 36 +-----------------------------------
 2 files changed, 15 insertions(+), 35 deletions(-)

diff --git a/configure b/configure
index e989609..ef84abe 100755
--- a/configure
+++ b/configure
@@ -4214,6 +4214,7 @@ target_dir="$target"
 config_target_mak=$target_dir/config-target.mak
 target_name=`echo $target | cut -d '-' -f 1`
 target_bigendian="no"
+target_default_cpu="any"
 
 case "$target_name" in
   armeb|lm32|m68k|microblaze|mips|mipsn32|mips64|moxie|or32|ppc|ppcemb|ppc64|ppc64abi32|s390x|sh4eb|sparc|sparc64|sparc32plus|xtensaeb)
@@ -4261,9 +4262,11 @@ TARGET_ABI_DIR=""
 
 case "$target_name" in
   i386)
+    target_default_cpu="qemu32"
   ;;
   x86_64)
     TARGET_BASE_ARCH=i386
+    target_default_cpu="qemu64"
   ;;
   alpha)
   ;;
@@ -4287,17 +4290,20 @@ case "$target_name" in
   mips|mipsel)
     TARGET_ARCH=mips
     echo "TARGET_ABI_MIPSO32=y" >> $config_target_mak
+    target_default_cpu="24Kf"
   ;;
   mipsn32|mipsn32el)
     TARGET_ARCH=mips64
     TARGET_BASE_ARCH=mips
     echo "TARGET_ABI_MIPSN32=y" >> $config_target_mak
     echo "TARGET_ABI32=y" >> $config_target_mak
+    target_default_cpu="20Kc"
   ;;
   mips64|mips64el)
     TARGET_ARCH=mips64
     TARGET_BASE_ARCH=mips
     echo "TARGET_ABI_MIPSN64=y" >> $config_target_mak
+    target_default_cpu="20Kc"
   ;;
   moxie)
   ;;
@@ -4307,16 +4313,19 @@ case "$target_name" in
   ;;
   ppc)
     gdb_xml_files="power-core.xml power-fpu.xml power-altivec.xml power-spe.xml"
+    target_default_cpu="750"
   ;;
   ppcemb)
     TARGET_BASE_ARCH=ppc
     TARGET_ABI_DIR=ppc
     gdb_xml_files="power-core.xml power-fpu.xml power-altivec.xml power-spe.xml"
+    target_default_cpu="750"
   ;;
   ppc64)
     TARGET_BASE_ARCH=ppc
     TARGET_ABI_DIR=ppc
     gdb_xml_files="power64-core.xml power-fpu.xml power-altivec.xml power-spe.xml"
+    target_default_cpu="970fx"
   ;;
   ppc64abi32)
     TARGET_ARCH=ppc64
@@ -4324,21 +4333,25 @@ case "$target_name" in
     TARGET_ABI_DIR=ppc
     echo "TARGET_ABI32=y" >> $config_target_mak
     gdb_xml_files="power64-core.xml power-fpu.xml power-altivec.xml power-spe.xml"
+    target_default_cpu="750"
   ;;
   sh4|sh4eb)
     TARGET_ARCH=sh4
     bflt="yes"
   ;;
   sparc)
+    target_default_cpu="Fujitsu MB86904"
   ;;
   sparc64)
     TARGET_BASE_ARCH=sparc
+    target_default_cpu="TI UltraSparc II"
   ;;
   sparc32plus)
     TARGET_ARCH=sparc64
     TARGET_BASE_ARCH=sparc
     TARGET_ABI_DIR=sparc
     echo "TARGET_ABI32=y" >> $config_target_mak
+    target_default_cpu="TI UltraSparc II"
   ;;
   s390x)
   ;;
@@ -4362,6 +4375,7 @@ upper() {
     echo "$@"| LC_ALL=C tr '[a-z]' '[A-Z]'
 }
 
+echo "TARGET_DEFAULT_CPU=\"$target_default_cpu\"" >> $config_target_mak
 target_arch_name="`upper $TARGET_ARCH`"
 echo "TARGET_$target_arch_name=y" >> $config_target_mak
 echo "TARGET_NAME=$target_name" >> $config_target_mak
diff --git a/linux-user/main.c b/linux-user/main.c
index 5c2f7b2..4681349 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -3595,41 +3595,7 @@ int main(int argc, char **argv, char **envp)
     init_paths(interp_prefix);
 
     if (cpu_model == NULL) {
-#if defined(TARGET_I386)
-#ifdef TARGET_X86_64
-        cpu_model = "qemu64";
-#else
-        cpu_model = "qemu32";
-#endif
-#elif defined(TARGET_ARM)
-        cpu_model = "any";
-#elif defined(TARGET_UNICORE32)
-        cpu_model = "any";
-#elif defined(TARGET_M68K)
-        cpu_model = "any";
-#elif defined(TARGET_SPARC)
-#ifdef TARGET_SPARC64
-        cpu_model = "TI UltraSparc II";
-#else
-        cpu_model = "Fujitsu MB86904";
-#endif
-#elif defined(TARGET_MIPS)
-#if defined(TARGET_ABI_MIPSN32) || defined(TARGET_ABI_MIPSN64)
-        cpu_model = "20Kc";
-#else
-        cpu_model = "24Kf";
-#endif
-#elif defined TARGET_OPENRISC
-        cpu_model = "or1200";
-#elif defined(TARGET_PPC)
-#ifdef TARGET_PPC64
-        cpu_model = "970fx";
-#else
-        cpu_model = "750";
-#endif
-#else
-        cpu_model = "any";
-#endif
+        cpu_model = TARGET_DEFAULT_CPU;
     }
     tcg_exec_init(0);
     cpu_exec_init_all();
-- 
1.8.1.2

[Qemu-devel] [PATCH 2/4] linux-user: specify the cpu model during configure

[Laurent Vivier]

From: Laurent Vivier <Laurent@Vivier.EU>

This patch allows to set the default cpu model for a given architecture,
for instance:

 configure --target-list=m68k-linux-user --m68k-default-cpu=m68040

Signed-off-by: Laurent Vivier <Laurent@Vivier.EU>
---
 configure | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/configure b/configure
index ef84abe..22b27fc 100755
--- a/configure
+++ b/configure
@@ -650,6 +650,10 @@ for opt do
   ;;
   --target-list=*) target_list="$optarg"
   ;;
+  --*-default-cpu=*)
+    tmp=`expr "x$opt" : 'x--\(.*\)-default-cpu=.*'`
+    eval ${tmp}_default_cpu="\"$optarg\""
+  ;;
   --enable-trace-backend=*) trace_backend="$optarg"
   ;;
   --with-trace-file=*) trace_file="$optarg"
@@ -1025,6 +1029,7 @@ echo "                           use %M for cpu name [$interp_prefix]"
 echo "  --target-list=LIST       set target list (default: build everything)"
 echo "Available targets: $default_target_list" | \
     fold -s -w 53 | sed -e 's/^/                           /'
+echo "  --ARCH-default-cpu=CPU   set the default cpu for a given architecture"
 echo ""
 echo "Advanced options (experts only):"
 echo "  --source-path=PATH       path of source code [$source_path]"
@@ -4375,6 +4380,10 @@ upper() {
     echo "$@"| LC_ALL=C tr '[a-z]' '[A-Z]'
 }
 
+tmp_target_default_cpu=`eval echo \\$${target_name}_default_cpu`
+if [ "x$tmp_target_default_cpu" != "x" ] ; then
+  target_default_cpu="$tmp_target_default_cpu"
+fi
 echo "TARGET_DEFAULT_CPU=\"$target_default_cpu\"" >> $config_target_mak
 target_arch_name="`upper $TARGET_ARCH`"
 echo "TARGET_$target_arch_name=y" >> $config_target_mak
-- 
1.8.1.2

[Qemu-devel] [PATCH 3/4] linux-user,m68k: display default cpu

[Laurent Vivier]

From: Laurent Vivier <Laurent@Vivier.EU>

Signed-off-by: Laurent Vivier <Laurent@Vivier.EU>
---
 target-m68k/helper.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/target-m68k/helper.c b/target-m68k/helper.c
index 00a7a08..123329a 100644
--- a/target-m68k/helper.c
+++ b/target-m68k/helper.c
@@ -52,6 +52,11 @@ static void m68k_cpu_list_entry(gpointer data, gpointer user_data)
 
     typename = object_class_get_name(c);
     name = g_strndup(typename, strlen(typename) - strlen("-" TYPE_M68K_CPU));
+    if (strcmp(name, TARGET_DEFAULT_CPU) == 0) {
+        (*s->cpu_fprintf)(s->file, " >");
+    } else {
+        (*s->cpu_fprintf)(s->file, "  ");
+    }
     (*s->cpu_fprintf)(s->file, "%s\n",
                       name);
     g_free(name);
-- 
1.8.1.2

[Qemu-devel] [PATCH 4/4] linux-user,arm: display default cpu

[Laurent Vivier]

From: Laurent Vivier <Laurent@Vivier.EU>

Signed-off-by: Laurent Vivier <Laurent@Vivier.EU>
---
 target-arm/helper.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/target-arm/helper.c b/target-arm/helper.c
index e51ef20..26863d4 100644
--- a/target-arm/helper.c
+++ b/target-arm/helper.c
@@ -1809,6 +1809,11 @@ static void arm_cpu_list_entry(gpointer data, gpointer user_data)
 
     typename = object_class_get_name(oc);
     name = g_strndup(typename, strlen(typename) - strlen("-" TYPE_ARM_CPU));
+    if (strcmp(name, TARGET_DEFAULT_CPU) == 0) {
+        (*s->cpu_fprintf)(s->file, " >");
+    } else {
+        (*s->cpu_fprintf)(s->file, "  ");
+    }
     (*s->cpu_fprintf)(s->file, "  %s\n",
                       name);
     g_free(name);
-- 
1.8.1.2

Re: [Qemu-devel] [PATCH 0/4] Define default CPU at configure time

[Peter Maydell]

On 6 September 2013 21:47, Laurent Vivier <laurent@vivier.eu> wrote:
> This series of patch allows to set the default CPU used by linux-user qemu.
>
> When qemu is used in a container as a binfmt interpreter we can't use the
> environment variable QEMU_CPU to set the CPU id.

I definitely don't like this. We shouldn't be hardcoding this at
configure time. There doesn't seem to be any particular reason
why QEMU_CPU is the only option you might want to set for
your binfmt-interpreter either.

Is there a reason why using a wrapper script which sets
options to the real qemu binary won't work?

thanks
-- PMM

Re: [Qemu-devel] [PATCH 0/4] Define default CPU at configure time

[Laurent Vivier]

Le 07/09/2013 10:43, Peter Maydell a écrit :
> On 6 September 2013 21:47, Laurent Vivier <laurent@vivier.eu> wrote:
>> This series of patch allows to set the default CPU used by linux-user qemu.
>>
>> When qemu is used in a container as a binfmt interpreter we can't use the
>> environment variable QEMU_CPU to set the CPU id.
> I definitely don't like this. We shouldn't be hardcoding this at
> configure time. There doesn't seem to be any particular reason
> why QEMU_CPU is the only option you might want to set for
> your binfmt-interpreter either.
In fact, I don't understand why a given CPU id has been chosen to be the 
default value. I think there is a default value not because this is the 
best/most used value but because we need a default. It's hardcoded at 
development time. So I think this is better to be able to choose this 
default value without editing any file. A configuration option is the 
best solution for me. Moreover, this doesn't change the default behavior.
> Is there a reason why using a wrapper script which sets
> options to the real qemu binary won't work?
Personal reason : I don't like wrapper. Kernel must load two 
executables, wrapper must analyze environment, auxv, parameters and pass 
what it needs to pass.

But I don't want to push these patches at any reason : I just want to share.

Thank you for your comments.

Regards,
Laurent

Re: [Qemu-devel] [PATCH 0/4] Define default CPU at configure time

[Peter Maydell]

On 7 September 2013 10:13, Laurent Vivier <Laurent@vivier.eu> wrote:
> Le 07/09/2013 10:43, Peter Maydell a écrit :
> In fact, I don't understand why a given CPU id has been chosen to be the
> default value. I think there is a default value not because this is the
> best/most used value but because we need a default.

The default for ARM is "any", which is specifically for linux-user
and means "enable all possible user-visible instruction set options".
That means it should be able to run any guest binary OK.
Some other target CPU types do this, but not all; I think that
ideally we should convert them to do similarly.

I agree that the cases where we've picked some specific CPU
to be the linux-user default are a bit dubious.

-- PMM

Re: [Qemu-devel] [PATCH 0/4] Define default CPU at configure time

[Richard Henderson]

On 09/07/2013 02:19 AM, Peter Maydell wrote:
> On 7 September 2013 10:13, Laurent Vivier <Laurent@vivier.eu> wrote:
>> Le 07/09/2013 10:43, Peter Maydell a écrit :
>> In fact, I don't understand why a given CPU id has been chosen to be the
>> default value. I think there is a default value not because this is the
>> best/most used value but because we need a default.
> 
> The default for ARM is "any", which is specifically for linux-user
> and means "enable all possible user-visible instruction set options".
> That means it should be able to run any guest binary OK.
> Some other target CPU types do this, but not all; I think that
> ideally we should convert them to do similarly.

For mips this is impossible.  There are multiple isa extensions that are
mutually exclusive.  But for everyone else that ought to work.


r~

Re: [Qemu-devel] [PATCH 0/4] Define default CPU at configure time

[Laurent Vivier]

[-- Attachment #1: Type: text/plain, Size: 1064 bytes --]


> Le 9 septembre 2013 à 21:23, Richard Henderson <rth@twiddle.net> a écrit :
>
>
> On 09/07/2013 02:19 AM, Peter Maydell wrote:
> > On 7 September 2013 10:13, Laurent Vivier <Laurent@vivier.eu> wrote:
> >> Le 07/09/2013 10:43, Peter Maydell a écrit :
> >> In fact, I don't understand why a given CPU id has been chosen to be the
> >> default value. I think there is a default value not because this is the
> >> best/most used value but because we need a default.
> >
> > The default for ARM is "any", which is specifically for linux-user
> > and means "enable all possible user-visible instruction set options".
> > That means it should be able to run any guest binary OK.
> > Some other target CPU types do this, but not all; I think that
> > ideally we should convert them to do similarly.
>
> For mips this is impossible. There are multiple isa extensions that are
> mutually exclusive. But for everyone else that ought to work.

It doesn't work for m68k, too. It's why I need to define the default I want to
use...

Regards,
Laurent

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Re: [Qemu-devel] [PATCH 0/4] Define default CPU at configure time

[Peter Maydell]

On 10 September 2013 08:13, Laurent Vivier <laurent@vivier.eu> wrote:
>> Le 9 septembre 2013 à 21:23, Richard Henderson <rth@twiddle.net> a écrit :
>> For mips this is impossible. There are multiple isa extensions that are
>> mutually exclusive. But for everyone else that ought to work.
>
> It doesn't work for m68k, too. It's why I need to define the default I want
> to use...

Where the instruction set options conflict I really
don't think we should have a default selectable at
configure time. Having different people with different
qemu-m68k or qemu-mips being able to run or not run
different programs sounds very confusing. At least if
there's a command line option or a wrapper to set
environment then it's reasonably clear that the
config is different. Also if these different
variants are properly represented by different ELF
information you can then register several different
wrappers to handle different flavours of m68k
or mips binary correctly.

-- PMM