[PATCH 0/3] semihosting: Restrict to TCG

[PATCH 0/3] semihosting: Restrict to TCG

[Philippe Mathieu-Daudé]

It is pointless to build semihosting when TCG is not available.

Philippe Mathieu-Daudé (3):
  target/mips: Restrict semihosting to TCG
  target/riscv: Restrict semihosting to TCG
  semihosting: Restrict to TCG

 semihosting/Kconfig  | 1 +
 target/mips/Kconfig  | 2 +-
 target/riscv/Kconfig | 4 ++--
 3 files changed, 4 insertions(+), 3 deletions(-)

-- 
2.41.0

[PATCH 1/3] target/mips: Restrict semihosting to TCG

[Philippe Mathieu-Daudé]

It is pointless to build semihosting when TCG is not available.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
---
 target/mips/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/target/mips/Kconfig b/target/mips/Kconfig
index eb19c94c7d..4918fa42e9 100644
--- a/target/mips/Kconfig
+++ b/target/mips/Kconfig
@@ -1,6 +1,6 @@
 config MIPS
     bool
-    select SEMIHOSTING
+    select SEMIHOSTING if TCG
 
 config MIPS64
     bool
-- 
2.41.0

[PATCH 2/3] target/riscv: Restrict semihosting to TCG

[Philippe Mathieu-Daudé]

It is pointless to build semihosting when TCG is not available.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
---
 target/riscv/Kconfig | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/target/riscv/Kconfig b/target/riscv/Kconfig
index 5f30df22f2..5c360a70a9 100644
--- a/target/riscv/Kconfig
+++ b/target/riscv/Kconfig
@@ -1,9 +1,9 @@
 config RISCV32
     bool
-    select ARM_COMPATIBLE_SEMIHOSTING # for do_common_semihosting()
+    select ARM_COMPATIBLE_SEMIHOSTING if TCG # for do_common_semihosting()
     select DEVICE_TREE # needed by boot.c
 
 config RISCV64
     bool
-    select ARM_COMPATIBLE_SEMIHOSTING # for do_common_semihosting()
+    select ARM_COMPATIBLE_SEMIHOSTING if TCG # for do_common_semihosting()
     select DEVICE_TREE # needed by boot.c
-- 
2.41.0

[PATCH 3/3] semihosting: Restrict to TCG

[Philippe Mathieu-Daudé]

It is pointless to build semihosting when TCG is not available.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
---
 semihosting/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/semihosting/Kconfig b/semihosting/Kconfig
index eaf3a20ef5..fbe6ac87f9 100644
--- a/semihosting/Kconfig
+++ b/semihosting/Kconfig
@@ -1,6 +1,7 @@
 
 config SEMIHOSTING
        bool
+       depends on TCG
 
 config ARM_COMPATIBLE_SEMIHOSTING
        bool
-- 
2.41.0

Re: [PATCH 3/3] semihosting: Restrict to TCG

[Paolo Bonzini]

On Wed, May 29, 2024 at 5:56 PM Philippe Mathieu-Daudé
<philmd@linaro.org> wrote:
> It is pointless to build semihosting when TCG is not available.

Why? I would have naively assumed that a suitable semihosting API
could be implemented by KVM. The justification (and thus the commit
message) needs to be different for each architecture if it's a matter
of instruction set or insufficient KVM userspace API.

Paolo

> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> ---
>  semihosting/Kconfig | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/semihosting/Kconfig b/semihosting/Kconfig
> index eaf3a20ef5..fbe6ac87f9 100644
> --- a/semihosting/Kconfig
> +++ b/semihosting/Kconfig
> @@ -1,6 +1,7 @@
>
>  config SEMIHOSTING
>         bool
> +       depends on TCG
>
>  config ARM_COMPATIBLE_SEMIHOSTING
>         bool
> --
> 2.41.0
>

Re: [PATCH 3/3] semihosting: Restrict to TCG

[Philippe Mathieu-Daudé]

On 30/5/24 08:02, Paolo Bonzini wrote:
> On Wed, May 29, 2024 at 5:56 PM Philippe Mathieu-Daudé
> <philmd@linaro.org> wrote:
>> It is pointless to build semihosting when TCG is not available.
> 
> Why? I would have naively assumed that a suitable semihosting API
> could be implemented by KVM. The justification (and thus the commit
> message) needs to be different for each architecture if it's a matter
> of instruction set or insufficient KVM userspace API.

I wasn't sure where semihosting could be used so asked on IRC and
Alex told me TCG only. Maybe the current implementation is TCG
only, and I can reword. It certainly need some refactor to work
on KVM, because currently semihosting end calling the TCG probe_access
API, which I'm trying to restrict to TCG in order to ease linking
multiple libtcg for the single binary (see
https://lore.kernel.org/qemu-devel/20240529155918.6221-1-philmd@linaro.org/).

> Paolo
> 
>> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
>> ---
>>   semihosting/Kconfig | 1 +
>>   1 file changed, 1 insertion(+)
>>
>> diff --git a/semihosting/Kconfig b/semihosting/Kconfig
>> index eaf3a20ef5..fbe6ac87f9 100644
>> --- a/semihosting/Kconfig
>> +++ b/semihosting/Kconfig
>> @@ -1,6 +1,7 @@
>>
>>   config SEMIHOSTING
>>          bool
>> +       depends on TCG
>>
>>   config ARM_COMPATIBLE_SEMIHOSTING
>>          bool
>> --
>> 2.41.0
>>
> 

Re: [PATCH 3/3] semihosting: Restrict to TCG

[Paolo Bonzini]

On Thu, May 30, 2024 at 9:22 AM Philippe Mathieu-Daudé
<philmd@linaro.org> wrote:
>
> On 30/5/24 08:02, Paolo Bonzini wrote:
> > On Wed, May 29, 2024 at 5:56 PM Philippe Mathieu-Daudé
> > <philmd@linaro.org> wrote:
> >> It is pointless to build semihosting when TCG is not available.
> >
> > Why? I would have naively assumed that a suitable semihosting API
> > could be implemented by KVM. The justification (and thus the commit
> > message) needs to be different for each architecture if it's a matter
> > of instruction set or insufficient KVM userspace API.
>
> I wasn't sure where semihosting could be used so asked on IRC and
> Alex told me TCG only. Maybe the current implementation is TCG
> only, and I can reword. It certainly need some refactor to work
> on KVM, because currently semihosting end calling the TCG probe_access
> API, which I'm trying to restrict to TCG in order to ease linking
> multiple libtcg for the single binary (see
> https://lore.kernel.org/qemu-devel/20240529155918.6221-1-philmd@linaro.org/).

Ok, that goes in the commit message though.

"Semihosting currently uses the TCG probe_access API. It is pointless
to have it in the binary when TCG isn't".

and in the first two patches:

"Semihosting currently uses the TCG probe_access API. To prepare for
encoding the TCG dependency in Kconfig, do not enable it unless TCG is
available".

But then, "select FOO if TCG" mean that it can be compiled out; so
perhaps "imply SEMIHOSTING if TCG" is better? Same for RISC-V's
"select ARM_COMPATIBLE_SEMIHOSTING if TCG".

Paolo

> > Paolo
> >
> >> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> >> ---
> >>   semihosting/Kconfig | 1 +
> >>   1 file changed, 1 insertion(+)
> >>
> >> diff --git a/semihosting/Kconfig b/semihosting/Kconfig
> >> index eaf3a20ef5..fbe6ac87f9 100644
> >> --- a/semihosting/Kconfig
> >> +++ b/semihosting/Kconfig
> >> @@ -1,6 +1,7 @@
> >>
> >>   config SEMIHOSTING
> >>          bool
> >> +       depends on TCG
> >>
> >>   config ARM_COMPATIBLE_SEMIHOSTING
> >>          bool
> >> --
> >> 2.41.0
> >>
> >
>

Re: [PATCH 3/3] semihosting: Restrict to TCG

[Philippe Mathieu-Daudé]

On 30/5/24 09:31, Paolo Bonzini wrote:
> On Thu, May 30, 2024 at 9:22 AM Philippe Mathieu-Daudé
> <philmd@linaro.org> wrote:
>>
>> On 30/5/24 08:02, Paolo Bonzini wrote:
>>> On Wed, May 29, 2024 at 5:56 PM Philippe Mathieu-Daudé
>>> <philmd@linaro.org> wrote:
>>>> It is pointless to build semihosting when TCG is not available.
>>>
>>> Why? I would have naively assumed that a suitable semihosting API
>>> could be implemented by KVM. The justification (and thus the commit
>>> message) needs to be different for each architecture if it's a matter
>>> of instruction set or insufficient KVM userspace API.
>>
>> I wasn't sure where semihosting could be used so asked on IRC and
>> Alex told me TCG only. Maybe the current implementation is TCG
>> only, and I can reword. It certainly need some refactor to work
>> on KVM, because currently semihosting end calling the TCG probe_access
>> API, which I'm trying to restrict to TCG in order to ease linking
>> multiple libtcg for the single binary (see
>> https://lore.kernel.org/qemu-devel/20240529155918.6221-1-philmd@linaro.org/).
> 
> Ok, that goes in the commit message though.
> 
> "Semihosting currently uses the TCG probe_access API. It is pointless
> to have it in the binary when TCG isn't".
> 
> and in the first two patches:
> 
> "Semihosting currently uses the TCG probe_access API. To prepare for
> encoding the TCG dependency in Kconfig, do not enable it unless TCG is
> available".
> 
> But then, "select FOO if TCG" mean that it can be compiled out; so
> perhaps "imply SEMIHOSTING if TCG" is better? Same for RISC-V's
> "select ARM_COMPATIBLE_SEMIHOSTING if TCG".

You are right. Thanks for reminding me Kconfig "imply" :)

Regards,

Phil.

Re: [PATCH 3/3] semihosting: Restrict to TCG

[Philippe Mathieu-Daudé]

Hi Paolo,

On 30/5/24 15:58, Philippe Mathieu-Daudé wrote:
> On 30/5/24 09:31, Paolo Bonzini wrote:
>> On Thu, May 30, 2024 at 9:22 AM Philippe Mathieu-Daudé
>> <philmd@linaro.org> wrote:
>>>
>>> On 30/5/24 08:02, Paolo Bonzini wrote:
>>>> On Wed, May 29, 2024 at 5:56 PM Philippe Mathieu-Daudé
>>>> <philmd@linaro.org> wrote:
>>>>> It is pointless to build semihosting when TCG is not available.
>>>>
>>>> Why? I would have naively assumed that a suitable semihosting API
>>>> could be implemented by KVM. The justification (and thus the commit
>>>> message) needs to be different for each architecture if it's a matter
>>>> of instruction set or insufficient KVM userspace API.
>>>
>>> I wasn't sure where semihosting could be used so asked on IRC and
>>> Alex told me TCG only. Maybe the current implementation is TCG
>>> only, and I can reword. It certainly need some refactor to work
>>> on KVM, because currently semihosting end calling the TCG probe_access
>>> API, which I'm trying to restrict to TCG in order to ease linking
>>> multiple libtcg for the single binary (see
>>> https://lore.kernel.org/qemu-devel/20240529155918.6221-1-philmd@linaro.org/).
>>
>> Ok, that goes in the commit message though.
>>
>> "Semihosting currently uses the TCG probe_access API. It is pointless
>> to have it in the binary when TCG isn't".
>>
>> and in the first two patches:
>>
>> "Semihosting currently uses the TCG probe_access API. To prepare for
>> encoding the TCG dependency in Kconfig, do not enable it unless TCG is
>> available".
>>
>> But then, "select FOO if TCG" mean that it can be compiled out; so
>> perhaps "imply SEMIHOSTING if TCG" is better? Same for RISC-V's
>> "select ARM_COMPATIBLE_SEMIHOSTING if TCG".

Building qemu-system-mips configured with --without-default-devices:

Undefined symbols for architecture arm64:
   "_qemu_semihosting_console_write", referenced from:
       _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
   "_semihost_sys_close", referenced from:
       _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
   "_uaccess_strlen_user", referenced from:
       _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
   ...

So this one has to use "select".

Similarly m68k:

Undefined symbols for architecture arm64:
   "_semihost_sys_close", referenced from:
       _do_m68k_semihosting in target_m68k_m68k-semi.c.o
   ...

I can link m68k using semihosting stubs but I'm not sure it is right:

-- >8 --
diff --git a/semihosting/stubs-target-all.c b/semihosting/stubs-target-all.c
new file mode 100644
index 0000000000..1f33173f43
--- /dev/null
+++ b/semihosting/stubs-target-all.c
@@ -0,0 +1,97 @@
+/*
+ * Semihosting Stubs
+ *
+ * Copyright (c) 2024 Linaro Ltd
+ *
+ * Stubs for semihosting targets that don't actually do semihosting.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "exec/exec-all.h"
+#include "semihosting/syscalls.h"
+
+void semihost_sys_open(CPUState *cs, gdb_syscall_complete_cb complete,
+                       target_ulong fname, target_ulong fname_len,
+                       int gdb_flags, int mode)
+{
+}
+
+void semihost_sys_close(CPUState *cs, gdb_syscall_complete_cb complete, 
int fd)
+{
+}
+
+void semihost_sys_read_gf(CPUState *cs, gdb_syscall_complete_cb complete,
+                          GuestFD *gf, target_ulong buf, target_ulong len)
+{
+}
+
+void semihost_sys_read(CPUState *cs, gdb_syscall_complete_cb complete,
+                       int fd, target_ulong buf, target_ulong len)
+{
+}
+
+void semihost_sys_write_gf(CPUState *cs, gdb_syscall_complete_cb complete,
+                           GuestFD *gf, target_ulong buf, target_ulong len)
+{
+}
+
+void semihost_sys_write(CPUState *cs, gdb_syscall_complete_cb complete,
+                        int fd, target_ulong buf, target_ulong len)
+{
+}
+
+void semihost_sys_lseek(CPUState *cs, gdb_syscall_complete_cb complete,
+                        int fd, int64_t off, int gdb_whence)
+{
+}
+
+void semihost_sys_isatty(CPUState *cs, gdb_syscall_complete_cb 
complete, int fd)
+{
+}
+
+void semihost_sys_flen(CPUState *cs, gdb_syscall_complete_cb fstat_cb,
+                       gdb_syscall_complete_cb flen_cb, int fd,
+                       target_ulong fstat_addr)
+{
+}
+
+void semihost_sys_fstat(CPUState *cs, gdb_syscall_complete_cb complete,
+                        int fd, target_ulong addr)
+{
+}
+
+void semihost_sys_stat(CPUState *cs, gdb_syscall_complete_cb complete,
+                       target_ulong fname, target_ulong fname_len,
+                       target_ulong addr)
+{
+}
+
+void semihost_sys_remove(CPUState *cs, gdb_syscall_complete_cb complete,
+                         target_ulong fname, target_ulong fname_len)
+{
+}
+
+void semihost_sys_rename(CPUState *cs, gdb_syscall_complete_cb complete,
+                         target_ulong oname, target_ulong oname_len,
+                         target_ulong nname, target_ulong nname_len)
+{
+}
+
+void semihost_sys_system(CPUState *cs, gdb_syscall_complete_cb complete,
+                         target_ulong cmd, target_ulong cmd_len)
+{
+}
+
+void semihost_sys_gettimeofday(CPUState *cs, gdb_syscall_complete_cb 
complete,
+                               target_ulong tv_addr, target_ulong tz_addr)
+{
+}
+
+#ifndef CONFIG_USER_ONLY
+void semihost_sys_poll_one(CPUState *cs, gdb_syscall_complete_cb complete,
+                           int fd, GIOCondition cond, int timeout)
+{
+}
+#endif
diff --git a/semihosting/meson.build b/semihosting/meson.build
index 34933e5a19..aa8b7a9913 100644
--- a/semihosting/meson.build
+++ b/semihosting/meson.build
@@ -7,7 +7,7 @@ specific_ss.add(when: ['CONFIG_SEMIHOSTING', 
'CONFIG_SYSTEM_ONLY'], if_true: fil
    'config.c',
    'console.c',
    'uaccess.c',
-))
+), if_false: files('stubs-target-all.c'))

  common_ss.add(when: ['CONFIG_SEMIHOSTING', 'CONFIG_SYSTEM_ONLY'], 
if_false: files('stubs-all.c'))
  system_ss.add(when: ['CONFIG_SEMIHOSTING'], if_false: 
files('stubs-system.c'))
---

For mips more stubs are needed:

Undefined symbols for architecture arm64:
   "_qemu_semihosting_console_write", referenced from:
       _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
   "_uaccess_lock_user", referenced from:
       _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
       _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
       _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
       _uhi_fstat_cb in target_mips_tcg_sysemu_mips-semi.c.o
   "_uaccess_lock_user_string", referenced from:
       _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
       _mips_semihosting.cold.6 in target_mips_tcg_sysemu_mips-semi.c.o
       _mips_semihosting.cold.6 in target_mips_tcg_sysemu_mips-semi.c.o
   "_uaccess_strlen_user", referenced from:
       _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
   "_uaccess_unlock_user", referenced from:
       _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
       _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
       _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
       _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
       _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
       _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
       _uhi_fstat_cb in target_mips_tcg_sysemu_mips-semi.c.o
       ...

Re: [PATCH 3/3] semihosting: Restrict to TCG

[Philippe Mathieu-Daudé]

ping :)

On 12/6/24 15:12, Philippe Mathieu-Daudé wrote:
> Hi Paolo,
> 
> On 30/5/24 15:58, Philippe Mathieu-Daudé wrote:
>> On 30/5/24 09:31, Paolo Bonzini wrote:
>>> On Thu, May 30, 2024 at 9:22 AM Philippe Mathieu-Daudé
>>> <philmd@linaro.org> wrote:
>>>>
>>>> On 30/5/24 08:02, Paolo Bonzini wrote:
>>>>> On Wed, May 29, 2024 at 5:56 PM Philippe Mathieu-Daudé
>>>>> <philmd@linaro.org> wrote:
>>>>>> It is pointless to build semihosting when TCG is not available.
>>>>>
>>>>> Why? I would have naively assumed that a suitable semihosting API
>>>>> could be implemented by KVM. The justification (and thus the commit
>>>>> message) needs to be different for each architecture if it's a matter
>>>>> of instruction set or insufficient KVM userspace API.
>>>>
>>>> I wasn't sure where semihosting could be used so asked on IRC and
>>>> Alex told me TCG only. Maybe the current implementation is TCG
>>>> only, and I can reword. It certainly need some refactor to work
>>>> on KVM, because currently semihosting end calling the TCG probe_access
>>>> API, which I'm trying to restrict to TCG in order to ease linking
>>>> multiple libtcg for the single binary (see
>>>> https://lore.kernel.org/qemu-devel/20240529155918.6221-1-philmd@linaro.org/).
>>>
>>> Ok, that goes in the commit message though.
>>>
>>> "Semihosting currently uses the TCG probe_access API. It is pointless
>>> to have it in the binary when TCG isn't".
>>>
>>> and in the first two patches:
>>>
>>> "Semihosting currently uses the TCG probe_access API. To prepare for
>>> encoding the TCG dependency in Kconfig, do not enable it unless TCG is
>>> available".
>>>
>>> But then, "select FOO if TCG" mean that it can be compiled out; so
>>> perhaps "imply SEMIHOSTING if TCG" is better? Same for RISC-V's
>>> "select ARM_COMPATIBLE_SEMIHOSTING if TCG".
> 
> Building qemu-system-mips configured with --without-default-devices:
> 
> Undefined symbols for architecture arm64:
>    "_qemu_semihosting_console_write", referenced from:
>        _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>    "_semihost_sys_close", referenced from:
>        _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>    "_uaccess_strlen_user", referenced from:
>        _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>    ...
> 
> So this one has to use "select".
> 
> Similarly m68k:
> 
> Undefined symbols for architecture arm64:
>    "_semihost_sys_close", referenced from:
>        _do_m68k_semihosting in target_m68k_m68k-semi.c.o
>    ...
> 
> I can link m68k using semihosting stubs but I'm not sure it is right:
> 
> -- >8 --
> diff --git a/semihosting/stubs-target-all.c 
> b/semihosting/stubs-target-all.c
> new file mode 100644
> index 0000000000..1f33173f43
> --- /dev/null
> +++ b/semihosting/stubs-target-all.c
> @@ -0,0 +1,97 @@
> +/*
> + * Semihosting Stubs
> + *
> + * Copyright (c) 2024 Linaro Ltd
> + *
> + * Stubs for semihosting targets that don't actually do semihosting.
> + *
> + * SPDX-License-Identifier: GPL-2.0-or-later
> + */
> +
> +#include "qemu/osdep.h"
> +#include "exec/exec-all.h"
> +#include "semihosting/syscalls.h"
> +
> +void semihost_sys_open(CPUState *cs, gdb_syscall_complete_cb complete,
> +                       target_ulong fname, target_ulong fname_len,
> +                       int gdb_flags, int mode)
> +{
> +}
> +
> +void semihost_sys_close(CPUState *cs, gdb_syscall_complete_cb complete, 
> int fd)
> +{
> +}
> +
> +void semihost_sys_read_gf(CPUState *cs, gdb_syscall_complete_cb complete,
> +                          GuestFD *gf, target_ulong buf, target_ulong len)
> +{
> +}
> +
> +void semihost_sys_read(CPUState *cs, gdb_syscall_complete_cb complete,
> +                       int fd, target_ulong buf, target_ulong len)
> +{
> +}
> +
> +void semihost_sys_write_gf(CPUState *cs, gdb_syscall_complete_cb complete,
> +                           GuestFD *gf, target_ulong buf, target_ulong 
> len)
> +{
> +}
> +
> +void semihost_sys_write(CPUState *cs, gdb_syscall_complete_cb complete,
> +                        int fd, target_ulong buf, target_ulong len)
> +{
> +}
> +
> +void semihost_sys_lseek(CPUState *cs, gdb_syscall_complete_cb complete,
> +                        int fd, int64_t off, int gdb_whence)
> +{
> +}
> +
> +void semihost_sys_isatty(CPUState *cs, gdb_syscall_complete_cb 
> complete, int fd)
> +{
> +}
> +
> +void semihost_sys_flen(CPUState *cs, gdb_syscall_complete_cb fstat_cb,
> +                       gdb_syscall_complete_cb flen_cb, int fd,
> +                       target_ulong fstat_addr)
> +{
> +}
> +
> +void semihost_sys_fstat(CPUState *cs, gdb_syscall_complete_cb complete,
> +                        int fd, target_ulong addr)
> +{
> +}
> +
> +void semihost_sys_stat(CPUState *cs, gdb_syscall_complete_cb complete,
> +                       target_ulong fname, target_ulong fname_len,
> +                       target_ulong addr)
> +{
> +}
> +
> +void semihost_sys_remove(CPUState *cs, gdb_syscall_complete_cb complete,
> +                         target_ulong fname, target_ulong fname_len)
> +{
> +}
> +
> +void semihost_sys_rename(CPUState *cs, gdb_syscall_complete_cb complete,
> +                         target_ulong oname, target_ulong oname_len,
> +                         target_ulong nname, target_ulong nname_len)
> +{
> +}
> +
> +void semihost_sys_system(CPUState *cs, gdb_syscall_complete_cb complete,
> +                         target_ulong cmd, target_ulong cmd_len)
> +{
> +}
> +
> +void semihost_sys_gettimeofday(CPUState *cs, gdb_syscall_complete_cb 
> complete,
> +                               target_ulong tv_addr, target_ulong tz_addr)
> +{
> +}
> +
> +#ifndef CONFIG_USER_ONLY
> +void semihost_sys_poll_one(CPUState *cs, gdb_syscall_complete_cb complete,
> +                           int fd, GIOCondition cond, int timeout)
> +{
> +}
> +#endif
> diff --git a/semihosting/meson.build b/semihosting/meson.build
> index 34933e5a19..aa8b7a9913 100644
> --- a/semihosting/meson.build
> +++ b/semihosting/meson.build
> @@ -7,7 +7,7 @@ specific_ss.add(when: ['CONFIG_SEMIHOSTING', 
> 'CONFIG_SYSTEM_ONLY'], if_true: fil
>     'config.c',
>     'console.c',
>     'uaccess.c',
> -))
> +), if_false: files('stubs-target-all.c'))
> 
>   common_ss.add(when: ['CONFIG_SEMIHOSTING', 'CONFIG_SYSTEM_ONLY'], 
> if_false: files('stubs-all.c'))
>   system_ss.add(when: ['CONFIG_SEMIHOSTING'], if_false: 
> files('stubs-system.c'))
> ---
> 
> For mips more stubs are needed:
> 
> Undefined symbols for architecture arm64:
>    "_qemu_semihosting_console_write", referenced from:
>        _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>    "_uaccess_lock_user", referenced from:
>        _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>        _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>        _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>        _uhi_fstat_cb in target_mips_tcg_sysemu_mips-semi.c.o
>    "_uaccess_lock_user_string", referenced from:
>        _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>        _mips_semihosting.cold.6 in target_mips_tcg_sysemu_mips-semi.c.o
>        _mips_semihosting.cold.6 in target_mips_tcg_sysemu_mips-semi.c.o
>    "_uaccess_strlen_user", referenced from:
>        _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>    "_uaccess_unlock_user", referenced from:
>        _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>        _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>        _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>        _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>        _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>        _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>        _uhi_fstat_cb in target_mips_tcg_sysemu_mips-semi.c.o
>        ...
> 

Re: [PATCH 3/3] semihosting: Restrict to TCG

[Alex Bennée]

Philippe Mathieu-Daudé <philmd@linaro.org> writes:

> ping :)
>
> On 12/6/24 15:12, Philippe Mathieu-Daudé wrote:
>> Hi Paolo,
>> On 30/5/24 15:58, Philippe Mathieu-Daudé wrote:
>>> On 30/5/24 09:31, Paolo Bonzini wrote:
>>>> On Thu, May 30, 2024 at 9:22 AM Philippe Mathieu-Daudé
>>>> <philmd@linaro.org> wrote:
>>>>>
>>>>> On 30/5/24 08:02, Paolo Bonzini wrote:
>>>>>> On Wed, May 29, 2024 at 5:56 PM Philippe Mathieu-Daudé
>>>>>> <philmd@linaro.org> wrote:
>>>>>>> It is pointless to build semihosting when TCG is not available.
>>>>>>
>>>>>> Why? I would have naively assumed that a suitable semihosting API
>>>>>> could be implemented by KVM. The justification (and thus the commit
>>>>>> message) needs to be different for each architecture if it's a matter
>>>>>> of instruction set or insufficient KVM userspace API.
>>>>>
>>>>> I wasn't sure where semihosting could be used so asked on IRC and
>>>>> Alex told me TCG only. Maybe the current implementation is TCG
>>>>> only, and I can reword. It certainly need some refactor to work
>>>>> on KVM, because currently semihosting end calling the TCG probe_access
>>>>> API, which I'm trying to restrict to TCG in order to ease linking
>>>>> multiple libtcg for the single binary (see
>>>>> https://lore.kernel.org/qemu-devel/20240529155918.6221-1-philmd@linaro.org/).
>>>>
>>>> Ok, that goes in the commit message though.
>>>>
>>>> "Semihosting currently uses the TCG probe_access API. It is pointless
>>>> to have it in the binary when TCG isn't".
>>>>
>>>> and in the first two patches:
>>>>
>>>> "Semihosting currently uses the TCG probe_access API. To prepare for
>>>> encoding the TCG dependency in Kconfig, do not enable it unless TCG is
>>>> available".
>>>>
>>>> But then, "select FOO if TCG" mean that it can be compiled out; so
>>>> perhaps "imply SEMIHOSTING if TCG" is better? Same for RISC-V's
>>>> "select ARM_COMPATIBLE_SEMIHOSTING if TCG".
>> Building qemu-system-mips configured with --without-default-devices:
>> Undefined symbols for architecture arm64:
>>    "_qemu_semihosting_console_write", referenced from:
>>        _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>>    "_semihost_sys_close", referenced from:
>>        _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>>    "_uaccess_strlen_user", referenced from:
>>        _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>>    ...
>> So this one has to use "select".
>> Similarly m68k:
>> Undefined symbols for architecture arm64:
>>    "_semihost_sys_close", referenced from:
>>        _do_m68k_semihosting in target_m68k_m68k-semi.c.o
>>    ...
>> I can link m68k using semihosting stubs but I'm not sure it is
>> right:
>> -- >8 --
>> diff --git a/semihosting/stubs-target-all.c
>> b/semihosting/stubs-target-all.c
>> new file mode 100644
>> index 0000000000..1f33173f43
>> --- /dev/null
>> +++ b/semihosting/stubs-target-all.c
>> @@ -0,0 +1,97 @@
>> +/*
>> + * Semihosting Stubs
>> + *
>> + * Copyright (c) 2024 Linaro Ltd
>> + *
>> + * Stubs for semihosting targets that don't actually do semihosting.
>> + *
>> + * SPDX-License-Identifier: GPL-2.0-or-later
>> + */
>> +
>> +#include "qemu/osdep.h"
>> +#include "exec/exec-all.h"
>> +#include "semihosting/syscalls.h"
>> +
>> +void semihost_sys_open(CPUState *cs, gdb_syscall_complete_cb complete,
>> +                       target_ulong fname, target_ulong fname_len,
>> +                       int gdb_flags, int mode)
>> +{
>> +}
>> +
>> +void semihost_sys_close(CPUState *cs, gdb_syscall_complete_cb
>> complete, int fd)
>> +{
>> +}
>> +
>> +void semihost_sys_read_gf(CPUState *cs, gdb_syscall_complete_cb complete,
>> +                          GuestFD *gf, target_ulong buf, target_ulong len)
>> +{
>> +}
>> +
>> +void semihost_sys_read(CPUState *cs, gdb_syscall_complete_cb complete,
>> +                       int fd, target_ulong buf, target_ulong len)
>> +{
>> +}
>> +
>> +void semihost_sys_write_gf(CPUState *cs, gdb_syscall_complete_cb complete,
>> +                           GuestFD *gf, target_ulong buf,
>> target_ulong len)
>> +{
>> +}
>> +
>> +void semihost_sys_write(CPUState *cs, gdb_syscall_complete_cb complete,
>> +                        int fd, target_ulong buf, target_ulong len)
>> +{
>> +}
>> +
>> +void semihost_sys_lseek(CPUState *cs, gdb_syscall_complete_cb complete,
>> +                        int fd, int64_t off, int gdb_whence)
>> +{
>> +}
>> +
>> +void semihost_sys_isatty(CPUState *cs, gdb_syscall_complete_cb
>> complete, int fd)
>> +{
>> +}
>> +
>> +void semihost_sys_flen(CPUState *cs, gdb_syscall_complete_cb fstat_cb,
>> +                       gdb_syscall_complete_cb flen_cb, int fd,
>> +                       target_ulong fstat_addr)
>> +{
>> +}
>> +
>> +void semihost_sys_fstat(CPUState *cs, gdb_syscall_complete_cb complete,
>> +                        int fd, target_ulong addr)
>> +{
>> +}
>> +
>> +void semihost_sys_stat(CPUState *cs, gdb_syscall_complete_cb complete,
>> +                       target_ulong fname, target_ulong fname_len,
>> +                       target_ulong addr)
>> +{
>> +}
>> +
>> +void semihost_sys_remove(CPUState *cs, gdb_syscall_complete_cb complete,
>> +                         target_ulong fname, target_ulong fname_len)
>> +{
>> +}
>> +
>> +void semihost_sys_rename(CPUState *cs, gdb_syscall_complete_cb complete,
>> +                         target_ulong oname, target_ulong oname_len,
>> +                         target_ulong nname, target_ulong nname_len)
>> +{
>> +}
>> +
>> +void semihost_sys_system(CPUState *cs, gdb_syscall_complete_cb complete,
>> +                         target_ulong cmd, target_ulong cmd_len)
>> +{
>> +}
>> +
>> +void semihost_sys_gettimeofday(CPUState *cs,
>> gdb_syscall_complete_cb complete,
>> +                               target_ulong tv_addr, target_ulong tz_addr)
>> +{
>> +}
>> +
>> +#ifndef CONFIG_USER_ONLY
>> +void semihost_sys_poll_one(CPUState *cs, gdb_syscall_complete_cb complete,
>> +                           int fd, GIOCondition cond, int timeout)
>> +{
>> +}
>> +#endif
>> diff --git a/semihosting/meson.build b/semihosting/meson.build
>> index 34933e5a19..aa8b7a9913 100644
>> --- a/semihosting/meson.build
>> +++ b/semihosting/meson.build
>> @@ -7,7 +7,7 @@ specific_ss.add(when: ['CONFIG_SEMIHOSTING',
>> 'CONFIG_SYSTEM_ONLY'], if_true: fil
>>     'config.c',
>>     'console.c',
>>     'uaccess.c',
>> -))
>> +), if_false: files('stubs-target-all.c'))
>>   common_ss.add(when: ['CONFIG_SEMIHOSTING', 'CONFIG_SYSTEM_ONLY'],
>> if_false: files('stubs-all.c'))
>>   system_ss.add(when: ['CONFIG_SEMIHOSTING'], if_false:
>> files('stubs-system.c'))
>> ---
>> For mips more stubs are needed:
>> Undefined symbols for architecture arm64:
>>    "_qemu_semihosting_console_write", referenced from:
>>        _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>>    "_uaccess_lock_user", referenced from:
>>        _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>>        _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>>        _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>>        _uhi_fstat_cb in target_mips_tcg_sysemu_mips-semi.c.o
>>    "_uaccess_lock_user_string", referenced from:
>>        _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>>        _mips_semihosting.cold.6 in target_mips_tcg_sysemu_mips-semi.c.o
>>        _mips_semihosting.cold.6 in target_mips_tcg_sysemu_mips-semi.c.o
>>    "_uaccess_strlen_user", referenced from:
>>        _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>>    "_uaccess_unlock_user", referenced from:
>>        _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>>        _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>>        _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>>        _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>>        _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>>        _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>>        _uhi_fstat_cb in target_mips_tcg_sysemu_mips-semi.c.o
>>        ...
>> 

Oh sorry I was waiting for a re-spin. I should just apply the above to
3/3?

-- 
Alex Bennée
Virtualisation Tech Lead @ Linaro

Re: [PATCH 3/3] semihosting: Restrict to TCG

[Philippe Mathieu-Daudé]

On 18/6/24 15:56, Alex Bennée wrote:
> Philippe Mathieu-Daudé <philmd@linaro.org> writes:
> 
>> ping :)
>>
>> On 12/6/24 15:12, Philippe Mathieu-Daudé wrote:
>>> Hi Paolo,
>>> On 30/5/24 15:58, Philippe Mathieu-Daudé wrote:
>>>> On 30/5/24 09:31, Paolo Bonzini wrote:
>>>>> On Thu, May 30, 2024 at 9:22 AM Philippe Mathieu-Daudé
>>>>> <philmd@linaro.org> wrote:
>>>>>>
>>>>>> On 30/5/24 08:02, Paolo Bonzini wrote:
>>>>>>> On Wed, May 29, 2024 at 5:56 PM Philippe Mathieu-Daudé
>>>>>>> <philmd@linaro.org> wrote:
>>>>>>>> It is pointless to build semihosting when TCG is not available.
>>>>>>>
>>>>>>> Why? I would have naively assumed that a suitable semihosting API
>>>>>>> could be implemented by KVM. The justification (and thus the commit
>>>>>>> message) needs to be different for each architecture if it's a matter
>>>>>>> of instruction set or insufficient KVM userspace API.
>>>>>>
>>>>>> I wasn't sure where semihosting could be used so asked on IRC and
>>>>>> Alex told me TCG only. Maybe the current implementation is TCG
>>>>>> only, and I can reword. It certainly need some refactor to work
>>>>>> on KVM, because currently semihosting end calling the TCG probe_access
>>>>>> API, which I'm trying to restrict to TCG in order to ease linking
>>>>>> multiple libtcg for the single binary (see
>>>>>> https://lore.kernel.org/qemu-devel/20240529155918.6221-1-philmd@linaro.org/).
>>>>>
>>>>> Ok, that goes in the commit message though.
>>>>>
>>>>> "Semihosting currently uses the TCG probe_access API. It is pointless
>>>>> to have it in the binary when TCG isn't".
>>>>>
>>>>> and in the first two patches:
>>>>>
>>>>> "Semihosting currently uses the TCG probe_access API. To prepare for
>>>>> encoding the TCG dependency in Kconfig, do not enable it unless TCG is
>>>>> available".
>>>>>
>>>>> But then, "select FOO if TCG" mean that it can be compiled out; so
>>>>> perhaps "imply SEMIHOSTING if TCG" is better? Same for RISC-V's
>>>>> "select ARM_COMPATIBLE_SEMIHOSTING if TCG".
>>> Building qemu-system-mips configured with --without-default-devices:
>>> Undefined symbols for architecture arm64:
>>>     "_qemu_semihosting_console_write", referenced from:
>>>         _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>>>     "_semihost_sys_close", referenced from:
>>>         _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>>>     "_uaccess_strlen_user", referenced from:
>>>         _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>>>     ...
>>> So this one has to use "select".
>>> Similarly m68k:
>>> Undefined symbols for architecture arm64:
>>>     "_semihost_sys_close", referenced from:
>>>         _do_m68k_semihosting in target_m68k_m68k-semi.c.o
>>>     ...
>>> I can link m68k using semihosting stubs but I'm not sure it is
>>> right:
>>> -- >8 --
>>> diff --git a/semihosting/stubs-target-all.c
>>> b/semihosting/stubs-target-all.c
>>> new file mode 100644
>>> index 0000000000..1f33173f43
>>> --- /dev/null
>>> +++ b/semihosting/stubs-target-all.c
>>> @@ -0,0 +1,97 @@
>>> +/*
>>> + * Semihosting Stubs
>>> + *
>>> + * Copyright (c) 2024 Linaro Ltd
>>> + *
>>> + * Stubs for semihosting targets that don't actually do semihosting.
>>> + *
>>> + * SPDX-License-Identifier: GPL-2.0-or-later
>>> + */
>>> +
>>> +#include "qemu/osdep.h"
>>> +#include "exec/exec-all.h"
>>> +#include "semihosting/syscalls.h"
>>> +
>>> +void semihost_sys_open(CPUState *cs, gdb_syscall_complete_cb complete,
>>> +                       target_ulong fname, target_ulong fname_len,
>>> +                       int gdb_flags, int mode)
>>> +{
>>> +}
>>> +
>>> +void semihost_sys_close(CPUState *cs, gdb_syscall_complete_cb
>>> complete, int fd)
>>> +{
>>> +}
>>> +
>>> +void semihost_sys_read_gf(CPUState *cs, gdb_syscall_complete_cb complete,
>>> +                          GuestFD *gf, target_ulong buf, target_ulong len)
>>> +{
>>> +}
>>> +
>>> +void semihost_sys_read(CPUState *cs, gdb_syscall_complete_cb complete,
>>> +                       int fd, target_ulong buf, target_ulong len)
>>> +{
>>> +}
>>> +
>>> +void semihost_sys_write_gf(CPUState *cs, gdb_syscall_complete_cb complete,
>>> +                           GuestFD *gf, target_ulong buf,
>>> target_ulong len)
>>> +{
>>> +}
>>> +
>>> +void semihost_sys_write(CPUState *cs, gdb_syscall_complete_cb complete,
>>> +                        int fd, target_ulong buf, target_ulong len)
>>> +{
>>> +}
>>> +
>>> +void semihost_sys_lseek(CPUState *cs, gdb_syscall_complete_cb complete,
>>> +                        int fd, int64_t off, int gdb_whence)
>>> +{
>>> +}
>>> +
>>> +void semihost_sys_isatty(CPUState *cs, gdb_syscall_complete_cb
>>> complete, int fd)
>>> +{
>>> +}
>>> +
>>> +void semihost_sys_flen(CPUState *cs, gdb_syscall_complete_cb fstat_cb,
>>> +                       gdb_syscall_complete_cb flen_cb, int fd,
>>> +                       target_ulong fstat_addr)
>>> +{
>>> +}
>>> +
>>> +void semihost_sys_fstat(CPUState *cs, gdb_syscall_complete_cb complete,
>>> +                        int fd, target_ulong addr)
>>> +{
>>> +}
>>> +
>>> +void semihost_sys_stat(CPUState *cs, gdb_syscall_complete_cb complete,
>>> +                       target_ulong fname, target_ulong fname_len,
>>> +                       target_ulong addr)
>>> +{
>>> +}
>>> +
>>> +void semihost_sys_remove(CPUState *cs, gdb_syscall_complete_cb complete,
>>> +                         target_ulong fname, target_ulong fname_len)
>>> +{
>>> +}
>>> +
>>> +void semihost_sys_rename(CPUState *cs, gdb_syscall_complete_cb complete,
>>> +                         target_ulong oname, target_ulong oname_len,
>>> +                         target_ulong nname, target_ulong nname_len)
>>> +{
>>> +}
>>> +
>>> +void semihost_sys_system(CPUState *cs, gdb_syscall_complete_cb complete,
>>> +                         target_ulong cmd, target_ulong cmd_len)
>>> +{
>>> +}
>>> +
>>> +void semihost_sys_gettimeofday(CPUState *cs,
>>> gdb_syscall_complete_cb complete,
>>> +                               target_ulong tv_addr, target_ulong tz_addr)
>>> +{
>>> +}
>>> +
>>> +#ifndef CONFIG_USER_ONLY
>>> +void semihost_sys_poll_one(CPUState *cs, gdb_syscall_complete_cb complete,
>>> +                           int fd, GIOCondition cond, int timeout)
>>> +{
>>> +}
>>> +#endif
>>> diff --git a/semihosting/meson.build b/semihosting/meson.build
>>> index 34933e5a19..aa8b7a9913 100644
>>> --- a/semihosting/meson.build
>>> +++ b/semihosting/meson.build
>>> @@ -7,7 +7,7 @@ specific_ss.add(when: ['CONFIG_SEMIHOSTING',
>>> 'CONFIG_SYSTEM_ONLY'], if_true: fil
>>>      'config.c',
>>>      'console.c',
>>>      'uaccess.c',
>>> -))
>>> +), if_false: files('stubs-target-all.c'))
>>>    common_ss.add(when: ['CONFIG_SEMIHOSTING', 'CONFIG_SYSTEM_ONLY'],
>>> if_false: files('stubs-all.c'))
>>>    system_ss.add(when: ['CONFIG_SEMIHOSTING'], if_false:
>>> files('stubs-system.c'))
>>> ---
>>> For mips more stubs are needed:
>>> Undefined symbols for architecture arm64:
>>>     "_qemu_semihosting_console_write", referenced from:
>>>         _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>>>     "_uaccess_lock_user", referenced from:
>>>         _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>>>         _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>>>         _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>>>         _uhi_fstat_cb in target_mips_tcg_sysemu_mips-semi.c.o
>>>     "_uaccess_lock_user_string", referenced from:
>>>         _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>>>         _mips_semihosting.cold.6 in target_mips_tcg_sysemu_mips-semi.c.o
>>>         _mips_semihosting.cold.6 in target_mips_tcg_sysemu_mips-semi.c.o
>>>     "_uaccess_strlen_user", referenced from:
>>>         _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>>>     "_uaccess_unlock_user", referenced from:
>>>         _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>>>         _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>>>         _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>>>         _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>>>         _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>>>         _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>>>         _uhi_fstat_cb in target_mips_tcg_sysemu_mips-semi.c.o
>>>         ...
>>>
> 
> Oh sorry I was waiting for a re-spin. I should just apply the above to
> 3/3?

No, this is still unresolved :/ (this is a ping for Paolo :p)

Re: [PATCH 3/3] semihosting: Restrict to TCG

[Paolo Bonzini]

On Wed, Jun 12, 2024 at 3:13 PM Philippe Mathieu-Daudé
<philmd@linaro.org> wrote:
> Building qemu-system-mips configured with --without-default-devices:
>
> Undefined symbols for architecture arm64:
>    "_qemu_semihosting_console_write", referenced from:
>        _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>    "_semihost_sys_close", referenced from:
>        _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>    "_uaccess_strlen_user", referenced from:
>        _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>    ...
>
> So this one has to use "select".
>
> Similarly m68k:
>
> Undefined symbols for architecture arm64:
>    "_semihost_sys_close", referenced from:
>        _do_m68k_semihosting in target_m68k_m68k-semi.c.o
>    ...

Go ahead and use "select" for these. The file to be stubbed would have
to be target/m68k/m68k-semi.c (for do_m68k_semihosting) and
target/mips/tcg/sysemu/mips-semi.c (for mips_semihosting), not the
common code.

Paolo

Re: [PATCH 3/3] semihosting: Restrict to TCG

[Philippe Mathieu-Daudé]

On 19/6/24 09:49, Paolo Bonzini wrote:
> On Wed, Jun 12, 2024 at 3:13 PM Philippe Mathieu-Daudé
> <philmd@linaro.org> wrote:
>> Building qemu-system-mips configured with --without-default-devices:
>>
>> Undefined symbols for architecture arm64:
>>     "_qemu_semihosting_console_write", referenced from:
>>         _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>>     "_semihost_sys_close", referenced from:
>>         _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>>     "_uaccess_strlen_user", referenced from:
>>         _mips_semihosting in target_mips_tcg_sysemu_mips-semi.c.o
>>     ...
>>
>> So this one has to use "select".
>>
>> Similarly m68k:
>>
>> Undefined symbols for architecture arm64:
>>     "_semihost_sys_close", referenced from:
>>         _do_m68k_semihosting in target_m68k_m68k-semi.c.o
>>     ...
> 

> The file to be stubbed would have
> to be target/m68k/m68k-semi.c (for do_m68k_semihosting) and
> target/mips/tcg/sysemu/mips-semi.c (for mips_semihosting), not the
> common code.

Yes! Thank you, I'm was to blind to realize that...

Re: [PATCH 3/3] semihosting: Restrict to TCG

[Alex Bennée]

Paolo Bonzini <pbonzini@redhat.com> writes:

> On Wed, May 29, 2024 at 5:56 PM Philippe Mathieu-Daudé
> <philmd@linaro.org> wrote:
>> It is pointless to build semihosting when TCG is not available.
>
> Why? I would have naively assumed that a suitable semihosting API
> could be implemented by KVM. The justification (and thus the commit
> message) needs to be different for each architecture if it's a matter
> of instruction set or insufficient KVM userspace API.

For Arm at least the HLT instruction is an external debug feature and as
such not trappable by KVM.

>
> Paolo
>
>> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
>> ---
>>  semihosting/Kconfig | 1 +
>>  1 file changed, 1 insertion(+)
>>
>> diff --git a/semihosting/Kconfig b/semihosting/Kconfig
>> index eaf3a20ef5..fbe6ac87f9 100644
>> --- a/semihosting/Kconfig
>> +++ b/semihosting/Kconfig
>> @@ -1,6 +1,7 @@
>>
>>  config SEMIHOSTING
>>         bool
>> +       depends on TCG
>>
>>  config ARM_COMPATIBLE_SEMIHOSTING
>>         bool
>> --
>> 2.41.0
>>

-- 
Alex Bennée
Virtualisation Tech Lead @ Linaro

Re: [PATCH 0/3] semihosting: Restrict to TCG

[Richard Henderson]

On 5/29/24 08:55, Philippe Mathieu-Daudé wrote:
> Philippe Mathieu-Daudé (3):
>    target/mips: Restrict semihosting to TCG
>    target/riscv: Restrict semihosting to TCG
>    semihosting: Restrict to TCG

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

r~

Re: [PATCH 0/3] semihosting: Restrict to TCG

[Alex Bennée]

Philippe Mathieu-Daudé <philmd@linaro.org> writes:

> It is pointless to build semihosting when TCG is not available.
>
> Philippe Mathieu-Daudé (3):
>   target/mips: Restrict semihosting to TCG
>   target/riscv: Restrict semihosting to TCG
>   semihosting: Restrict to TCG

Queued to semihosting/next, thanks.

-- 
Alex Bennée
Virtualisation Tech Lead @ Linaro

Re: [PATCH 0/3] semihosting: Restrict to TCG

[Paolo Bonzini]

On Wed, May 29, 2024 at 9:11 PM Alex Bennée <alex.bennee@linaro.org> wrote:
>
> Philippe Mathieu-Daudé <philmd@linaro.org> writes:
>
> > It is pointless to build semihosting when TCG is not available.
> >
> > Philippe Mathieu-Daudé (3):
> >   target/mips: Restrict semihosting to TCG
> >   target/riscv: Restrict semihosting to TCG
> >   semihosting: Restrict to TCG
>
> Queued to semihosting/next, thanks.

Please don't, at least not in the current form. These are jokes, not
commit messages...

Paolo

Re: [PATCH 0/3] semihosting: Restrict to TCG

[Philippe Mathieu-Daudé]

On 30/5/24 08:03, Paolo Bonzini wrote:
> On Wed, May 29, 2024 at 9:11 PM Alex Bennée <alex.bennee@linaro.org> wrote:
>>
>> Philippe Mathieu-Daudé <philmd@linaro.org> writes:
>>
>>> It is pointless to build semihosting when TCG is not available.
>>>
>>> Philippe Mathieu-Daudé (3):
>>>    target/mips: Restrict semihosting to TCG
>>>    target/riscv: Restrict semihosting to TCG
>>>    semihosting: Restrict to TCG
>>
>> Queued to semihosting/next, thanks.
> 
> Please don't, at least not in the current form. These are jokes, not
> commit messages...

Sorry if it appears to you as a joke, I thought it would be something
trivial :(