From: Claudio Fontana <cfontana@suse.de>
To: Peter Maydell <peter.maydell@linaro.org>
Cc: "Eduardo Habkost" <ehabkost@redhat.com>,
"Alex Bennee" <alex.bennee@linaro.org>,
"Richard Henderson" <richard.henderson@linaro.org>,
"QEMU Developers" <qemu-devel@nongnu.org>,
"Marc-André Lureau" <marcandre.lureau@redhat.com>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Philippe Mathieu-Daudé" <philmd@redhat.com>
Subject: Re: dangers of current NEED_CPU_H, CONFIG_SOFTMMU, CONFIG_USER_ONLY
Date: Fri, 18 Dec 2020 01:14:50 +0100 [thread overview]
Message-ID: <c0f57e27-f0f3-8a99-ef06-ae17663b5878@suse.de> (raw)
In-Reply-To: <a58980ee-ae86-d3e0-8a5d-5e1fffee1b85@suse.de>
On 12/18/20 12:47 AM, Claudio Fontana wrote:
> On 12/17/20 11:49 PM, Peter Maydell wrote:
>> On Thu, 17 Dec 2020 at 22:45, Claudio Fontana <cfontana@suse.de> wrote:
>>>
>>> On 12/17/20 9:15 PM, Peter Maydell wrote:
>>>> On Thu, 17 Dec 2020 at 19:46, Claudio Fontana <cfontana@suse.de> wrote:
>>>> Yeah, don't try to ifdef out struct fields in common-compiled code...
>>>
>>> or should I? Using
>>>
>>> #ifdef NEED_CPU_H
>>> #ifdef CONFIG_SOFTMMU
>>>
>>> seems to do what I expect. Is it wrong?
>>
>> I think that gives you two versions of the struct:
>> - one seen by compiled-once files and by compiled-per-target softmmu files
>> - one seen by compiled-per-target user-only files
>>
>> Since the user-only target executables link both compiled-per-target
>> and compiled-once files I think they end up with different C files
>> thinking the same struct has a different layout/size which seems
>> like it's going to cause problems.
>>
>> thanks
>> -- PMM
>>
>
> It doesn't with
>
> #ifdef NEED_CPU_H
> #ifdef CONFIG_SOFTMMU
>
> just double checked the pointers from both files compiled per target and "common"; also all tests are ok.
>
> It immediately breaks if I replace those two defines with #ifndef CONFIG_USER_ONLY and recompile.
>
> I thought it was by design, but I guess this is just a "lucky" accident?
By lucky accident I mean that CONFIG_SOFTMMU is a check in the positive instead of the #if !defined(CONFIG_USER_ONLY), so it ends up working..
>
> Ciao,
>
> Claudio
>
prev parent reply other threads:[~2020-12-18 0:15 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-11 10:09 [PATCH v11 0/7] i386 cleanup PART 2 Claudio Fontana
2020-12-11 10:09 ` [PATCH v11 1/7] accel: extend AccelState and AccelClass to user-mode Claudio Fontana
2020-12-11 10:09 ` [PATCH v11 2/7] accel: replace struct CpusAccel with AccelOpsClass Claudio Fontana
2020-12-11 10:09 ` [PATCH v11 3/7] accel: introduce AccelCPUClass extending CPUClass Claudio Fontana
2020-12-11 10:09 ` [PATCH v11 4/7] i386: split cpu accelerators from cpu.c, using AccelCPUClass Claudio Fontana
2020-12-11 10:09 ` [PATCH v11 5/7] cpu: call AccelCPUClass::cpu_realizefn in cpu_exec_realizefn Claudio Fontana
2020-12-11 10:09 ` [PATCH v11 6/7] hw/core/cpu: call qemu_init_vcpu in cpu_common_realizefn Claudio Fontana
2020-12-11 10:09 ` [PATCH v11 7/7] cpu: introduce cpu_accel_instance_init Claudio Fontana
2020-12-17 19:46 ` dangers of current NEED_CPU_H, CONFIG_SOFTMMU, CONFIG_USER_ONLY (was: [PATCH v11 7/7] cpu: introduce cpu_accel_instance_init) Claudio Fontana
2020-12-17 20:15 ` Peter Maydell
2020-12-17 20:26 ` Peter Maydell
2020-12-17 21:13 ` Paolo Bonzini
2020-12-17 22:01 ` Eduardo Habkost
2020-12-17 20:32 ` Eduardo Habkost
2020-12-17 21:15 ` dangers of current NEED_CPU_H, CONFIG_SOFTMMU, CONFIG_USER_ONLY Claudio Fontana
2020-12-17 22:45 ` Claudio Fontana
2020-12-17 22:49 ` Peter Maydell
2020-12-17 23:47 ` Claudio Fontana
2020-12-18 0:14 ` Claudio Fontana [this message]
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