[PATCH-for-9.0] hw/i386/pc: Deprecate 64-bit CPUs on ISA-only PC machine

[PATCH-for-9.0] hw/i386/pc: Deprecate 64-bit CPUs on ISA-only PC machine

[Philippe Mathieu-Daudé]

Per Daniel suggestion [*]:

 > isapc could arguably be restricted to just 32-bit CPU models,
 > because we should not need it to support any feature that didn't
 > exist prior to circa 1995. eg refuse to start with isapc, if 'lm'
 > is present in the CPU model for example.

[*] https://lore.kernel.org/qemu-devel/ZgQkS4RPmSt5Xa08@redhat.com/

Suggested-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
---
 docs/about/deprecated.rst | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst
index 7b548519b5..345c35507f 100644
--- a/docs/about/deprecated.rst
+++ b/docs/about/deprecated.rst
@@ -208,6 +208,13 @@ is no longer packaged in any distro making it harder to run the
 ``check-tcg`` tests. Unless we can improve the testing situation there
 is a chance the code will bitrot without anyone noticing.
 
+64-bit (x86_64) CPUs on the ``isapc`` machine (since 9.0)
+'''''''''''''''''''''''''''''''''''''''''''''''''''''''''
+
+The ``isapc`` machine aims to emulate old PC machine without PCI was
+generalized, so hardware available around 1995, before 64-bit intel
+CPUs were produced.
+
 System emulator machines
 ------------------------
 
-- 
2.41.0

Re: [PATCH-for-9.0] hw/i386/pc: Deprecate 64-bit CPUs on ISA-only PC machine

[Daniel P. Berrangé]

On Wed, Mar 27, 2024 at 04:35:17PM +0100, Philippe Mathieu-Daudé wrote:
> Per Daniel suggestion [*]:
> 
>  > isapc could arguably be restricted to just 32-bit CPU models,
>  > because we should not need it to support any feature that didn't
>  > exist prior to circa 1995. eg refuse to start with isapc, if 'lm'
>  > is present in the CPU model for example.
> 
> [*] https://lore.kernel.org/qemu-devel/ZgQkS4RPmSt5Xa08@redhat.com/
> 
> Suggested-by: Daniel P. Berrangé <berrange@redhat.com>
> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> ---
>  docs/about/deprecated.rst | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst
> index 7b548519b5..345c35507f 100644
> --- a/docs/about/deprecated.rst
> +++ b/docs/about/deprecated.rst
> @@ -208,6 +208,13 @@ is no longer packaged in any distro making it harder to run the
>  ``check-tcg`` tests. Unless we can improve the testing situation there
>  is a chance the code will bitrot without anyone noticing.
>  
> +64-bit (x86_64) CPUs on the ``isapc`` machine (since 9.0)
> +'''''''''''''''''''''''''''''''''''''''''''''''''''''''''
> +
> +The ``isapc`` machine aims to emulate old PC machine without PCI was
> +generalized, so hardware available around 1995, before 64-bit intel
> +CPUs were produced.
> +
>  System emulator machines
>  ------------------------

I would expect there to be a 'warn_report()' added to the isapc
init code somewhere to go along with this, that will later be
turned into an 'error_report' once the deprecation period is
over.

With regards,
Daniel
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