From: Peter Maydell Date: Fri, 7 Feb 2025 16:09:20 +0000 (+0000) Subject: qemu-options: Deprecate -old-param command line option X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=751002e74a8e3fc2dd388d57a93e11d3624af6f6;p=qemu.git qemu-options: Deprecate -old-param command line option The '-old-param' command line option is specific to Arm targets; it is very briefly documented as "old param mode". What this option actually does is change the behaviour when directly booting a guest kernel, so that command line arguments are passed to the kernel using the extremely old "param_struct" ABI, rather than the newer ATAGS or even newer DTB mechanisms. This support was added back in 2007 to support an old vendor kernel on the akita/terrier board types: https://mail.gnu.org/archive/html/qemu-devel/2007-07/msg00344.html Even then, it was an out-of-date mechanism from the kernel's point of view -- the kernel has had a comment since 2001 marking it as deprecated. As of mid-2024, the kernel only retained param_struct support for the RiscPC and Footbridge platforms: https://lore.kernel.org/linux-arm-kernel/2831c5a6-cfbf-4fe0-b51c-0396e5b0aeb7@app.fastmail.com/ None of the board types QEMU supports need param_struct support; mark this option as deprecated. Signed-off-by: Peter Maydell Reviewed-by: Daniel P. Berrangé Message-id: 20250127123113.2947620-1-peter.maydell@linaro.org --- diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst index 29de49351d..a4c7d64223 100644 --- a/docs/about/deprecated.rst +++ b/docs/about/deprecated.rst @@ -68,6 +68,19 @@ configurations (e.g. -smp drawers=1,books=1,clusters=1 for x86 PC machine) is marked deprecated since 9.0, users have to ensure that all the topology members described with -smp are supported by the target machine. +``-old-param`` option for booting Arm kernels via param_struct (since 10.0) +''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' + +The ``-old-param`` command line option is specific to Arm targets: +it is used when directly booting a guest kernel to pass it the +command line and other information via the old ``param_struct`` ABI, +rather than the newer ATAGS or DTB mechanisms. This option was only +ever needed to support ancient kernels on some old board types +like the ``akita`` or ``terrier``; it has been deprecated in the +kernel since 2001. None of the board types QEMU supports need +``param_struct`` support, so this option has been deprecated and will +be removed in a future QEMU version. + User-mode emulator command line arguments ----------------------------------------- diff --git a/system/vl.c b/system/vl.c index db8e604eba..aa91047c48 100644 --- a/system/vl.c +++ b/system/vl.c @@ -3469,6 +3469,7 @@ void qemu_init(int argc, char **argv) nb_prom_envs++; break; case QEMU_OPTION_old_param: + warn_report("-old-param is deprecated"); old_param = 1; break; case QEMU_OPTION_rtc: