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| author | Peter Maydell <peter.maydell@linaro.org> | 2025-02-07 16:09:20 +0000 |
|---|---|---|
| committer | Peter Maydell <peter.maydell@linaro.org> | 2025-02-07 16:09:20 +0000 |
| commit | 751002e74a8e3fc2dd388d57a93e11d3624af6f6 (patch) | |
| tree | 20f686582a937b83314918ccd7988698dcf1cf13 | |
| parent | 76723b8ed7b8274a4e30cdf0a9f3e7c47ebe251a (diff) | |
| download | focaccia-qemu-751002e74a8e3fc2dd388d57a93e11d3624af6f6.tar.gz focaccia-qemu-751002e74a8e3fc2dd388d57a93e11d3624af6f6.zip | |
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the akita/terrier board types: https://mail.gnu.org/archive/html/qemu-devel/2007-07/msg00344.html Even then, it was an out-of-date mechanism from the kernel's point of view -- the kernel has had a comment since 2001 marking it as deprecated.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 <peter.maydell@linaro.org> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Message-id: 20250127123113.2947620-1-peter.maydell@linaro.org
| -rw-r--r-- | docs/about/deprecated.rst | 13 | ||||
| -rw-r--r-- | system/vl.c | 1 |
2 files changed, 14 insertions, 0 deletions
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: |