On Wed, Aug 13, 2025 at 08:36:45PM -0500, arraybo...@gmail.com wrote:
> From: Aaron Rainbolt <arraybo...@gmail.com>
>
> Xen traditionally allows customizing guest behavior by passing arguments
> to the VM kernel via the kernel command line. This is no longer possible
> when using GRUB with Xen, as the kernel command line is decided by the
> GRUB configuration file within the guest, not data passed to the guest
> by Xen.
>
> To work around this limitation, enable GRUB to parse a command line
> passed to it by Xen, and expose data from the command line to the GRUB
> configuration as environment variables. These variables can be used in
> the GRUB configuration for any desired purpose, such as extending the
> kernel command line passed to the guest. The command line format is
> inspired by the Linux kernel's command line format.
>
> To reduce the risk of misuse, abuse, or accidents in production, the
> command line will only be parsed if it consists entirely of 7-bit ASCII
> characters, only alphabetical characters and underscores are permitted
> in variable names, and all variable names must start with the string
> "xen_grub_env_". This also allows room for expanding the command line
> arguments accepted by GRUB in the future, should other arguments end up
> becoming desirable in the future.
>
> Signed-off-by: Aaron Rainbolt <arraybo...@gmail.com>
Reviewed-by: Daniel Kiper <daniel.ki...@oracle.com>
... but two nits below...
> + else if (is_key_safe (ps.current_word, ps.current_word_len - 1) ==
> true)
> + {
> + param_dict_pos = param_dict_len++;
> + param_keys[param_dict_pos] = grub_malloc (ps.current_word_len);
> + if (param_keys == NULL)
> + goto cleanup_main;
> + param_vals[param_dict_pos] = grub_malloc (2);
grub_zalloc()
> + if (param_vals == NULL)
> + goto cleanup_main;
> +
> + grub_strncpy (param_keys[param_dict_pos], ps.current_word,
> + ps.current_word_len);
> + if (param_keys[param_dict_pos][ps.current_word_len - 1] != '\0' )
> + grub_fatal ("NUL terminator missing from key during Xen cmdline
> parsing");
> + grub_strcpy (param_vals[param_dict_pos], "1");
*param_vals[param_dict_pos] = '1';
I can fix these two issues for you before push...
If I do not hear any objections from Xen community in a week or
so I will push this patch into GRUB upstream git repo.
Anyway, thank you for doing this work!
Daniel
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