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> -----Original Message-----
> From: Jan Beulich <[email protected]>
> Sent: Tuesday, November 25, 2025 2:39 PM
> To: Penny, Zheng <[email protected]>; Andrew Cooper
> <[email protected]>
> Cc: Huang, Ray <[email protected]>; [email protected]; Roger
> Pau Monné <[email protected]>; Anthony PERARD
> <[email protected]>; Juergen Gross <[email protected]>; xen-
> [email protected]
> Subject: Re: [PATCH v4 02/24] xen: consolidate cpuid library
>
> On 21.11.2025 11:57, Penny Zheng wrote:
> > There are some cpuid library functions only referenced in
> > XEN_DOMCTL_get{,set}_cpu_policy-case, and shall be wrapped with
> > CONFIG_MGMT_HYPERCALLS later, otherwise they will become unreachable
> > when MGMT_HYPERCALLS=n, and hence violate Misra 2.1
> > - x86_cpu_policy_clear_out_of_range_leaves
> > - zero_leaves
> > - x86_cpuid_copy_to_buffer
> > - copy_leaf_to_buffer
> > - x86_cpuid_copy_from_buffer
> > We seperate these functions by moving other functions to a new file
> > named cpuid-generic.c, and modify related Makefile-s to retain same
> > behavior.
> >
> > Signed-off-by: Penny Zheng <[email protected]>
> > ---
> > v3 -> v4:
> > - new commit
> > ---
> > tools/fuzz/cpu-policy/Makefile | 2 +-
> > tools/fuzz/x86_instruction_emulator/Makefile | 10 +-
> > tools/libs/guest/Makefile.common | 2 +-
> > tools/tests/cpu-policy/Makefile | 2 +-
> > tools/tests/x86_emulator/Makefile | 2 +-
> > xen/lib/x86/Makefile | 1 +
> > xen/lib/x86/cpuid-generic.c | 273 +++++++++++++++++++
> > xen/lib/x86/cpuid.c | 260 ------------------
> > 8 files changed, 283 insertions(+), 269 deletions(-) create mode
> > 100644 xen/lib/x86/cpuid-generic.c
>
> Andrew - what's your take on such a split? Personally I'm not overly happy to
> see
> related functions be scattered across two files. The separation also feels
> pretty
> random, posing the risk that later some of the code may need to move back.
>
Right now, I could not think a better way to guard
x86_cpuid_copy_from{,to}_buffer with MGMT_HYPERCALLS without split, any better
suggestion? Or maybe I could add up some explanations on the file
cpuid_generic.c head note to explain the diffs between itself and cpuid.c,
something like:
```
The difference between cpuid.c and cpuid_generic.c is that the former contains
library functions that has only been referenced in management hypercalls, such
as sysctl, domctl, etc. See comment for MGMT_HYPERCALLS.
```
> Penny, I also don't think "consolidate" is what is happening here.
> Perhaps "split" would be getting closer?
>
> Jan
