Re: [PATCH] xen: Drop xenoprofile support

[Jan Beulich <jbeulich@xxxxxxxx>]

On 06.01.2026 09:43, Oleksii Kurochko wrote:
> 
> On 1/5/26 8:57 PM, Andrew Cooper wrote:
>> The most recent xenoprof change was 300ef0cb4fde ("x86: Add Xenoprofile
>> support for AMD Family16h") in 2013, despite there being 42 changes worth of
>> other cleanup/rearranging since then.
>>
>> Oprofile themselves dropped Xen support in commit 0c142c3a096d ("Remove
>> opcontrol and the GUI and processor models dependent on it") in 2014, as part
>> of releasing version 1.0 and switching over to using operf based on the Linux
>> perf_event subsystem.  Linux's version of this patch was merged in commit
>> 24880bef417f ("Merge tag 'oprofile-removal-5.12'") in 2021.
>>
>> Drop xenoprof and all supporting infrastructure, including the hypercall, the
>> XSM hook and flask vectors which lose their only caller, and even shrinks
>> struct domain by one pointer which wasn't properly excluded in
>> !CONFIG_XENOPROF builds.
>>
>> Retain the public xenoprof.h header as it is ABI, but note that the
>> functionality is removed.
>>
>> Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
>> ---
>> CC: Anthony PERARD <anthony.perard@xxxxxxxxxx>
>> CC: Michal Orzel <michal.orzel@xxxxxxx>
>> CC: Jan Beulich <jbeulich@xxxxxxxx>
>> CC: Julien Grall <julien@xxxxxxx>
>> CC: Roger Pau Monné <roger.pau@xxxxxxxxxx>
>> CC: Stefano Stabellini <sstabellini@xxxxxxxxxx>
>> CC: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>
>> CC: Daniel P. Smith <dpsmith@xxxxxxxxxxxxxxxxxxxx>
>>
>> Despite appearing to be architecture neutral, the internals of Xenoprof were
>> entirely x86-specific.  Another curiosity is that only the VMX MSR hooks
>> called passive_domain_do_{rd,wr}msr(), and I can't see how this was correct
>> for SVM.
>>
>> The real reason for finally getting around to this is the number of MISRA
>> violations reported by the eclair-x86_64-allcode job that I don't feel like
>> fixing.
>> ---
>>   CHANGELOG.md                            |   3 +
>>   docs/misc/xen-command-line.pandoc       |   6 -
>>   tools/flask/policy/modules/dom0.te      |   2 -
>>   xen/arch/x86/Makefile                   |   1 -
>>   xen/arch/x86/cpu/vpmu_amd.c             |   7 -
>>   xen/arch/x86/cpu/vpmu_intel.c           |   6 -
>>   xen/arch/x86/hvm/svm/entry.S            |   1 -
>>   xen/arch/x86/hvm/svm/svm.c              |   2 -
>>   xen/arch/x86/hvm/vmx/vmx.c              |   9 -
>>   xen/arch/x86/include/asm/xenoprof.h     |  95 ---
>>   xen/arch/x86/oprofile/Makefile          |   6 -
>>   xen/arch/x86/oprofile/backtrace.c       | 145 ----
>>   xen/arch/x86/oprofile/nmi_int.c         | 485 ------------
>>   xen/arch/x86/oprofile/op_counter.h      |  41 -
>>   xen/arch/x86/oprofile/op_model_athlon.c | 547 -------------
>>   xen/arch/x86/oprofile/op_model_p4.c     | 721 -----------------
>>   xen/arch/x86/oprofile/op_model_ppro.c   | 348 ---------
>>   xen/arch/x86/oprofile/op_x86_model.h    |  58 --
>>   xen/arch/x86/oprofile/xenoprof.c        | 106 ---
>>   xen/arch/x86/traps.c                    |   4 -
>>   xen/common/Kconfig                      |  11 -
>>   xen/common/Makefile                     |   1 -
>>   xen/common/compat/xenoprof.c            |  42 -
>>   xen/common/domain.c                     |   6 -
>>   xen/common/xenoprof.c                   | 977 ------------------------
>>   xen/include/Makefile                    |   1 -
>>   xen/include/hypercall-defs.c            |   6 -
>>   xen/include/public/xen.h                |   2 +-
>>   xen/include/public/xenoprof.h           |   2 +-
>>   xen/include/xen/sched.h                 |   3 -
>>   xen/include/xen/xenoprof.h              |  49 --
>>   xen/include/xsm/dummy.h                 |   7 -
>>   xen/include/xsm/xsm.h                   |   7 -
>>   xen/xsm/dummy.c                         |   2 -
>>   xen/xsm/flask/hooks.c                   |  35 -
>>   xen/xsm/flask/policy/access_vectors     |   4 -
>>   36 files changed, 5 insertions(+), 3743 deletions(-)
>>   delete mode 100644 xen/arch/x86/include/asm/xenoprof.h
>>   delete mode 100644 xen/arch/x86/oprofile/Makefile
>>   delete mode 100644 xen/arch/x86/oprofile/backtrace.c
>>   delete mode 100644 xen/arch/x86/oprofile/nmi_int.c
>>   delete mode 100644 xen/arch/x86/oprofile/op_counter.h
>>   delete mode 100644 xen/arch/x86/oprofile/op_model_athlon.c
>>   delete mode 100644 xen/arch/x86/oprofile/op_model_p4.c
>>   delete mode 100644 xen/arch/x86/oprofile/op_model_ppro.c
>>   delete mode 100644 xen/arch/x86/oprofile/op_x86_model.h
>>   delete mode 100644 xen/arch/x86/oprofile/xenoprof.c
>>   delete mode 100644 xen/common/compat/xenoprof.c
>>   delete mode 100644 xen/common/xenoprof.c
>>   delete mode 100644 xen/include/xen/xenoprof.h
>>
>> diff --git a/CHANGELOG.md b/CHANGELOG.md
>> index 3aaf5986231c..1663f6878ef2 100644
>> --- a/CHANGELOG.md
>> +++ b/CHANGELOG.md
>> @@ -15,6 +15,9 @@ The format is based on [Keep a 
>> Changelog](https://keepachangelog.com/en/1.0.0/)
>>      - The cpuid_mask_* command line options for legacy AMD CPUs.  These were
>>        deprecated in Xen 4.7 and noted not to work correctly with AMD CPUs 
>> from
>>        2011 onwards.
>> +   - Xenoprofile support.  Oprofile themselves removed support for Xen in 
>> 2014
>> +     prior to the version 1.0 release, and there has been no development 
>> since
>> +     before then in Xen.
> 
> LGTM:
> Acked-by: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx> # CHANGELOG.md
> 
> Nit: It is necessary to drop the extra space before "  Oprofile 
> themselves...".

Why would that be? See the other bullet point in context, which also uses a
two blanks after the inner full stop. This is deliberate.

Also - please trim your replies.

Jan