Hi Marc,
On 5/5/21 8:03 PM, Marc Zyngier wrote:
> Hi Eric,
>
> On Tue, 04 May 2021 15:47:36 +0100,
> Auger Eric <eric.auger@xxxxxxxxxx> wrote:
>>
>> Hi David, Marc,
>>
>> On 8/5/20 7:56 PM, Marc Zyngier wrote:
>>> From: David Brazdil <dbrazdil@xxxxxxxxxx>
>>>
>>> Add new folders arch/arm64/kvm/hyp/{vhe,nvhe} and Makefiles for building code
>>> that runs in EL2 under VHE/nVHE KVM, repsectivelly. Add an include folder for
>>> hyp-specific header files which will include code common to VHE/nVHE.
>>>
>>> Build nVHE code with -D__KVM_NVHE_HYPERVISOR__, VHE code with
>>> -D__KVM_VHE_HYPERVISOR__.
>>>
>>> Under nVHE compile each source file into a `.hyp.tmp.o` object first, then
>>> prefix all its symbols with "__kvm_nvhe_" using `objcopy` and produce
>>> a `.hyp.o`. Suffixes were chosen so that it would be possible for VHE and nVHE
>>> to share some source files, but compiled with different CFLAGS.
>>>
>>> The nVHE ELF symbol prefix is added to kallsyms.c as ignored. EL2-only symbols
>>> will never appear in EL1 stack traces.
>>>
>>> Due to symbol prefixing, add a section in image-vars.h for aliases of symbols
>>> that are defined in nVHE EL2 and accessed by kernel in EL1 or vice versa.
>>>
>>> Signed-off-by: David Brazdil <dbrazdil@xxxxxxxxxx>
>>> Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
>>> Link: https://lore.kernel.org/r/20200625131420.71444-4-dbrazdil@xxxxxxxxxx
>>> ---
>>> arch/arm64/kernel/image-vars.h | 14 +++++++++++++
>>> arch/arm64/kvm/hyp/Makefile | 10 +++++++---
>>> arch/arm64/kvm/hyp/nvhe/Makefile | 34 ++++++++++++++++++++++++++++++++
>>> arch/arm64/kvm/hyp/vhe/Makefile | 17 ++++++++++++++++
>>> scripts/kallsyms.c | 1 +
>>> 5 files changed, 73 insertions(+), 3 deletions(-)
>>> create mode 100644 arch/arm64/kvm/hyp/nvhe/Makefile
>>> create mode 100644 arch/arm64/kvm/hyp/vhe/Makefile
>
> [...]
>
>>> diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c
>>> index 6dc3078649fa..0096cd965332 100644
>>> --- a/scripts/kallsyms.c
>>> +++ b/scripts/kallsyms.c
>>> @@ -109,6 +109,7 @@ static bool is_ignored_symbol(const char *name, char type)
>>> ".LASANPC", /* s390 kasan local symbols */
>>> "__crc_", /* modversions */
>>> "__efistub_", /* arm64 EFI stub namespace */
>>> + "__kvm_nvhe_", /* arm64 non-VHE KVM namespace */
>> The addition of this line seems to have introduced errors on the
>> 'vmlinux symtab matches kallsyms' perf test (perf test -v 1) which fails
>> on aarch64 for all __kvm_nvhe_ prefixed symbols, like
>>
>> ERR : <addr> : __kvm_nvhe___invalid not on kallsyms
>> ERR : <addr> : __kvm_nvhe___do_hyp_init not on kallsyms
>> ERR : <addr> : __kvm_nvhe___kvm_handle_stub_hvc not on kallsyms
>> ERR : <addr> : __kvm_nvhe_reset not on kallsyms
>> ../..
>>
>> I understand we willingly hided those symbols from /proc/kallsyms. Do
>> you confirm the right fix is to upgrade the perf test suite accordingly?
>
> Hmmm. This test always fail here, no matter whether I have this line
> or not:
sorry Marc I missed your reply,
>
> <quote>
> maz@big-leg-emma:~$ sudo perf_5.10 test -v 1
> 1: vmlinux symtab matches kallsyms :
> --- start ---
> test child forked, pid 664
> /proc/{kallsyms,modules} inconsistency while looking for "[bpf]" module!
> /proc/{kallsyms,modules} inconsistency while looking for "[bpf]" module!
> /proc/{kallsyms,modules} inconsistency while looking for "[bpf]" module!
> /proc/{kallsyms,modules} inconsistency while looking for "[bpf]" module!
> /proc/{kallsyms,modules} inconsistency while looking for "[bpf]" module!
> /proc/{kallsyms,modules} inconsistency while looking for "[bpf]" module!
> /proc/{kallsyms,modules} inconsistency while looking for "[bpf]" module!
> /proc/{kallsyms,modules} inconsistency while looking for "[bpf]" module!
> /proc/{kallsyms,modules} inconsistency while looking for "[bpf]" module!
> /proc/{kallsyms,modules} inconsistency while looking for "[bpf]" module!
> Looking at the vmlinux_path (8 entries long)
> symsrc__init: cannot get elf header.
> symsrc__init: cannot get elf header.
> Couldn't find a vmlinux that matches the kernel running on this machine, skipping test
> test child finished with -2
> ---- end ----
> vmlinux symtab matches kallsyms: Skip
> </quote>
>
> Rookie question: How do you provide a kernel to the test framework?
On my end I compiled and installed a kernel and compiled perf from that
same kernel. Should work. I don't know how to point to a specific vmlinux
Thanks
Eric
>
> Thanks,
>
> M.
>
