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:
<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?
Thanks,
M.
--
Without deviation from the norm, progress is not possible.
