On Mon, Jun 27, 2022 at 07:38:37AM -0700, David Vernet wrote:
> On Mon, Jun 27, 2022 at 02:31:06PM +0200, Adam Sindelar wrote:
> > The test va_128TBswitch.c expects to be able to pass mmap an address hint
> > and length that cross the address 1<<47. This is not possible without
> > 5-level page tables, so the test fails.
> >
> > The test is already only run on 64-bit powerpc and x86 archs, but this
> > patch adds an additional check that skips the test if PG_TABLE_LEVELS < 5.
> > There is precedent for checking /proc/config.gz in selftests, e.g. in
> > selftests/firmware.
> >
> > Signed-off-by: Adam Sindelar <adam@xxxxxxxxxxxx>
>
> Hi Adam,
>
> Thanks for the patch. This is a great start -- left a few comments and
> questions.
>
> > ---
> > tools/testing/selftests/vm/Makefile | 1 +
> > tools/testing/selftests/vm/run_vmtests.sh | 2 +-
> > tools/testing/selftests/vm/va_128TBswitch.sh | 37 ++++++++++++++++++++
> > 3 files changed, 39 insertions(+), 1 deletion(-)
> > create mode 100755 tools/testing/selftests/vm/va_128TBswitch.sh
> >
> > diff --git a/tools/testing/selftests/vm/Makefile b/tools/testing/selftests/vm/Makefile
> > index c45e535ff4b8..74390f498859 100644
> > --- a/tools/testing/selftests/vm/Makefile
> > +++ b/tools/testing/selftests/vm/Makefile
> > @@ -91,6 +91,7 @@ endif
> > TEST_PROGS := run_vmtests.sh
> >
> > TEST_FILES := test_vmalloc.sh
> > +TEST_FILEs += va_128TBswitch.sh
>
> s/TEST_FILEs/TEST_FILES
>
> I recommend verifying that the installation worked as expected by running:
>
> $ make -C tools/testing/selftests TARGETS=vm install
>
> and ensuring that the shell script is output into
> tools/testing/selftests/kselftest_install/vm
>
Done - I think it runs and installs correctly. (All the files are where
I expect them to be, but I don't usually install selftests.)
Typo fixed in v2.
> > KSFT_KHDR_INSTALL := 1
> > include ../lib.mk
> > diff --git a/tools/testing/selftests/vm/run_vmtests.sh b/tools/testing/selftests/vm/run_vmtests.sh
> > index a2302b5faaf2..edda7350ccca 100755
> > --- a/tools/testing/selftests/vm/run_vmtests.sh
> > +++ b/tools/testing/selftests/vm/run_vmtests.sh
> > @@ -149,7 +149,7 @@ if [ $VADDR64 -ne 0 ]; then
> > run_test ./virtual_address_range
> >
> > # virtual address 128TB switch test
> > - run_test ./va_128TBswitch
> > + run_test ./va_128TBswitch.sh
> > fi # VADDR64
> >
> > # vmalloc stability smoke test
> > diff --git a/tools/testing/selftests/vm/va_128TBswitch.sh b/tools/testing/selftests/vm/va_128TBswitch.sh
> > new file mode 100755
> > index 000000000000..269cc674fe9e
> > --- /dev/null
> > +++ b/tools/testing/selftests/vm/va_128TBswitch.sh
> > @@ -0,0 +1,37 @@
> > +#!/bin/bash
> > +# SPDX-License-Identifier: GPL-2.0
> > +#
> > +# Copyright (C) 2022 Adam Sindelar (Meta) <adam@xxxxxxxxxxxx>
> > +#
> > +# This is a test for mmap behavior with 5-level paging. This script wraps the
> > +# real test to check that the kernel is configured to support at least 5
> > +# pagetable levels.
> > +
> > +# 1 means the test failed
> > +exitcode=1
>
> Should we change this to ksft_fail to match ksft_skip?
>
The convention seems to be to use exitcode in selftests/vm. (ksft_fail
is used in selftets/bpf.) I wanted to match the surrounding code.
> > +
> > +# Kselftest framework requirement - SKIP code is 4.
> > +ksft_skip=4
> > +
> > +die()
> > +{
> > + echo "$1"
> > + exit $exitcode
> > +}
> > +
> > +check_test_requirements()
> > +{
> > + config="/proc/config.gz"
>
> Can you make this variable local?
>
Done in v2, thanks.
> > + [[ -f "${config}" ]] || config="/boot/config-$(uname -r)"
> > + [[ -f "${config}" ]] || die "Cannot find kernel config in /proc or /boot"
> > +
> > + pg_table_levels=$(gzip -dcfq "${config}" | grep PGTABLE_LEVELS | cut -d'=' -f 2)
>
> Same here r.e. making it local.
>
> Also, does this work if we end up having to pull config from /boot where
> it's not gzipped? Perhaps we should create a variable called something like
> 'configs' which stores the output as either:
>
> $ local configs="$(zcat /proc/config.gz)"
>
> or
>
> $ local configs="$(cat /boot/config-$(uname -r))"
>
> Also, to the point above, just using zcat might be a bit simpler than
> invoking gzip -dcfq.
>
Variable made local in v2. I added a comment calling out '-f' from man 1
gzip - it's intended to be a passthrough for plaintext, while
decompressing gzip. (zcat does not work that way)
> > + if [[ "${pg_table_levels}" -lt 5 ]]; then
> > + echo "$0: PG_TABLE_LEVELS=${pg_table_levels}, must be >= 5 to run this test"
> > + exit $ksft_skip
> > + fi
> > +}
> > +
> > +check_test_requirements
> > +./va_128TBswitch
> > --
> > 2.35.1
> >
>
> Thanks,
> David
Thank you for reading!
-Adam
