On Mon, Jun 27, 2022 at 06:13:32PM +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.
>
> Running `sudo make -C tools/testing/selftests TARGETS=vm run_tests`
> produces the desired output:
>
> ```
> ---------------------------
> running ./va_128TBswitch.sh
> ---------------------------
> ./va_128TBswitch.sh: PG_TABLE_LEVELS=4, must be >= 5 to run this test
> [SKIP]
> -------------------------------
> ```
>
> v2:
> - Function variables declared local
> - Fixed variable name typo in Makefile
> - Comment to explain gzip -dcfq
>
> Signed-off-by: Adam Sindelar <adam@xxxxxxxxxxxx>
> ---
> tools/testing/selftests/vm/Makefile | 1 +
> tools/testing/selftests/vm/run_vmtests.sh | 2 +-
> tools/testing/selftests/vm/va_128TBswitch.sh | 39 ++++++++++++++++++++
> 3 files changed, 41 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..7860d0969888 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
>
> 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..767a6465b5d2
> --- /dev/null
> +++ b/tools/testing/selftests/vm/va_128TBswitch.sh
> @@ -0,0 +1,39 @@
> +#!/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
> +
> +# Kselftest framework requirement - SKIP code is 4.
> +ksft_skip=4
> +
> +die()
> +{
> + echo "$1"
> + exit $exitcode
> +}
> +
> +check_test_requirements()
> +{
> + local config="/proc/config.gz"
> + [[ -f "${config}" ]] || config="/boot/config-$(uname -r)"
> + [[ -f "${config}" ]] || die "Cannot find kernel config in /proc or /boot"
> +
> + # gzip -dcfq automatically handles both compressed and plaintext input.
> + # See man 1 gzip under '-f'.
> + local pg_table_levels=$(gzip -dcfq "${config}" | grep PGTABLE_LEVELS | cut -d'=' -f 2)
> +
> + 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
>
Apologies for sending the v2 out twice - I had the VM crash in the
middle of sending the first email.
-Adam
