Patch "selftests/mm: Update va_high_addr_switch.sh to check CPU for la57 flag" has been added to the 6.1-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    selftests/mm: Update va_high_addr_switch.sh to check CPU for la57 flag

to the 6.1-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     selftests-mm-update-va_high_addr_switch.sh-to-check-.patch
and it can be found in the queue-6.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 6f9e7161151e82abb47ea919ca4a247fb2baf144
Author: Audra Mitchell <audra@xxxxxxxxxx>
Date:   Fri Jan 19 15:58:01 2024 -0500

    selftests/mm: Update va_high_addr_switch.sh to check CPU for la57 flag
    
    [ Upstream commit 52e63d67b5bb423b33d7a262ac7f8bd375a90145 ]
    
    In order for the page table level 5 to be in use, the CPU must have the
    setting enabled in addition to the CONFIG option. Check for the flag to be
    set to avoid false test failures on systems that do not have this cpu flag
    set.
    
    The test does a series of mmap calls including three using the
    MAP_FIXED flag and specifying an address that is 1<<47 or 1<<48.  These
    addresses are only available if you are using level 5 page tables,
    which requires both the CPU to have the capabiltiy (la57 flag) and the
    kernel to be configured.  Currently the test only checks for the kernel
    configuration option, so this test can still report a false positive.
    Here are the three failing lines:
    
    $ ./va_high_addr_switch | grep FAILED
    mmap(ADDR_SWITCH_HINT, 2 * PAGE_SIZE, MAP_FIXED): 0xffffffffffffffff - FAILED
    mmap(HIGH_ADDR, MAP_FIXED): 0xffffffffffffffff - FAILED
    mmap(ADDR_SWITCH_HINT, 2 * PAGE_SIZE, MAP_FIXED): 0xffffffffffffffff - FAILED
    
    I thought (for about a second) refactoring the test so that these three
    mmap calls will only be run on systems with the level 5 page tables
    available, but the whole point of the test is to check the level 5
    feature...
    
    Link: https://lkml.kernel.org/r/20240119205801.62769-1-audra@xxxxxxxxxx
    Fixes: 4f2930c6718a ("selftests/vm: only run 128TBswitch with 5-level paging")
    Signed-off-by: Audra Mitchell <audra@xxxxxxxxxx>
    Cc: Rafael Aquini <raquini@xxxxxxxxxx>
    Cc: Shuah Khan <shuah@xxxxxxxxxx>
    Cc: Adam Sindelar <adam@xxxxxxxxxxxx>
    Cc: <stable@xxxxxxxxxxxxxxx>
    Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/tools/testing/selftests/vm/va_128TBswitch.sh b/tools/testing/selftests/vm/va_128TBswitch.sh
index 41580751dc51..231622b3a232 100755
--- a/tools/testing/selftests/vm/va_128TBswitch.sh
+++ b/tools/testing/selftests/vm/va_128TBswitch.sh
@@ -29,9 +29,15 @@ check_supported_x86_64()
 	# See man 1 gzip under '-f'.
 	local pg_table_levels=$(gzip -dcfq "${config}" | grep PGTABLE_LEVELS | cut -d'=' -f 2)
 
+	local cpu_supports_pl5=$(awk '/^flags/ {if (/la57/) {print 0;}
+		else {print 1}; exit}' /proc/cpuinfo 2>/dev/null)
+
 	if [[ "${pg_table_levels}" -lt 5 ]]; then
 		echo "$0: PGTABLE_LEVELS=${pg_table_levels}, must be >= 5 to run this test"
 		exit $ksft_skip
+	elif [[ "${cpu_supports_pl5}" -ne 0 ]]; then
+		echo "$0: CPU does not have the necessary la57 flag to support page table level 5"
+		exit $ksft_skip
 	fi
 }