linux-kernel - [RFC PATCH v4 4/4] DO NOT MERGE: Test CPU isolation from managed interrupts

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Message-ID: <20241201124244.997754-5-costa.shul@redhat.com>
Date: Sun,  1 Dec 2024 14:42:44 +0200
From: Costa Shulyupin <costa.shul@...hat.com>
To: longman@...hat.com,
	ming.lei@...hat.com,
	pauld@...hat.com,
	juri.lelli@...hat.com,
	vschneid@...hat.com,
	Tejun Heo <tj@...nel.org>,
	Johannes Weiner <hannes@...xchg.org>,
	Michal Koutný <mkoutny@...e.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Costa Shulyupin <costa.shul@...hat.com>,
	linux-kernel@...r.kernel.org,
	cgroups@...r.kernel.org
Subject: [RFC PATCH v4 4/4] DO NOT MERGE: Test CPU isolation from managed interrupts

Test CPU isolation to ensure it is unaffected by managed interrupts.

Target: irq_restore_affinity_of_irq()

Managed interrupts can be created in various ways. One of them:

qemu-img create -f qcow2 test.qcow2 100M
virtme-ng -v --cpus 4 --rw --user root \
	--qemu-opts '\-drive id=d1,if=none,file=test.qcow2 \
	\-device nvme,id=i1,drive=d1,serial=1,bootindex=2'

Signed-off-by: Costa Shulyupin <costa.shul@...hat.com>

---

v4:
- Remove /sys/devices/system/cpu/cpu$isolate/online

v3:
- No changes

v2:
- use shell script only
---
 MAINTAINERS          |   2 +
 tests/managed_irq.sh | 135 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 137 insertions(+)
 create mode 100755 tests/managed_irq.sh

diff --git a/MAINTAINERS b/MAINTAINERS
index 1240e75ecf4b..4a753c2b34c1 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -26046,3 +26046,5 @@ S:	Buried alive in reporters
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
 F:	*
 F:	*/
+
+# disable warning
diff --git a/tests/managed_irq.sh b/tests/managed_irq.sh
new file mode 100755
index 000000000000..3763183fc987
--- /dev/null
+++ b/tests/managed_irq.sh
@@ -0,0 +1,135 @@
+#!/bin/zsh
+# SPDX-License-Identifier: GPL-2.0
+
+# shell script for testing dynamic isolation of managed interrupts.
+# Target: irq_restore_affinity_of_irq()
+
+# cpu# to isolate
+
+isolate=1
+
+managed_affined=$(
+	cd /sys/kernel/debug/irq/irqs/;
+	grep -l -e "affinity: $isolate$" /dev/null $(grep -l IRQD_AFFINITY_MANAGED *) |
+		head -n1
+)
+grep -l -e "affinity: $isolate$" /dev/null \
+	$(grep -l IRQD_AFFINITY_MANAGED /sys/kernel/debug/irq/irqs/*)
+test_irq=${managed_affined%% *}
+echo test_irq=$test_irq
+
+[ -z $test_irq ] && { echo No managed IRQs found;exit 1}
+
+cp -R /sys/kernel/debug/irq/irqs 0.irqs
+
+# Restart CPUs without changing the isolated cpuset.
+# Setup a baseline (the "control group")
+# to compare against the test of isolated mask.
+
+echo 0 > /sys/devices/system/cpu/cpu$isolate/online
+echo 0 > /sys/devices/system/cpu/cpu3/online
+echo 1 > /sys/devices/system/cpu/cpu$isolate/online
+echo 1 > /sys/devices/system/cpu/cpu3/online
+
+rm -rf baseline.irqs
+cp -R /sys/kernel/debug/irq/irqs baseline.irqs
+
+cd /sys/fs/cgroup/
+echo +cpuset > cgroup.subtree_control
+mkdir -p test
+echo isolated > test/cpuset.cpus.partition
+
+effective_affinity=/proc/irq/$test_irq/effective_affinity
+test_irq_debug=/sys/kernel/debug/irq/irqs/$test_irq
+
+errors=0
+
+check()
+{
+	local _status=$?
+	if [[ $_status == 0 ]]
+	then
+		echo PASS
+	else
+		let errors+=1
+		echo "FAIL #$errors:"
+		cat $test_irq_debug
+	fi
+	return $_status
+}
+
+check_activated()
+{
+	echo "Check normal irq affinity"
+	test 0 -ne $((0x$(cat $effective_affinity) & 1 << $isolate))
+	check
+	grep -q IRQD_ACTIVATED $test_irq_debug
+	check
+	grep -q IRQD_IRQ_STARTED $test_irq_debug
+	check
+	! grep -q IRQD_IRQ_DISABLED $test_irq_debug
+	check
+	! grep -q IRQD_IRQ_MASKED $test_irq_debug
+	check
+	! grep -q IRQD_MANAGED_SHUTDOWN $test_irq_debug
+	check
+}
+
+check_shutdown()
+{
+	echo "Check that irq affinity doesn't contain isolated cpu."
+	test 0 -eq $((0x$(cat $effective_affinity) & 1 << $isolate))
+	check
+	! grep -q IRQD_ACTIVATED $test_irq_debug
+	check
+	! grep -q IRQD_IRQ_STARTED $test_irq_debug
+	check
+	grep -q IRQD_IRQ_DISABLED $test_irq_debug
+	check
+	grep -q IRQD_IRQ_MASKED $test_irq_debug
+	check
+	grep -q IRQD_MANAGED_SHUTDOWN $test_irq_debug
+	check
+}
+
+echo "Isolating CPU #$isolate"
+echo $isolate > test/cpuset.cpus
+
+check_shutdown
+
+echo Reset cpuset
+echo "" > test/cpuset.cpus
+
+check_activated
+
+echo "Isolating CPU #$isolate again"
+echo $isolate > test/cpuset.cpus
+
+check_shutdown
+
+echo "Isolating CPU #3 and restore CPU #$isolate"
+echo 3 > test/cpuset.cpus
+
+check_activated
+
+echo Reset cpuset
+echo "" > test/cpuset.cpus
+
+rmdir test
+cd -
+
+rm -rf final.irqs
+cp -R /sys/kernel/debug/irq/irqs final.irqs
+
+sleep 1 # wait till IRQD_IRQ_INPROGRESS, IRQD_IRQ_MASKED
+
+if ! diff -r --ignore-matching-lines=Vector:: baseline.irqs final.irqs; then
+	echo diff failed;
+	let errors+=1
+fi
+
+#
+# return zero on success or number of errors
+#
+echo errors=$errors
+(return $errors)
-- 
2.47.0