On 2024/10/19 3:34 AM, Bjorn Helgaas wrote:
On Tue, Sep 03, 2024 at 06:44:26PM -0700, Joseph Jang wrote:
Validate there are no duplicate hwirq from the irq debug
file system /sys/kernel/debug/irq/irqs/* per chip name.
One example log show 2 duplicated hwirq in the irq debug
file system.
$ sudo cat /sys/kernel/debug/irq/irqs/163
handler: handle_fasteoi_irq
device: 0019:00:00.0
<SNIP>
node: 1
affinity: 72-143
effectiv: 76
domain: irqchip@0x0000100022040000-3
hwirq: 0xc8000000
chip: ITS-MSI
flags: 0x20
$ sudo cat /sys/kernel/debug/irq/irqs/174
handler: handle_fasteoi_irq
device: 0039:00:00.0
<SNIP>
node: 3
affinity: 216-287
effectiv: 221
domain: irqchip@0x0000300022040000-3
hwirq: 0xc8000000
chip: ITS-MSI
flags: 0x20
The irq-check.sh can help to collect hwirq and chip name from
/sys/kernel/debug/irq/irqs/* and print error log when find duplicate
hwirq per chip name.
Kernel patch ("PCI/MSI: Fix MSI hwirq truncation") [1] fix above issue.
[1]: https://lore.kernel.org/all/20240115135649.708536-1-vidyas@xxxxxxxxxx/
I don't know enough about this issue to understand the details. It
seems like you look for duplicate hwirqs in chips with the same name,
e.g., "ITS-MSI" in this case? That name seems too generic to me
(might there be several instances of "ITS-MSI" in a system?)
As I know, each PCIe device typically has only one ITS-MSI controller.
Having multiple ITS-MSI instances for the same device would lead to
confusion and potential conflicts in interrupt routing.
Also, the name may come from chip->irq_print_chip(), so it apparently
relies on irqchip drivers to make the names unique if there are
multiple instances?
I would have expected looking for duplicates inside something more
specific, like "irqchip@0x0000300022040000-3". But again, I don't
know enough about the problem to speak confidently here.
In our case, If we look for duplicates by different irq domains like
"irqchip@0x0000100022040000-3" and "irqchip@0x0000300022040000-3" as
following example.
$ sudo cat /sys/kernel/debug/irq/irqs/163
handler: handle_fasteoi_irq
device: 0019:00:00.0
<SNIP>
node: 1
affinity: 72-143
effectiv: 76
domain: irqchip@0x0000100022040000-3
hwirq: 0xc8000000
chip: ITS-MSI
flags: 0x20
$ sudo cat /sys/kernel/debug/irq/irqs/174
handler: handle_fasteoi_irq
device: 0039:00:00.0
<SNIP>
node: 3
affinity: 216-287
effectiv: 221
domain: irqchip@0x0000300022040000-3
hwirq: 0xc8000000
chip: ITS-MSI
flags: 0x20
We could not detect the duplicated hwirq number (0xc8000000) in this case.
Cosmetic nits:
- Tweak subject to match history (use "git log --oneline
tools/testing/selftests/drivers/" to see it), e.g.,
selftests: irq: Add check for duplicate hwirq
- Rewrap commit log to fill 75 columns. No point in using shorter
lines.
- Indent the "$ sudu cat ..." block by a couple spaces since it's
effectively a quotation, not part of the main text body.
- Possibly include sample output of irq-check.sh (also indented as a
quote) when run on the system where you manually found the
duplicate via "sudo cat /sys/kernel/debug/irq/irqs/..."
- Reword "The irq-check.sh can help ..." to something like this:
Add an irq-check.sh test to report errors when there are
duplicate hwirqs per chip name.
- Since the kernel patch has already been merged, cite it like this
instead of using the https://lore URL:
db744ddd59be ("PCI/MSI: Prevent MSI hardware interrupt number truncation")
If you agree to use irq chip name ("ITS-MSI") to scan duplicate hwirq, I
could send version 2 patch to fix above suggestions.
Thank you,
Joseph.
Signed-off-by: Joseph Jang <jjang@xxxxxxxxxx>
Reviewed-by: Matthew R. Ochs <mochs@xxxxxxxxxx>
---
tools/testing/selftests/drivers/irq/Makefile | 5 +++
tools/testing/selftests/drivers/irq/config | 2 +
.../selftests/drivers/irq/irq-check.sh | 39 +++++++++++++++++++
3 files changed, 46 insertions(+)
create mode 100644 tools/testing/selftests/drivers/irq/Makefile
create mode 100644 tools/testing/selftests/drivers/irq/config
create mode 100755 tools/testing/selftests/drivers/irq/irq-check.sh
diff --git a/tools/testing/selftests/drivers/irq/Makefile b/tools/testing/selftests/drivers/irq/Makefile
new file mode 100644
index 000000000000..d6998017c861
--- /dev/null
+++ b/tools/testing/selftests/drivers/irq/Makefile
@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0
+
+TEST_PROGS := irq-check.sh
+
+include ../../lib.mk
diff --git a/tools/testing/selftests/drivers/irq/config b/tools/testing/selftests/drivers/irq/config
new file mode 100644
index 000000000000..a53d3b713728
--- /dev/null
+++ b/tools/testing/selftests/drivers/irq/config
@@ -0,0 +1,2 @@
+CONFIG_GENERIC_IRQ_DEBUGFS=y
+CONFIG_GENERIC_IRQ_INJECTION=y
diff --git a/tools/testing/selftests/drivers/irq/irq-check.sh b/tools/testing/selftests/drivers/irq/irq-check.sh
new file mode 100755
index 000000000000..e784777043a1
--- /dev/null
+++ b/tools/testing/selftests/drivers/irq/irq-check.sh
@@ -0,0 +1,39 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+
+# This script need root permission
+uid=$(id -u)
+if [ $uid -ne 0 ]; then
+ echo "SKIP: Must be run as root"
+ exit 4
+fi
+
+# Ensure debugfs is mounted
+mount -t debugfs nodev /sys/kernel/debug 2>/dev/null
+if [ ! -d "/sys/kernel/debug/irq/irqs" ]; then
+ echo "SKIP: irq debugfs not found"
+ exit 4
+fi
+
+# Traverse the irq debug file system directory to collect chip_name and hwirq
+hwirq_list=$(for irq_file in /sys/kernel/debug/irq/irqs/*; do
+ # Read chip name and hwirq from the irq_file
+ chip_name=$(cat "$irq_file" | grep -m 1 'chip:' | awk '{print $2}')
+ hwirq=$(cat "$irq_file" | grep -m 1 'hwirq:' | awk '{print $2}' )
+
+ if [ -z "$chip_name" ] || [ -z "$hwirq" ]; then
+ continue
+ fi
+
+ echo "$chip_name $hwirq"
+done)
+
+dup_hwirq_list=$(echo "$hwirq_list" | sort | uniq -cd)
+
+if [ -n "$dup_hwirq_list" ]; then
+ echo "ERROR: Found duplicate hwirq"
+ echo "$dup_hwirq_list"
+ exit 1
+fi
+
+exit 0
--
2.34.1
