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Message-ID: <20250108114536.627715-13-vdonnefort@google.com>
Subject: [PATCH v2 12/12] KVM: arm64: Add kselftest for tracefs hyp tracefs
From: Vincent Donnefort <vdonnefort@google.com>
To: rostedt@goodmis.org, mhiramat@kernel.org, mathieu.desnoyers@efficios.com,
linux-trace-kernel@vger.kernel.org, maz@kernel.org, oliver.upton@linux.dev,
joey.gouly@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com
Cc: kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org,
jstultz@google.com, qperret@google.com, will@kernel.org,
kernel-team@android.com, linux-kernel@vger.kernel.org,
Vincent Donnefort <vdonnefort@google.com>
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Add a test to validate the newly introduced tracefs interface for the
pKVM hypervisor. This test covers the usage of extended timestamp and
coherence of the tracing clock.
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_=
asm.h
index 784f6b3ae892..60c42661d179 100644
--- a/arch/arm64/include/asm/kvm_asm.h
+++ b/arch/arm64/include/asm/kvm_asm.h
@@ -86,6 +86,7 @@ enum __kvm_host_smccc_func {
__KVM_HOST_SMCCC_FUNC___pkvm_reset_tracing,
__KVM_HOST_SMCCC_FUNC___pkvm_swap_reader_tracing,
__KVM_HOST_SMCCC_FUNC___pkvm_enable_event,
+ __KVM_HOST_SMCCC_FUNC___pkvm_selftest_event,
};
=20
#define DECLARE_KVM_VHE_SYM(sym) extern char sym[]
diff --git a/arch/arm64/include/asm/kvm_hypevents.h b/arch/arm64/include/as=
m/kvm_hypevents.h
index 0b98a87a1250..25d8e23a3cc6 100644
--- a/arch/arm64/include/asm/kvm_hypevents.h
+++ b/arch/arm64/include/asm/kvm_hypevents.h
@@ -28,4 +28,14 @@ HYP_EVENT(hyp_exit,
),
HE_PRINTK(" ")
);
+
+#ifdef CONFIG_PKVM_SELFTESTS
+HYP_EVENT(selftest,
+ HE_PROTO(void),
+ HE_STRUCT(),
+ HE_ASSIGN(),
+ HE_PRINTK(" ")
+);
#endif
+
+#endif /* __ARM64_KVM_HYPEVENTS_H_ */
diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig
index ead632ad01b4..fff9d24d7771 100644
--- a/arch/arm64/kvm/Kconfig
+++ b/arch/arm64/kvm/Kconfig
@@ -46,6 +46,7 @@ menuconfig KVM
config NVHE_EL2_DEBUG
bool "Debug mode for non-VHE EL2 object"
depends on KVM
+ select PKVM_SELFTESTS
help
Say Y here to enable the debug mode for the non-VHE KVM EL2 object.
Failure reports will BUG() in the hypervisor. This is intended for
@@ -83,4 +84,13 @@ config PTDUMP_STAGE2_DEBUGFS
=20
If in doubt, say N.
=20
+config PKVM_SELFTESTS
+ bool "Protected KVM hypervisor selftests"
+ depends on KVM
+ default n
+ help
+ Say Y here to enable pKVM hypervisor testing infrastructure.
+
+ If unsure, say N.
+
endif # VIRTUALIZATION
diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/h=
yp-main.c
index 1920af496952..406b456d09c8 100644
--- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c
+++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
@@ -436,6 +436,19 @@ static void handle___pkvm_enable_event(struct kvm_cpu_=
context *host_ctxt)
cpu_reg(host_ctxt, 1) =3D __pkvm_enable_event(id, enable);
}
=20
+static void handle___pkvm_selftest_event(struct kvm_cpu_context *host_ctxt)
+{
+ int smc_ret =3D SMCCC_RET_NOT_SUPPORTED, ret =3D -EOPNOTSUPP;
+
+#ifdef CONFIG_PKVM_SELFTESTS
+ trace_selftest();
+ smc_ret =3D SMCCC_RET_SUCCESS;
+ ret =3D 0;
+#endif
+ cpu_reg(host_ctxt, 0) =3D smc_ret;
+ cpu_reg(host_ctxt, 1) =3D ret;
+}
+
typedef void (*hcall_t)(struct kvm_cpu_context *);
=20
#define HANDLE_FUNC(x) [__KVM_HOST_SMCCC_FUNC_##x] =3D (hcall_t)handle_##x
@@ -474,6 +487,7 @@ static const hcall_t host_hcall[] =3D {
HANDLE_FUNC(__pkvm_reset_tracing),
HANDLE_FUNC(__pkvm_swap_reader_tracing),
HANDLE_FUNC(__pkvm_enable_event),
+ HANDLE_FUNC(__pkvm_selftest_event),
};
=20
static void handle_host_hcall(struct kvm_cpu_context *host_ctxt)
diff --git a/arch/arm64/kvm/hyp_trace.c b/arch/arm64/kvm/hyp_trace.c
index fef082559a19..ac36f0b56fc2 100644
--- a/arch/arm64/kvm/hyp_trace.c
+++ b/arch/arm64/kvm/hyp_trace.c
@@ -895,6 +895,35 @@ static int hyp_trace_clock_show(struct seq_file *m, vo=
id *v)
}
DEFINE_SHOW_ATTRIBUTE(hyp_trace_clock);
=20
+#ifdef CONFIG_PKVM_SELFTESTS
+static int selftest_event_open(struct inode *inode, struct file *file)
+{
+ if (file->f_mode & FMODE_WRITE)
+ return kvm_call_hyp_nvhe(__pkvm_selftest_event);
+
+ return 0;
+}
+
+static ssize_t selftest_event_write(struct file *f, const char __user *buf,
+ size_t cnt, loff_t *pos)
+{
+ return cnt;
+}
+
+static const struct file_operations selftest_event_fops =3D {
+ .open =3D selftest_event_open,
+ .write =3D selftest_event_write,
+};
+
+static void hyp_trace_init_testing_tracefs(struct dentry *root)
+{
+ tracefs_create_file("selftest_event", TRACEFS_MODE_WRITE, root, NULL,
+ &selftest_event_fops);
+}
+#else
+static void hyp_trace_init_testing_tracefs(struct dentry *root) { }
+#endif
+
int hyp_trace_init_tracefs(void)
{
struct dentry *root, *per_cpu_root;
@@ -953,6 +982,7 @@ int hyp_trace_init_tracefs(void)
}
=20
hyp_trace_init_event_tracefs(root);
+ hyp_trace_init_testing_tracefs(root);
=20
return 0;
}
diff --git a/tools/testing/selftests/hyp-trace/Makefile b/tools/testing/sel=
ftests/hyp-trace/Makefile
new file mode 100644
index 000000000000..2a5b2e29667e
--- /dev/null
+++ b/tools/testing/selftests/hyp-trace/Makefile
@@ -0,0 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0
+all:
+
+TEST_PROGS :=3D hyp-trace-test
+
+include ../lib.mk
diff --git a/tools/testing/selftests/hyp-trace/config b/tools/testing/selft=
ests/hyp-trace/config
new file mode 100644
index 000000000000..39cee8ec30fa
--- /dev/null
+++ b/tools/testing/selftests/hyp-trace/config
@@ -0,0 +1,4 @@
+CONFIG_FTRACE=3Dy
+CONFIG_ARM64=3Dy
+CONFIG_KVM=3Dy
+CONFIG_PROTECTED_NVHE_TESTING=3Dy
diff --git a/tools/testing/selftests/hyp-trace/hyp-trace-test b/tools/testi=
ng/selftests/hyp-trace/hyp-trace-test
new file mode 100755
index 000000000000..868eb81bfb77
--- /dev/null
+++ b/tools/testing/selftests/hyp-trace/hyp-trace-test
@@ -0,0 +1,254 @@
+#!/bin/sh -e
+# SPDX-License-Identifier: GPL-2.0-only
+
+# hyp-trace-test - Tracefs for pKVM hypervisor test
+#
+# Copyright (C) 2024 - Google LLC
+# Author: Vincent Donnefort <vdonnefort@google.com>
+#
+
+log_and_die()
+{
+ echo "$1"
+
+ exit 1
+}
+
+host_clock()
+{
+ # BOOTTIME clock
+ awk '/now/ { printf "%.6f\n", $3 / 1000000000 }' /proc/timer_list
+}
+
+page_size()
+{
+ echo "$(awk '/KernelPageSize/ {print $2; exit}' /proc/self/smaps) * 10=
24" | bc
+}
+
+goto_hyp_trace()
+{
+ if [ -d "/sys/kernel/debug/tracing/hypervisor" ]; then
+ cd /sys/kernel/debug/tracing/hypervisor
+ return
+ fi
+
+ if [ -d "/sys/kernel/tracing/hypervisor" ]; then
+ cd /sys/kernel/tracing/hypervisor
+ return
+ fi
+
+ echo "ERROR: hyp tracing folder not found!"
+
+ exit 1
+}
+
+reset_hyp_trace()
+{
+ echo 0 > tracing_on
+ echo 0 > trace
+ for event in events/hypervisor/*; do
+ echo 0 > $event/enable
+ done
+}
+
+setup_hyp_trace()
+{
+ reset_hyp_trace
+
+ echo 16 > buffer_size_kb
+ echo 1 > events/hypervisor/selftest/enable
+ echo 1 > tracing_on
+}
+
+stop_hyp_trace()
+{
+ echo 0 > tracing_on
+}
+
+hyp_trace_loaded()
+{
+ grep -q "(loaded)" buffer_size_kb
+}
+
+write_events()
+{
+ local num=3D"$1"
+ local func=3D"$2"
+
+ for i in $(seq 1 $num); do
+ echo 1 > selftest_event
+ [ -z "$func" -o $i -eq $num ] || eval $func
+ done
+}
+
+consuming_read()
+{
+ local output=3D$1
+
+ cat trace_pipe > $output &
+
+ echo $!
+}
+
+run_test_consuming()
+{
+ local nr_events=3D$1
+ local func=3D$2
+ local tmp=3D"$(mktemp)"
+ local start_ts=3D0
+ local end_ts=3D0
+ local pid=3D0
+
+ echo "Output trace file: $tmp"
+
+ setup_hyp_trace
+ pid=3D$(consuming_read $tmp)
+
+ start_ts=3D$(host_clock)
+ write_events $nr_events $func
+ stop_hyp_trace
+ end_ts=3D$(host_clock)
+
+ kill $pid
+ validate_test $tmp $nr_events $start_ts $end_ts
+
+ rm $tmp
+}
+
+validate_test()
+{
+ local output=3D$1
+ local expected_events=3D$2
+ local start_ts=3D$3
+ local end_ts=3D$4
+ local prev_ts=3D$3
+ local ts=3D0
+ local num_events=3D0
+
+ IFS=3D$'\n'
+ for line in $(cat $output); do
+ echo "$line" | grep -q -E "^# " && continue
+ ts=3D$(echo "$line" | awk '{print $2}' | cut -d ':' -f1)
+ if [ $(echo "$ts<$prev_ts" | bc) -eq 1 ]; then
+ log_and_die "Error event @$ts < $prev_ts"
+ fi
+ prev_ts=3D$ts
+ num_events=3D$((num_events + 1))
+ done
+
+ if [ $(echo "$ts>$end_ts" | bc) -eq 1 ]; then
+ log_and_die "Error event @$ts > $end_ts"
+ fi
+
+ if [ $num_events -ne $expected_events ]; then
+ log_and_die "Expected $expected_events events, got $num_events"
+ fi
+}
+
+test_ts()
+{
+ echo "Test Timestamps..."
+
+ run_test_consuming 1000
+
+ echo "done."
+}
+
+test_extended_ts()
+{
+ echo "Test Extended Timestamps..."
+
+ run_test_consuming 1000 "sleep 0.1"
+
+ echo "done."
+}
+
+assert_loaded()
+{
+ hyp_trace_loaded || log_and_die "Expected loaded buffer"
+}
+
+assert_unloaded()
+{
+ ! hyp_trace_loaded || log_and_die "Expected unloaded buffer"
+}
+
+test_unloading()
+{
+ local tmp=3D"$(mktemp)"
+
+ echo "Test unloading..."
+
+ setup_hyp_trace
+ assert_loaded
+
+ echo 0 > tracing_on
+ assert_unloaded
+
+ pid=3D$(consuming_read $tmp)
+ sleep 1
+ assert_loaded
+ kill $pid
+ assert_unloaded
+
+ echo 1 > tracing_on
+ write_events 1
+ echo 0 > trace
+ assert_loaded
+ echo 0 > tracing_on
+ assert_unloaded
+
+ echo "done."
+}
+
+test_reset()
+{
+ local tmp=3D"$(mktemp)"
+
+ echo "Test Reset..."
+
+ setup_hyp_trace
+ write_events 5
+ echo 0 > trace
+ write_events 5
+
+ pid=3D$(consuming_read $tmp)
+ sleep 1
+ stop_hyp_trace
+ kill $pid
+
+ validate_test $tmp 5 0 $(host_clock)
+
+ rm $tmp
+
+ echo "done."
+}
+
+test_big_bpacking()
+{
+ local hyp_buffer_page_size=3D48
+ local page_size=3D$(page_size)
+ local min_buf_size=3D$(echo "$page_size * $page_size / ($hyp_buffer_pa=
ge_size * $(nproc))" | bc)
+
+ min_buf_size=3D$(echo "$min_buf_size * 2 / 1024" | bc)
+
+ echo "Test loading $min_buf_size kB buffer..."
+
+ reset_hyp_trace
+ echo $min_buf_size > buffer_size_kb
+ echo 1 > tracing_on
+
+ stop_hyp_trace
+
+ echo "done."
+}
+
+goto_hyp_trace
+
+test_reset
+test_unloading
+test_big_bpacking
+test_ts
+test_extended_ts
+
+exit 0
--=20
2.47.1.613.gc27f4b7a9f-goog