On Wed, Apr 24, 2019 at 09:34:46AM +0200, Sebastian Andrzej Siewior wrote:
In one of my rcutorture tests the TSC clocksource got marked unstable due to a large difference in the TSC value. I'm not sure if the guest run for a long time with disabled interrupts or if the host was very busy and didn't schedule the guest for some time. I took a look on the qemu/KVM options and decided to update the options:
Use kvm{32|64} as CPU. We could probably use `host' (like ARM does) for maximum available features but since we don't run any userland I'm not sure if it makes any difference.
Drop the "noapic" option, enable TSC deadline timer. There is no history why the APIC was disabled, I see no reason for it. The deadline timer is probably "nicer".
Additional config options. It ensures that the kernel knowns that it runs as a kvm guest and can use virt devices like the kvm-clock as clocksource. The kvm-clock was the main motivation here.
I didn't add a random HW device. It would make the random device ready earlier (not it doesn't complete the initialisation at all) but I doubt that there is any need for this.
Signed-off-by: Sebastian Andrzej Siewior bigeasy@linutronix.de
Thank you, Sebastian! Queued for review and testing.
Thanx, Paul
tools/testing/selftests/rcutorture/bin/functions.sh | 13 ++++++++++++- .../selftests/rcutorture/configs/rcu/CFcommon | 4 ++++ 2 files changed, 16 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/rcutorture/bin/functions.sh b/tools/testing/selftests/rcutorture/bin/functions.sh index 6bcb8b5b2ff22..be3c5c73d7e79 100644 --- a/tools/testing/selftests/rcutorture/bin/functions.sh +++ b/tools/testing/selftests/rcutorture/bin/functions.sh @@ -172,7 +172,7 @@ identify_qemu_append () { local console=ttyS0 case "$1" in qemu-system-x86_64|qemu-system-i386)
echo noapic selinux=0 initcall_debug debug
echo selinux=0 initcall_debug debug@@ -191,8 +191,19 @@ identify_qemu_append () { # Output arguments for qemu arguments based on the TORTURE_QEMU_MAC # and TORTURE_QEMU_INTERACTIVE environment variables. identify_qemu_args () {
- local KVM_CPU=""
- case "$1" in
- qemu-system-x86_64)
KVM_CPU=kvm64;;- qemu-system-i386)
KVM_CPU=kvm32;;- esac case "$1" in qemu-system-x86_64|qemu-system-i386)
echo -machine q35,accel=kvmecho -cpu ${KVM_CPU},x2apic=on,tsc-deadline=on,hypervisor=on,tsc_adjust=ondiff --git a/tools/testing/selftests/rcutorture/configs/rcu/CFcommon b/tools/testing/selftests/rcutorture/configs/rcu/CFcommon index d2d2a86139db1..322d5d40443cd 100644 --- a/tools/testing/selftests/rcutorture/configs/rcu/CFcommon +++ b/tools/testing/selftests/rcutorture/configs/rcu/CFcommon @@ -1,2 +1,6 @@ CONFIG_RCU_TORTURE_TEST=y CONFIG_PRINTK_TIME=y +CONFIG_HYPERVISOR_GUEST=y +CONFIG_PARAVIRT=y +CONFIG_PARAVIRT_SPINLOCKS=y
+CONFIG_KVM_GUEST=y
2.20.1