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From: Zenghui Yu <yuzenghui@huawei.com>
To: Marc Zyngier <maz@kernel.org>, <drjones@redhat.com>,
	James Morse <james.morse@arm.com>,
	<julien.thierry.kdev@gmail.com>, <suzuki.poulose@arm.com>
Cc: linux-arm-kernel@lists.infradead.org,
	kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org
Subject: kvm-unit-tests: psci_cpu_on_test FAILed
Date: Fri, 2 Aug 2019 18:56:51 +0800	[thread overview]
Message-ID: <3ddf8766-6f02-b655-1b80-d8a7fd016509@huawei.com> (raw)

Hi folks,

Running kvm-unit-tests with Linux 5.3.0-rc2 on Kunpeng 920, we will get
the following fail info:

	[...]
	FAIL psci (4 tests, 1 unexpected failures)
	[...]
and
	[...]
	INFO: unexpected cpu_on return value: caller=CPU9, ret=-2
	FAIL: cpu-on
	SUMMARY: 4 tests, 1 unexpected failures


I think this is an issue had been fixed once by commit 6c7a5dce22b3
("KVM: arm/arm64: fix races in kvm_psci_vcpu_on"), which makes use of
kvm->lock mutex to fix the race between two PSCI_CPU_ON calls - one
does reset on the MPIDR register whilst another reads it.

But commit 358b28f09f0 ("arm/arm64: KVM: Allow a VCPU to fully reset
itself") later moves the reset work into check_vcpu_requests(), by
making a KVM_REQ_VCPU_RESET request in PSCI code. Thus the reset work
has not been protected by kvm->lock mutex anymore, and the race shows up
again...

Do we need a fix for this issue? At least achieve a mutex execution
between the reset of MPIDR and kvm_mpidr_to_vcpu()?


Thanks,
zenghui

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             reply	other threads:[~2019-08-02 11:00 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-02 10:56 Zenghui Yu [this message]
2019-08-02 11:32 ` kvm-unit-tests: psci_cpu_on_test FAILed Andrew Jones
2019-08-02 15:56 ` Marc Zyngier
2019-08-03  9:27   ` Zenghui Yu
2019-08-03 10:10     ` Marc Zyngier
2019-08-05  2:38       ` Zenghui Yu

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