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| author | Andrew Jones <drjones@redhat.com> | 2017-04-18 17:59:58 +0200 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2017-08-26 02:14:36 +0100 |
| commit | 7c2173a8169111df531cd75cb967ea3a01ded682 (patch) | |
| tree | f18500193c401368343f1d4765e2fe1464d399db /arch | |
| parent | 2c30708e811c261a491db247771f2829697aaffa (diff) | |
| download | linux-stable-7c2173a8169111df531cd75cb967ea3a01ded682.tar.gz linux-stable-7c2173a8169111df531cd75cb967ea3a01ded682.tar.bz2 linux-stable-7c2173a8169111df531cd75cb967ea3a01ded682.zip | |
KVM: arm/arm64: fix races in kvm_psci_vcpu_on
commit 6c7a5dce22b3f3cc44be098e2837fa6797edb8b8 upstream.
Fix potential races in kvm_psci_vcpu_on() by taking the kvm->lock
mutex. In general, it's a bad idea to allow more than one PSCI_CPU_ON
to process the same target VCPU at the same time. One such problem
that may arise is that one PSCI_CPU_ON could be resetting the target
vcpu, which fills the entire sys_regs array with a temporary value
including the MPIDR register, while another looks up the VCPU based
on the MPIDR value, resulting in no target VCPU found. Resolves both
races found with the kvm-unit-tests/arm/psci unit test.
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Christoffer Dall <cdall@linaro.org>
Reported-by: Levente Kurusa <lkurusa@redhat.com>
Suggested-by: Christoffer Dall <cdall@linaro.org>
Signed-off-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Christoffer Dall <cdall@linaro.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm/kvm/psci.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/arch/arm/kvm/psci.c b/arch/arm/kvm/psci.c index 09cf37737ee2..5030facb4aaf 100644 --- a/arch/arm/kvm/psci.c +++ b/arch/arm/kvm/psci.c @@ -191,9 +191,10 @@ int kvm_psci_version(struct kvm_vcpu *vcpu) static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu) { - int ret = 1; + struct kvm *kvm = vcpu->kvm; unsigned long psci_fn = *vcpu_reg(vcpu, 0) & ~((u32) 0); unsigned long val; + int ret = 1; switch (psci_fn) { case PSCI_0_2_FN_PSCI_VERSION: @@ -213,7 +214,9 @@ static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu) break; case PSCI_0_2_FN_CPU_ON: case PSCI_0_2_FN64_CPU_ON: + mutex_lock(&kvm->lock); val = kvm_psci_vcpu_on(vcpu); + mutex_unlock(&kvm->lock); break; case PSCI_0_2_FN_AFFINITY_INFO: case PSCI_0_2_FN64_AFFINITY_INFO: @@ -269,6 +272,7 @@ static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu) static int kvm_psci_0_1_call(struct kvm_vcpu *vcpu) { + struct kvm *kvm = vcpu->kvm; unsigned long psci_fn = *vcpu_reg(vcpu, 0) & ~((u32) 0); unsigned long val; @@ -278,7 +282,9 @@ static int kvm_psci_0_1_call(struct kvm_vcpu *vcpu) val = PSCI_RET_SUCCESS; break; case KVM_PSCI_FN_CPU_ON: + mutex_lock(&kvm->lock); val = kvm_psci_vcpu_on(vcpu); + mutex_unlock(&kvm->lock); break; case KVM_PSCI_FN_CPU_SUSPEND: case KVM_PSCI_FN_MIGRATE: |