diff options
| author | Andrew Jones <drjones@redhat.com> | 2017-04-18 17:59:58 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-05-20 14:27:00 +0200 |
| commit | cbaeca8251bbe77c646954c7655b661f0fef8170 (patch) | |
| tree | 0e4ec183209b45fa4c982f755d05d73556b8f3fa | |
| parent | 7b268351860c8f9faee86335659118920d7b853b (diff) | |
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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -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 a9b3b905e661..443db0c43d7c 100644 --- a/arch/arm/kvm/psci.c +++ b/arch/arm/kvm/psci.c @@ -208,9 +208,10 @@ 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_get_reg(vcpu, 0) & ~((u32) 0); unsigned long val; + int ret = 1; switch (psci_fn) { case PSCI_0_2_FN_PSCI_VERSION: @@ -230,7 +231,9 @@ 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: @@ -279,6 +282,7 @@ 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_get_reg(vcpu, 0) & ~((u32) 0); unsigned long val; @@ -288,7 +292,9 @@ 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; default: val = PSCI_RET_NOT_SUPPORTED; |