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| author | Marc Zyngier <maz@kernel.org> | 2020-04-01 12:25:05 +0100 |
|---|---|---|
| committer | Marc Zyngier <maz@kernel.org> | 2020-04-17 09:51:45 +0100 |
| commit | 2890ac993daa7bdcc57a92da2f07bcdec243666b (patch) | |
| tree | 3de85579ff6aec6ef51dc586435aa9bb2febc0db | |
| parent | 8f3d9f354286745c751374f5f1fcafee6b3f3136 (diff) | |
| download | linux-2890ac993daa7bdcc57a92da2f07bcdec243666b.tar.bz2 | |
KVM: arm64: PSCI: Narrow input registers when using 32bit functions
When a guest delibarately uses an SMC32 function number (which is allowed),
we should make sure we drop the top 32bits from the input arguments, as they
could legitimately be junk.
Reported-by: Christoffer Dall <christoffer.dall@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@arm.com>
Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
| -rw-r--r-- | virt/kvm/arm/psci.c | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/virt/kvm/arm/psci.c b/virt/kvm/arm/psci.c index 14a162e295a9..3772717efe3e 100644 --- a/virt/kvm/arm/psci.c +++ b/virt/kvm/arm/psci.c @@ -186,6 +186,18 @@ static void kvm_psci_system_reset(struct kvm_vcpu *vcpu) kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_RESET); } +static void kvm_psci_narrow_to_32bit(struct kvm_vcpu *vcpu) +{ + int i; + + /* + * Zero the input registers' upper 32 bits. They will be fully + * zeroed on exit, so we're fine changing them in place. + */ + for (i = 1; i < 4; i++) + vcpu_set_reg(vcpu, i, lower_32_bits(vcpu_get_reg(vcpu, i))); +} + static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu) { struct kvm *kvm = vcpu->kvm; @@ -210,12 +222,16 @@ static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu) val = PSCI_RET_SUCCESS; break; case PSCI_0_2_FN_CPU_ON: + kvm_psci_narrow_to_32bit(vcpu); + fallthrough; 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: + kvm_psci_narrow_to_32bit(vcpu); + fallthrough; case PSCI_0_2_FN64_AFFINITY_INFO: val = kvm_psci_vcpu_affinity_info(vcpu); break; |