Commit 2890ac99 authored by Marc Zyngier's avatar Marc Zyngier

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: default avatarChristoffer Dall <christoffer.dall@arm.com>
Reviewed-by: default avatarChristoffer Dall <christoffer.dall@arm.com>
Reviewed-by: default avatarAlexandru Elisei <alexandru.elisei@arm.com>
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
parent 8f3d9f35
...@@ -186,6 +186,18 @@ static void kvm_psci_system_reset(struct kvm_vcpu *vcpu) ...@@ -186,6 +186,18 @@ static void kvm_psci_system_reset(struct kvm_vcpu *vcpu)
kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_RESET); 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) static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu)
{ {
struct kvm *kvm = vcpu->kvm; struct kvm *kvm = vcpu->kvm;
...@@ -210,12 +222,16 @@ static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu) ...@@ -210,12 +222,16 @@ static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu)
val = PSCI_RET_SUCCESS; val = PSCI_RET_SUCCESS;
break; break;
case PSCI_0_2_FN_CPU_ON: case PSCI_0_2_FN_CPU_ON:
kvm_psci_narrow_to_32bit(vcpu);
fallthrough;
case PSCI_0_2_FN64_CPU_ON: case PSCI_0_2_FN64_CPU_ON:
mutex_lock(&kvm->lock); mutex_lock(&kvm->lock);
val = kvm_psci_vcpu_on(vcpu); val = kvm_psci_vcpu_on(vcpu);
mutex_unlock(&kvm->lock); mutex_unlock(&kvm->lock);
break; break;
case PSCI_0_2_FN_AFFINITY_INFO: case PSCI_0_2_FN_AFFINITY_INFO:
kvm_psci_narrow_to_32bit(vcpu);
fallthrough;
case PSCI_0_2_FN64_AFFINITY_INFO: case PSCI_0_2_FN64_AFFINITY_INFO:
val = kvm_psci_vcpu_affinity_info(vcpu); val = kvm_psci_vcpu_affinity_info(vcpu);
break; break;
......
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