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authorMarc Zyngier <maz@kernel.org>2020-04-01 12:25:05 +0100
committerMarc Zyngier <maz@kernel.org>2020-04-17 09:51:45 +0100
commit2890ac993daa7bdcc57a92da2f07bcdec243666b (patch)
tree3de85579ff6aec6ef51dc586435aa9bb2febc0db /virt
parent8f3d9f354286745c751374f5f1fcafee6b3f3136 (diff)
downloadlinux-2890ac993daa7bdcc57a92da2f07bcdec243666b.tar.gz
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>
Diffstat (limited to 'virt')
-rw-r--r--virt/kvm/arm/psci.c16
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;