From: Marc Zyngier <maz@kernel.org>
To: linux-arm-kernel@lists.infradead.org,
kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org
Cc: James Morse <james.morse@arm.com>,
Christoffer Dall <christoffer.dall@arm.com>,
Julien Thierry <julien.thierry.kdev@gmail.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>
Subject: [PATCH 1/2] KVM: arm64: PSCI: Narrow input registers when using 32bit functions
Date: Wed, 1 Apr 2020 17:58:15 +0100 [thread overview]
Message-ID: <20200401165816.530281-2-maz@kernel.org> (raw)
In-Reply-To: <20200401165816.530281-1-maz@kernel.org>
When a guest delibarately uses an SSMC32 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>
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
virt/kvm/arm/psci.c | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
diff --git a/virt/kvm/arm/psci.c b/virt/kvm/arm/psci.c
index 17e2bdd4b76f..69ff4a51ceb5 100644
--- a/virt/kvm/arm/psci.c
+++ b/virt/kvm/arm/psci.c
@@ -187,6 +187,18 @@ 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, (u32)vcpu_get_reg(vcpu, i));
+}
+
static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu)
{
struct kvm *kvm = vcpu->kvm;
@@ -211,12 +223,16 @@ 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;
--
2.25.0
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next prev parent reply other threads:[~2020-04-01 16:58 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-01 16:58 [PATCH 0/2] KVM: arm64: PSCI fixes Marc Zyngier
2020-04-01 16:58 ` Marc Zyngier [this message]
2020-04-02 13:47 ` [PATCH 1/2] KVM: arm64: PSCI: Narrow input registers when using 32bit functions Christoffer Dall
2020-04-03 14:02 ` Alexandru Elisei
2020-04-01 16:58 ` [PATCH 2/2] KVM: arm64: PSCI: Forbid 64bit functions for 32bit guests Marc Zyngier
2020-04-02 13:48 ` Christoffer Dall
2020-04-03 14:02 ` Alexandru Elisei
2020-04-03 10:35 ` [PATCH 0/2] KVM: arm64: PSCI fixes Alexandru Elisei
2020-04-03 11:20 ` Marc Zyngier
2020-04-03 14:01 ` Alexandru Elisei
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