From: Marc Zyngier <maz@kernel.org>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Julien Grall" <julien@xen.org>,
kvm@vger.kernel.org, "Suzuki K Poulose" <suzuki.poulose@arm.com>,
"André Przywara" <andre.przywara@arm.com>,
"Christoffer Dall" <christoffer.dall@arm.com>,
"James Morse" <james.morse@arm.com>,
linux-arm-kernel@lists.infradead.org,
"Zenghui Yu" <yuzenghui@huawei.com>,
"Alexandru Elisei" <alexandru.elisei@arm.com>,
kvmarm@lists.cs.columbia.edu,
"Julien Thierry" <julien.thierry.kdev@gmail.com>
Subject: [PATCH 2/8] KVM: arm64: PSCI: Narrow input registers when using 32bit functions
Date: Thu, 23 Apr 2020 16:40:03 +0100 [thread overview]
Message-ID: <20200423154009.4113562-3-maz@kernel.org> (raw)
In-Reply-To: <20200423154009.4113562-1-maz@kernel.org>
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>
---
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 14a162e295a94..3772717efe3e5 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;
--
2.26.2
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next prev parent reply other threads:[~2020-04-23 15:41 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-23 15:40 [GIT PULL] KVM/arm fixes for 5.7, take #1 Marc Zyngier
2020-04-23 15:40 ` [PATCH 1/8] KVM: arm: vgic: Fix limit condition when writing to GICD_I[CS]ACTIVER Marc Zyngier
2020-04-23 15:40 ` Marc Zyngier [this message]
2020-04-23 15:40 ` [PATCH 3/8] KVM: arm64: PSCI: Forbid 64bit functions for 32bit guests Marc Zyngier
2020-04-23 15:40 ` [PATCH 4/8] KVM: arm: vgic: Synchronize the whole guest on GIC{D, R}_I{S, C}ACTIVER read Marc Zyngier
2020-04-23 15:40 ` [PATCH 5/8] KVM: arm: vgic: Only use the virtual state when userspace accesses enable bits Marc Zyngier
2020-04-23 15:40 ` [PATCH 6/8] KVM: arm: vgic-v2: Only use the virtual state when userspace accesses pending bits Marc Zyngier
2020-04-23 15:40 ` [PATCH 7/8] KVM: arm64: vgic-v3: Retire all pending LPIs on vcpu destroy Marc Zyngier
2020-04-23 15:40 ` [PATCH 8/8] KVM: arm64: vgic-its: Fix memory leak on the error path of vgic_add_lpi() Marc Zyngier
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