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 3/8] KVM: arm64: PSCI: Forbid 64bit functions for 32bit guests
Date: Thu, 23 Apr 2020 16:40:04 +0100 [thread overview]
Message-ID: <20200423154009.4113562-4-maz@kernel.org> (raw)
In-Reply-To: <20200423154009.4113562-1-maz@kernel.org>
Implementing (and even advertising) 64bit PSCI functions to 32bit
guests is at least a bit odd, if not altogether violating the
spec which says ("5.2.1 Register usage in arguments and return values"):
"Adherence to the SMC Calling Conventions implies that any AArch32
caller of an SMC64 function will get a return code of 0xFFFFFFFF(int32).
This matches the NOT_SUPPORTED error code used in PSCI"
Tighten the implementation by pretending these functions are not
there for 32bit guests.
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 | 24 ++++++++++++++++++++++++
1 file changed, 24 insertions(+)
diff --git a/virt/kvm/arm/psci.c b/virt/kvm/arm/psci.c
index 3772717efe3e5..ae364716ee40c 100644
--- a/virt/kvm/arm/psci.c
+++ b/virt/kvm/arm/psci.c
@@ -198,6 +198,21 @@ static void kvm_psci_narrow_to_32bit(struct kvm_vcpu *vcpu)
vcpu_set_reg(vcpu, i, lower_32_bits(vcpu_get_reg(vcpu, i)));
}
+static unsigned long kvm_psci_check_allowed_function(struct kvm_vcpu *vcpu, u32 fn)
+{
+ switch(fn) {
+ case PSCI_0_2_FN64_CPU_SUSPEND:
+ case PSCI_0_2_FN64_CPU_ON:
+ case PSCI_0_2_FN64_AFFINITY_INFO:
+ /* Disallow these functions for 32bit guests */
+ if (vcpu_mode_is_32bit(vcpu))
+ return PSCI_RET_NOT_SUPPORTED;
+ break;
+ }
+
+ return 0;
+}
+
static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu)
{
struct kvm *kvm = vcpu->kvm;
@@ -205,6 +220,10 @@ static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu)
unsigned long val;
int ret = 1;
+ val = kvm_psci_check_allowed_function(vcpu, psci_fn);
+ if (val)
+ goto out;
+
switch (psci_fn) {
case PSCI_0_2_FN_PSCI_VERSION:
/*
@@ -272,6 +291,7 @@ static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu)
break;
}
+out:
smccc_set_retval(vcpu, val, 0, 0, 0);
return ret;
}
@@ -289,6 +309,10 @@ static int kvm_psci_1_0_call(struct kvm_vcpu *vcpu)
break;
case PSCI_1_0_FN_PSCI_FEATURES:
feature = smccc_get_arg1(vcpu);
+ val = kvm_psci_check_allowed_function(vcpu, feature);
+ if (val)
+ break;
+
switch(feature) {
case PSCI_0_2_FN_PSCI_VERSION:
case PSCI_0_2_FN_CPU_SUSPEND:
--
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 ` [PATCH 2/8] KVM: arm64: PSCI: Narrow input registers when using 32bit functions Marc Zyngier
2020-04-23 15:40 ` Marc Zyngier [this message]
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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