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From: Oliver Upton <oupton@google.com>
To: kvmarm@lists.cs.columbia.edu
Cc: kvm@vger.kernel.org, Marc Zyngier <maz@kernel.org>,
	James Morse <james.morse@arm.com>,
	 Alexandru Elisei <alexandru.elisei@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	 linux-arm-kernel@lists.infradead.org,
	Peter Shier <pshier@google.com>,
	 Ricardo Koller <ricarkol@google.com>,
	Reiji Watanabe <reijiw@google.com>,
	 Paolo Bonzini <pbonzini@redhat.com>,
	Will Deacon <will@kernel.org>, Oliver Upton <oupton@google.com>
Subject: [PATCH 2/2] KVM: arm64: Actually prevent SMC64 SYSTEM_RESET2 from AArch32
Date: Fri, 18 Mar 2022 19:38:31 +0000	[thread overview]
Message-ID: <20220318193831.482349-3-oupton@google.com> (raw)
In-Reply-To: <20220318193831.482349-1-oupton@google.com>

The SMCCC does not allow the SMC64 calling convention to be used from
AArch32. While KVM checks to see if the calling convention is allowed in
PSCI_1_0_FN_PSCI_FEATURES, it does not actually prevent calls to
unadvertised PSCI v1.0+ functions.

Check to see if the requested function is allowed from the guest's
execution state. Deny the call if it is not.

Fixes: d43583b890e7 ("KVM: arm64: Expose PSCI SYSTEM_RESET2 call to the guest")
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Oliver Upton <oupton@google.com>
---
 arch/arm64/kvm/psci.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/arm64/kvm/psci.c b/arch/arm64/kvm/psci.c
index cd3ee947485f..0d771468b708 100644
--- a/arch/arm64/kvm/psci.c
+++ b/arch/arm64/kvm/psci.c
@@ -318,6 +318,10 @@ static int kvm_psci_1_x_call(struct kvm_vcpu *vcpu, u32 minor)
 	if (minor > 1)
 		return -EINVAL;
 
+	val = kvm_psci_check_allowed_function(vcpu, psci_fn);
+	if (val)
+		goto out;
+
 	switch(psci_fn) {
 	case PSCI_0_2_FN_PSCI_VERSION:
 		val = minor == 0 ? KVM_ARM_PSCI_1_0 : KVM_ARM_PSCI_1_1;
@@ -378,6 +382,7 @@ static int kvm_psci_1_x_call(struct kvm_vcpu *vcpu, u32 minor)
 		return kvm_psci_0_2_call(vcpu);
 	}
 
+out:
 	smccc_set_retval(vcpu, val, 0, 0, 0);
 	return ret;
 }
-- 
2.35.1.894.gb6a874cedc-goog


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  parent reply	other threads:[~2022-03-18 19:40 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-18 19:38 [PATCH 0/2] KVM: arm64: Fixes for SMC64 SYSTEM_RESET2 calls Oliver Upton
2022-03-18 19:38 ` [PATCH 1/2] KVM: arm64: Generally disallow SMC64 for AArch32 guests Oliver Upton
2022-03-18 19:38 ` Oliver Upton [this message]
2022-03-22  4:41   ` [PATCH 2/2] KVM: arm64: Actually prevent SMC64 SYSTEM_RESET2 from AArch32 Reiji Watanabe
2022-03-22  5:49     ` Oliver Upton
2022-03-22  8:48       ` Marc Zyngier
2022-03-21 14:29 ` [PATCH 0/2] KVM: arm64: Fixes for SMC64 SYSTEM_RESET2 calls Will Deacon
2022-03-22  1:33 ` [PATCH] KVM: arm64: Drop unneeded minor version check from PSCI v1.x handler Oliver Upton

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