From 827c2ab3314814e1c7d873372c0fe0cad50ba1c5 Mon Sep 17 00:00:00 2001 From: Oliver Upton Date: Tue, 22 Mar 2022 18:35:37 +0000 Subject: [PATCH] KVM: arm64: Actually prevent SMC64 SYSTEM_RESET2 from AArch32 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. Hoist the check to see if the requested function is allowed into kvm_psci_call(), thereby preventing SMC64 calls from AArch32 for all PSCI versions. Fixes: d43583b890e7 ("KVM: arm64: Expose PSCI SYSTEM_RESET2 call to the guest") Acked-by: Will Deacon Reviewed-by: Reiji Watanabe Signed-off-by: Oliver Upton Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20220322183538.2757758-3-oupton@google.com --- arch/arm64/kvm/psci.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/arch/arm64/kvm/psci.c b/arch/arm64/kvm/psci.c index a76d03d50624..faf403a72fdf 100644 --- a/arch/arm64/kvm/psci.c +++ b/arch/arm64/kvm/psci.c @@ -231,10 +231,6 @@ 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: /* @@ -302,7 +298,6 @@ static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu) break; } -out: smccc_set_retval(vcpu, val, 0, 0, 0); return ret; } @@ -422,6 +417,15 @@ static int kvm_psci_0_1_call(struct kvm_vcpu *vcpu) */ int kvm_psci_call(struct kvm_vcpu *vcpu) { + u32 psci_fn = smccc_get_function(vcpu); + unsigned long val; + + val = kvm_psci_check_allowed_function(vcpu, psci_fn); + if (val) { + smccc_set_retval(vcpu, val, 0, 0, 0); + return 1; + } + switch (kvm_psci_version(vcpu)) { case KVM_ARM_PSCI_1_1: return kvm_psci_1_x_call(vcpu, 1); -- 2.39.5