From acfb3b883f6d6a4b5d27ad7fdded11f6a09ae6dd Mon Sep 17 00:00:00 2001
From: Marc Zyngier <marc.zyngier@arm.com>
Date: Tue, 16 Jan 2018 10:23:47 +0000
Subject: [PATCH] arm64: KVM: Fix SMCCC handling of unimplemented SMC/HVC calls
KVM doesn't follow the SMCCC when it comes to unimplemented calls,
and inject an UNDEF instead of returning an error. Since firmware
calls are now used for security mitigation, they are becoming more
common, and the undef is counter productive.
Instead, let's follow the SMCCC which states that -1 must be returned
to the caller when getting an unknown function number.
Cc: <stable@vger.kernel.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
---
arch/arm64/kvm/handle_exit.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c
index 304203fa9e330..e60494f1eef9d 100644
--- a/arch/arm64/kvm/handle_exit.c
+++ b/arch/arm64/kvm/handle_exit.c
@@ -45,7 +45,7 @@ static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run)
ret = kvm_psci_call(vcpu);
if (ret < 0) {
- kvm_inject_undefined(vcpu);
+ vcpu_set_reg(vcpu, 0, ~0UL);
return 1;
}
@@ -54,7 +54,7 @@ static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run)
static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run)
{
- kvm_inject_undefined(vcpu);
+ vcpu_set_reg(vcpu, 0, ~0UL);
return 1;
}
--
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