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authorMarc Zyngier <marc.zyngier@arm.com>2018-02-06 17:56:07 +0000
committerCatalin Marinas <catalin.marinas@arm.com>2018-02-06 22:53:52 +0000
commitf5115e8869e1dfafac0e414b4f1664f3a84a4683 (patch)
treef0a24b9245dfa58519e61d7de6b15d5d69331f0e
parent20e8175d246e9f9deb377f2784b3e7dfb2ad3e86 (diff)
arm64: KVM: Increment PC after handling an SMC trap
When handling an SMC trap, the "preferred return address" is set to that of the SMC, and not the next PC (which is a departure from the behaviour of an SMC that isn't trapped). Increment PC in the handler, as the guest is otherwise forever stuck... Cc: stable@vger.kernel.org Fixes: acfb3b883f6d ("arm64: KVM: Fix SMCCC handling of unimplemented SMC/HVC calls") Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
-rw-r--r--arch/arm64/kvm/handle_exit.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c
index 520b0dad3c62..5493bbefbd0d 100644
--- a/arch/arm64/kvm/handle_exit.c
+++ b/arch/arm64/kvm/handle_exit.c
@@ -62,7 +62,16 @@ static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run)
static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run)
{
+ /*
+ * "If an SMC instruction executed at Non-secure EL1 is
+ * trapped to EL2 because HCR_EL2.TSC is 1, the exception is a
+ * Trap exception, not a Secure Monitor Call exception [...]"
+ *
+ * We need to advance the PC after the trap, as it would
+ * otherwise return to the same address...
+ */
vcpu_set_reg(vcpu, 0, ~0UL);
+ kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
return 1;
}

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