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: sta...@vger.kernel.org
Fixes: acfb3b883f6d ("arm64: KVM: Fix SMCCC handling of unimplemented SMC/HVC
calls")
Signed-off-by: Marc Zyngier <marc.zyng...@arm.com>
---
arch/arm64/kvm/handle_exit.c | 9 +++++++++
1 file changed, 9 insertions(+)
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;
}
--
2.14.2
