4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Mark Rutland <mark.rutland@xxxxxxx> From: Marc Zyngier <marc.zyngier@xxxxxxx> commit f5115e8869e1dfafac0e414b4f1664f3a84a4683 upstream. 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@xxxxxxxxxxxxxxx Fixes: acfb3b883f6d ("arm64: KVM: Fix SMCCC handling of unimplemented SMC/HVC calls") Reviewed-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx> Tested-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx> Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx> Signed-off-by: Mark Rutland <mark.rutland@xxxxxxx> [v4.9 backport] Tested-by: Greg Hackmann <ghackmann@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/arm64/kvm/handle_exit.c | 9 +++++++++ 1 file changed, 9 insertions(+) --- a/arch/arm64/kvm/handle_exit.c +++ b/arch/arm64/kvm/handle_exit.c @@ -53,7 +53,16 @@ static int handle_hvc(struct kvm_vcpu *v 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; }