3.16.57-rc1 review patch. If anyone has any objections, please let me know.
------------------
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...
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>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
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
@@ -43,7 +43,16 @@ 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_reg(vcpu, 0) = ~0UL;
+ kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
return 1;
}
