There are LE Linux guests out there that don't handle hypercalls correctly. Instead of interpreting the instruction stream from device tree as big endian they assume it's a little endian instruction stream and fail.
When we see an illegal instruction from such a byte reversed instruction stream, bail out graciously and just declare every hcall as error. Signed-off-by: Alexander Graf <[email protected]> --- arch/powerpc/kvm/book3s_emulate.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/arch/powerpc/kvm/book3s_emulate.c b/arch/powerpc/kvm/book3s_emulate.c index c992447..3f29526 100644 --- a/arch/powerpc/kvm/book3s_emulate.c +++ b/arch/powerpc/kvm/book3s_emulate.c @@ -94,8 +94,25 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run, struct kvm_vcpu *vcpu, int rs = get_rs(inst); int ra = get_ra(inst); int rb = get_rb(inst); + u32 inst_sc = 0x44000002; switch (get_op(inst)) { + case 0: + emulated = EMULATE_FAIL; + if ((kvmppc_get_msr(vcpu) & MSR_LE) && + (inst == swab32(inst_sc))) { + /* + * This is the byte reversed syscall instruction of our + * hypercall handler. Early versions of LE Linux didn't + * swap the instructions correctly and ended up in + * illegal instructions. + * Just always fail hypercalls on these broken systems. + */ + kvmppc_set_gpr(vcpu, 3, EV_UNIMPLEMENTED); + kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4); + emulated = EMULATE_DONE; + } + break; case 19: switch (get_xop(inst)) { case OP_19_XOP_RFID: -- 1.8.1.4 -- To unsubscribe from this list: send the line "unsubscribe kvm-ppc" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
