When instruction decoding begins there could be stale values in the ctxt->memop structure. This causes problems when an instruction is emulated with more op-bytes then the guest wants (like the bsr instruction which is always emulated with 4 or 8 op-bytes). The stale value in this structure causes the unit-test for the bsrw instruction to fail. Initialize the memop.val with 0 to prevent such bugs (an alternative fix could be to always emulate instructions with the number of op-bytes requested by the guest). Signed-off-by: Joerg Roedel <joerg.roedel@xxxxxxx> --- arch/x86/kvm/emulate.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index d4bf50c..1b516ec 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -3937,6 +3937,7 @@ int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len) struct opcode opcode; ctxt->memop.type = OP_NONE; + ctxt->memop.val = 0; ctxt->memopp = NULL; ctxt->_eip = ctxt->eip; ctxt->fetch.start = ctxt->_eip; -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
