Il 07/05/2014 06:21, Bandan Das ha scritto:
> + if (rc != X86EMUL_CONTINNUE) > + goto done; > + } > + > while (size--) { > - if (unlikely(ctxt->_eip == fc->end)) { > - rc = do_insn_fetch_bytes(ctxt); > - if (rc != X86EMUL_CONTINUE) > - return rc; > - } > *dest++ = *src++; > ctxt->_eip++; > continue; > @@ -4273,7 +4282,7 @@ int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len) > if (insn_len > 0) > memcpy(ctxt->fetch.data, insn, insn_len); > else { > - rc = do_insn_fetch_bytes(ctxt); > + rc = do_insn_fetch_bytes(ctxt, 1);Is this saying that if the cache is full, then we fetch one more byte ?
No, it is saying that if the instruction is being executed for the first time (we can execute it multiple times if we reenter a repeated instruction after a userspace exit) we try to get at least one byte from RIP. Most of the time, do_insn_fetch_bytes will fetch 15 bytes which are the maximum length of an instruction.
Passing op_size == 1 matches this change in do_insn_fetch_bytes: - if (unlikely(size == 0)) + if (unlikely(size < op_size)) Paolo -- 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
