From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46368) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gaLZy-0007Rk-OR for qemu-devel@nongnu.org; Fri, 21 Dec 2018 09:15:07 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gaLZu-0007jH-Ii for qemu-devel@nongnu.org; Fri, 21 Dec 2018 09:15:06 -0500 Received: from mail-wm1-x329.google.com ([2a00:1450:4864:20::329]:35800) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1gaLZu-0007g8-6u for qemu-devel@nongnu.org; Fri, 21 Dec 2018 09:15:02 -0500 Received: by mail-wm1-x329.google.com with SMTP id c126so5857344wmh.0 for ; Fri, 21 Dec 2018 06:15:01 -0800 (PST) References: <76d14474.f850.167cb46b4d9.Coremail.13824125580@163.com> <87d0pw9y7m.fsf@linaro.org> <19e6128e.27e9.167ce041690.Coremail.13824125580@163.com> <874lb79ru9.fsf@linaro.org> <744a1829.ff89.167d091062b.Coremail.13824125580@163.com> From: Alex =?utf-8?Q?Benn=C3=A9e?= In-reply-to: <744a1829.ff89.167d091062b.Coremail.13824125580@163.com> Date: Fri, 21 Dec 2018 14:14:58 +0000 Message-ID: <8736qr9db1.fsf@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] did the qemu can emulate the whole system with the processor that without support the "virtulization and kvm"? List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: tugouxp <13824125580@163.com> Cc: qemu-devel@nongnu.org tugouxp <13824125580@163.com> writes: > thank you. > > i just want to confirm one thing, that is whether the qemu can emulate a= whole operation system just by analysis instructions by instructions manua= lly without the support of KVM. > so from the answer you give to me, it is feasible, right? Yes - if you run qemu-system-$(ARCH) you are emulating a full machine with hardware attached. It can either use TCG or a HW based acceleration like KVM. HW based acceleration is only available on the same machine type. There is a third type - qemu-$(ARCH) which is often called linux-user mode. Here the translation engine only translates instruction from guest to the host and then maps system calls to the host system. This is isn't emulating a whole system but allows you to run binaries from one architecture on another. > > > > thanks very much! > > > > > > > > > > At 2018-12-21 17:01:02, "Alex Benn=C3=A9e" wrote: >> >>tugouxp <13824125580@163.com> writes: >> >>> Hi alex: >>> now my host machine did not have the "/dev/kvm" nodes and no chance= to make it exists. >>> so i want to know whether the "/dev/kvm" is mandatory for qemu to emu= late the whole system. >>> so i can make the emulation without the support of kvm mechanism. >> >>QEMU runs in two modes - full system emulation with TCG doesn't require >>KVM although it is relatively slow. On systems where there guest >>architecture is the same as the host architecture you can run with KMV >>(or HAX/WHPX/HVF) accelerators at near native speeds. >> >>The reasons for not having a /dev/kvm can vary but you haven't said what >>your host architecture is and what OS you are running so it's hard to >>offer advice here. >> >>-- >>Alex Benn=C3=A9e -- Alex Benn=C3=A9e