From: Paolo Bonzini <pbonzini@redhat.com>
To: Jidong Xiao <jidong.xiao@gmail.com>, KVM <kvm@vger.kernel.org>
Subject: Re: Question about the kvm emulator
Date: Thu, 22 May 2014 13:42:06 +0200 [thread overview]
Message-ID: <537DE28E.7040900@redhat.com> (raw)
In-Reply-To: <CAG4AFWanoyXTt82yNvJQyNRExc2qX9vxgO6M-2dhkEyZMKWi7Q@mail.gmail.com>
Il 22/05/2014 05:55, Jidong Xiao ha scritto:
> Hi,
>
> I noticed that there is a file call emulate.c, under the directory of
> arch/x86/kvm/, in its header part, it says:
>
> "Generic x86 (32-bit and 64-bit) instruction decoder and emulator."
>
> I am confused about this, since qemu will be the emulator, why does
> kvm itself also includes such an emulator? In particular, I added some
> printk debug statement in x86_emulate_insn() and
> emulate_instruction(), but I never see them being invoked. Can someone
> kindly explain this, thank you!
QEMU is providing the device model and interfaces with KVM. QEMU's CPU
emulation functionality is not used when running with KVM.
The KVM emulator is used: 1) to execute instructions that read or write
to device memory; 2) to run "big real mode" programs on microprocessors
that do not support it natively, for example Intel processors older than
Westmere.
Paolo
next prev parent reply other threads:[~2014-05-22 11:42 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-22 3:55 Question about the kvm emulator Jidong Xiao
2014-05-22 11:42 ` Paolo Bonzini [this message]
2014-05-23 2:24 ` Jidong Xiao
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