From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: systemcalls and kvm ...correct me if I am wrong Date: Mon, 08 Jun 2009 15:11:04 +0300 Message-ID: <4A2CFFD8.5070903@redhat.com> References: <4A2B9782.1070503@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org To: Matteo Signorini Return-path: Received: from mx2.redhat.com ([66.187.237.31]:35244 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755023AbZFHMLG (ORCPT ); Mon, 8 Jun 2009 08:11:06 -0400 In-Reply-To: Sender: kvm-owner@vger.kernel.org List-ID: Matteo Signorini wrote: > My doubt is: > will int0x80 from Guest userspace bring me into Guest kernel space or > directly into kvm in the Host kernel? > Like I mentioned, guest kernel. > How can I trigger a jump from Guest to Host kvm at will? > mmio/pio/vmcall > Then the way back from host kernel to guest is via vmenter/vmrun or > must be performed in a different way? > The normal way, vmlaunch/vmresume/vmrun. > thanks in advance, > > Matteo > > 2009/6/7 Avi Kivity : > >> Matteo Signorini wrote: >> >>> Hi to all, >>> >>> correct me if I am wrong but isn't it the following the logical >>> execution chain of a generic system call performed >>> in a Kvm guest? >>> >>> Guest userspace application -> Guest kernel -> Host kernel (kvm) -> >>> Host userspace (Quemu) -> Host kernel -> >>> -> Host userspace (Quemu) -> Guest kernel -> Guest userspace application >>> >>> >>> >> No. The actual path is >> >> guest userspace -> guest kernel -> guest userspace >> >> The guest kernel might access emulated hardware, but usually it does not. >> >> >>> Is there any detailed documentation on how this happens inside qemu-kvm? >>> >>> >> No. >> >> -- >> Do not meddle in the internals of kernels, for they are subtle and quick to >> panic. >> >> >> > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- error compiling committee.c: too many arguments to function