From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anthony Liguori Subject: Re: vmcall time Date: Sun, 11 Mar 2007 12:02:41 -0500 Message-ID: <45F43631.3060703@codemonkey.ws> References: <45F33DB7.8090907@codemonkey.ws> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org To: Omar Khan Return-path: In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: kvm.vger.kernel.org Omar Khan wrote: > Anthony Liguori writes: > > >> I've got a patch that should appear in virtbench soon that actually >> measures vmcall latency. >> >> http://ozlabs.org/~rusty/virtbench >> >> > > Thanks Anthony. I have a newbie question though. In the vmcall function in the > patch: > > +static int vmcall(unsigned int cmd) > +{ > + signal(SIGILL, illegal_instruction); > + asm volatile(".byte 0x0F,0x01,0xC1,0xC3\n" ::"a"(cmd)); > + signal(SIGILL, SIG_DFL); > + > + return 0; > +} > > Why do you have the ret opcode '0xC3' with the vmcall? > Because I lazily copied from KVM instead of looking them up. I figured 0xC3 was a NOP. Will fix. > Thanks > > Omar > > > ------------------------------------------------------------------------- > Take Surveys. Earn Cash. Influence the Future of IT > Join SourceForge.net's Techsay panel and you'll get the chance to share your > opinions on IT & business topics through brief surveys-and earn cash > http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV > _______________________________________________ > kvm-devel mailing list > kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org > https://lists.sourceforge.net/lists/listinfo/kvm-devel > > ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV