From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:40789) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RfBDk-0004pi-L1 for qemu-devel@nongnu.org; Mon, 26 Dec 2011 09:08:09 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1RfBDj-0003kP-Ow for qemu-devel@nongnu.org; Mon, 26 Dec 2011 09:08:08 -0500 Received: from mx1.redhat.com ([209.132.183.28]:21133) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RfBDj-0003k8-E1 for qemu-devel@nongnu.org; Mon, 26 Dec 2011 09:08:07 -0500 Message-ID: <4EF87FB9.6060208@redhat.com> Date: Mon, 26 Dec 2011 16:07:53 +0200 From: Avi Kivity MIME-Version: 1.0 References: <20111204182541.28487.68163.sendpatchset@oc5400248562.ibm.com> <20111204182622.28487.98656.sendpatchset@oc5400248562.ibm.com> <4EEF432A.3030905@redhat.com> <784A6583-DC7F-4EF7-9F07-AAF11F83AA0C@suse.de> <4EEF461E.8000107@siemens.com> In-Reply-To: <4EEF461E.8000107@siemens.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 3/3] QEMU kvm/i386 : Adding KICK_VCPU capability support in i386 target. List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jan Kiszka Cc: Raghavendra K T , "kvm@vger.kernel.org" , "qemu-devel@nongnu.org" , Marcelo Tosatti , Srivatsa Vaddagiri , Alexander Graf , Suzuki Poulose On 12/19/2011 04:11 PM, Jan Kiszka wrote: > >> > >> Backwards compatibility > > > > If we want backwards compatibility, we need more than just a simple feature check, no? Oh, you feed that into CPUID? That's nifty. Ok, so you behave like VMX/SVM do on real hardware - you always expose the functionality but don't list it in CPUID for older user space. > > Do we want this to be on when providing a compat machine type ("pc-0.12" > etc.) to the guest? Then it does need more work (see the dance around > kvmclock). We do. I have a feeling the whole cpuid stuff, paravirt and non-paravirt, needs some fixing in this area. It's different than the normal compat code since not only qemu, but also kvm and the host cpu have a say in what's supported and what's not. -- error compiling committee.c: too many arguments to function