From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anthony Liguori Subject: Re: [PATCH] Clean up KVM/QEMU interaction Date: Wed, 30 Jan 2008 08:42:18 -0600 Message-ID: <47A08CCA.8070503@codemonkey.ws> References: <1201646815-5071-1-git-send-email-aliguori@us.ibm.com> <47A047BC.10101@qumranet.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, kvm-ppc-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, Jerone Young , kvm-ia64-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org To: Avi Kivity Return-path: In-Reply-To: <47A047BC.10101-atKUWr5tajBWk0Htik3J/w@public.gmane.org> 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 Avi Kivity wrote: > Anthony Liguori wrote: > >> This patch attempts to clean up the interactions between KVM and QEMU. Sorry >> for such a big patch, but I don't think there's a better way to approach this >> such that it's still bisect friendly. I think this is most of what's needed to >> get basic KVM support into QEMU though. >> >> Right now, there's a mix of #ifdef USE_KVM, if (kvm_allowed), and various >> extern declarations. It's all pretty fugly and there's a lot of mistakes due >> to it. >> >> The following patch eliminates almost all uses of #ifdef USE_KVM by introducing >> a kvm_enabled() macro. If USE_KVM is set, this macro evaluates to kvm_allowed. >> If USE_KVM isn't set, the macro evaluates to 0. >> >> Since GCC eliminates if (0) blocks, this is just as good as using #ifdef. By >> making sure that we never call into libkvm directly from QEMU, we can also just >> not link qemu-kvm when USE_KVM isn't set instead of having the entire file >> wrapped in a USE_KVM. >> >> >> > > It might not when optimizations are disabled. Please test. > I did. It works even without -O. > Also, long term (when we're fully merged into qemu), we need to be able > to build without libkvm or linux/kvm.h installed. With this patch (and the follow-ups), we can build without libkvm. There are only two places we call libkvm directly: in qemu-kvm-*.c or in some blocks guarded with KVM_CAP_* I'll clean up the later with a follow up patch. > That means we can't > use any of the kvm.h defines and data structures. So for example, > kvm_qemu_check_extension(KVM_CAP_USER_MEMORY)) needs to be changed to > kvm_qemu_supports_userspace_memory(). > Every place that makes that sort of call is guarded at the moment so it works. Regards, Anthony Liguori ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/