From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:45638) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XnqH7-0001eg-SL for qemu-devel@nongnu.org; Mon, 10 Nov 2014 09:49:07 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XnqH1-0005YU-Ns for qemu-devel@nongnu.org; Mon, 10 Nov 2014 09:49:01 -0500 Message-ID: <5460D056.5010007@suse.de> Date: Mon, 10 Nov 2014 15:48:54 +0100 From: Alexander Graf MIME-Version: 1.0 References: <1415395125-18926-1-git-send-email-agraf@suse.de> <20141110133101.194f5ea0@nial.usersys.redhat.com> <5460BACA.9000702@suse.de> In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] kvm: Fix memory slot page alignment logic List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Maydell Cc: kvm-devel , qemu-stable , Stuart Yoder , QEMU Developers , "qemu-ppc@nongnu.org" , Paolo Bonzini , Igor Mammedov On 10.11.14 14:55, Peter Maydell wrote: > On 10 November 2014 13:16, Alexander Graf wrote: >> Sorry, I don't understand this paragraph. Memory slots in general are >> accelerations for memory access - for MMIO (RAM is usually aligned), KVM >> can always exit to QEMU and just do a manual MMIO exit. > > ...you're a bit stuck if you were hoping to execute code from > that RAM, though, so they're not *purely* acceleration, right? Yes and no. Technically, there's no reason KVM couldn't do an MMIO exit dance to fetch the next instruction. From user space this should be indistinguishable. Today, I don't think it's implemented though :). Alex