Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755443Ab3HZB0p (ORCPT ); Sun, 25 Aug 2013 21:26:45 -0400 Received: from usmamail.tilera.com ([12.216.194.151]:24593 "EHLO USMAMAIL.TILERA.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754509Ab3HZB0o (ORCPT ); Sun, 25 Aug 2013 21:26:44 -0400 Message-ID: <521AAED7.4080407@tilera.com> Date: Sun, 25 Aug 2013 21:26:47 -0400 From: Chris Metcalf User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:17.0) Gecko/20130801 Thunderbird/17.0.8 MIME-Version: 1.0 To: Gleb Natapov CC: , , Paolo Bonzini , Jan Kiszka Subject: Re: [PATCH v2] tile: support KVM for tilegx References: <52091682.8020004@siemens.com> <201308122037.r7CKbo99011833@farm-0021.internal.tilera.com> <20130825113953.GN8218@redhat.com> In-Reply-To: <20130825113953.GN8218@redhat.com> X-Enigmail-Version: 1.5.2 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1975 Lines: 34 On 8/25/2013 7:39 AM, Gleb Natapov wrote: > On Mon, Aug 12, 2013 at 04:24:11PM -0400, Chris Metcalf wrote: >> This change provides the initial framework support for KVM on tilegx. >> Basic virtual disk and networking is supported. >> > This needs to be broken down to more reviewable patches. I already broke out one pre-requisite patch that wasn't strictly KVM-related: https://lkml.org/lkml/2013/8/12/339 In addition, we've separately arranged to support booting our kernels in a way that is compatible with the Tilera booter running at the highest privilege level, which enables multiple kernel privilege levels: https://lkml.org/lkml/2013/5/2/468 How would you recommend further breaking down this patch? It's pretty much just the basic support for minimal KVM. I suppose I could break out all the I/O related stuff into a separate patch, though it wouldn't amount to much; perhaps the console could also be broken out separately. Any other suggestions? > Also can you > describe the implementation a little bit? Does tile arch has vitalization > extension this implementation uses, or is it trap and emulate approach? > If later does it run unmodified guest kernels? What userspace are you > using with this implementation? We could do full virtualization via trap and emulate, but we've elected to do a para-virtualized approach. Userspace runs at PL (privilege level) 0, the guest kernel runs at PL1, and the host runs at PL2. We have available per-PL resources for various things, and take advantage of having two on-chip timers (for example) to handle timing for the host and guest kernels. We run the same userspace with either the host or the guest. -- Chris Metcalf, Tilera Corp. http://www.tilera.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/