From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:51015) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QFpii-00027M-Qu for qemu-devel@nongnu.org; Fri, 29 Apr 2011 11:35:05 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1QFpih-0000aT-QD for qemu-devel@nongnu.org; Fri, 29 Apr 2011 11:35:04 -0400 Received: from mx1.redhat.com ([209.132.183.28]:12809) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QFpih-0000aB-Hs for qemu-devel@nongnu.org; Fri, 29 Apr 2011 11:35:03 -0400 Date: Fri, 29 Apr 2011 18:34:50 +0300 From: "Michael S. Tsirkin" Message-ID: <20110429153450.GC27816@redhat.com> References: <20110429031437.3796.49456.stgit@s20.home> <20110429150640.GB27816@redhat.com> <4DBAD942.6080001@siemens.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4DBAD942.6080001@siemens.com> Subject: Re: [Qemu-devel] [PATCH] Fix phys memory client - pass guest physical address not region offset List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jan Kiszka Cc: Alex Williamson , qemu-devel@nongnu.org On Fri, Apr 29, 2011 at 05:29:06PM +0200, Jan Kiszka wrote: > On 2011-04-29 17:06, Michael S. Tsirkin wrote: > > On Thu, Apr 28, 2011 at 09:15:23PM -0600, Alex Williamson wrote: > >> When we're trying to get a newly registered phys memory client updated > >> with the current page mappings, we end up passing the region offset > >> (a ram_addr_t) as the start address rather than the actual guest > >> physical memory address (target_phys_addr_t). If your guest has less > >> than 3.5G of memory, these are coincidentally the same thing. If > > I think this broke even with < 3.5G as phys_offset also encodes the > memory type while region_offset does not. So everything became RAMthis > way, no MMIO was announced. > > >> there's more, the region offset for the memory above 4G starts over > >> at 0, so the set_memory client will overwrite it's lower memory entries. > >> > >> Instead, keep track of the guest phsyical address as we're walking the > >> tables and pass that to the set_memory client. > >> > >> Signed-off-by: Alex Williamson > > > > Acked-by: Michael S. Tsirkin > > > > Given all this, can yo tell how much time does > > it take to hotplug a device with, say, a 40G RAM guest? > > Why not collect pages of identical types and report them as one chunk > once the type changes? Sure, but before we bother to optimize this, is this too slow? > Jan > > -- > Siemens AG, Corporate Technology, CT T DE IT 1 > Corporate Competence Center Embedded Linux