From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1Kx4Mh-00038W-Ks for qemu-devel@nongnu.org; Mon, 03 Nov 2008 13:41:27 -0500 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1Kx4Me-00036W-Sb for qemu-devel@nongnu.org; Mon, 03 Nov 2008 13:41:26 -0500 Received: from [199.232.76.173] (port=44830 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1Kx4Me-00035k-Hd for qemu-devel@nongnu.org; Mon, 03 Nov 2008 13:41:24 -0500 Received: from wf-out-1314.google.com ([209.85.200.174]:16221) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1Kx4Mb-00080Y-75 for qemu-devel@nongnu.org; Mon, 03 Nov 2008 13:41:21 -0500 Received: by wf-out-1314.google.com with SMTP id 27so2679401wfd.4 for ; Mon, 03 Nov 2008 10:41:18 -0800 (PST) Message-ID: Date: Mon, 3 Nov 2008 20:41:18 +0200 From: "Blue Swirl" Subject: Re: [Qemu-devel] vga optmization In-Reply-To: <5d6222a80811031014r19342d1ex8753d0c6368acc75@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <20081103173111.GC30410@poweredge.glommer> <5d6222a80811031014r19342d1ex8753d0c6368acc75@mail.gmail.com> Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org On 11/3/08, Glauber Costa wrote: > On Mon, Nov 3, 2008 at 4:03 PM, Blue Swirl wrote: > > On 11/3/08, Glauber Costa wrote: > >> Hi guys, > >> > >> this is a port of current kvm vga memory optimization to our new > >> infrastructure proposed by anthony. It's goal is to use as few > >> kvm specific hooks as possible. In fact, the only one I'm relying > >> on is enabling/disabling of logging. The rest, is pretty much general. > >> > >> We map the linear frame buffer area as RAM, and then use dirty tracking > >> to decide whether or not to update it. To be consistent with qemu, > >> this version, differently from upstream kvm, tracks memory based on its > >> physical address, represented by vram_offset, instead of vram_ptr, or > >> any other construct. > >> > >> Let me know what you think > > > > The patch does not apply, because of the kvm files. What patches do I > > need to apply first? I'd like to see how does the optimization apply > > to TCX. > > > Yes, you are missing kvm patches some time ago, which he plans to merge. > > > > This also may mean that some of my comments below can be invalid. > > > >> +void set_vram_mapping(target_phys_addr_t begin, target_phys_addr_t end, ram_addr_t target) > > > > No "static"? > > thanks, will update. > > > > > >> +{ > >> + /* align begin and end address */ > >> + begin = begin & TARGET_PAGE_MASK; > >> + end = begin + VGA_RAM_SIZE; > >> + end = (end + TARGET_PAGE_SIZE -1 ) & TARGET_PAGE_MASK; > > > > This will fail if "end" is at the last page of the memory. > > > How so? I don't think it's possible for the addr 0xsomething0001 to be > valid, but 0x(something+1)000 to be not. 0xfffff001 + 0xfff = 0 (wrapped), then masking still gives 0. > > > >> + uint32_t vga_io_memory; \ > > > > cpu_register_io_memory() returns an "int". > > > can it possibly be negative? > that said, of course I can change it for consistency, but I'd like to > understand it more In case of error it could be negative but I'm only thinking about consistency.