From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [Qemu-devel] Re: QEMU-KVM and video performance Date: Wed, 12 May 2010 09:39:50 +0300 Message-ID: <4BEA4D36.3020608@redhat.com> References: <4BCEBE5C.4020404@redhat.com> <20100421183357.GK27575@shareable.org> <4BCF6699.2060201@redhat.com> <4BCFF4B5.7010302@redhat.com> <4BE7B6A9.8060007@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: Jamie Lokier , qemu-devel@nongnu.org, kvm@vger.kernel.org To: Gerhard Wiesinger Return-path: Received: from mx1.redhat.com ([209.132.183.28]:27948 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752057Ab0ELGkB (ORCPT ); Wed, 12 May 2010 02:40:01 -0400 In-Reply-To: Sender: kvm-owner@vger.kernel.org List-ID: On 05/12/2010 09:14 AM, Gerhard Wiesinger wrote: > On Mon, 10 May 2010, Avi Kivity wrote: > >> On 05/09/2010 10:35 PM, Gerhard Wiesinger wrote: >>>>> >> >> For 256 color more the first priority is to find out why direct >> mapping is not used. I'd suggest tracing the code that makes this >> decision (in hw/*vga.c) and seeing if it's right or not. > > I think this is because A000 is not initialized for KVM (see log below > and logging patch attached). Why isn't it initialized? Did the guest configure things such as it is impossible to map it directly? Or does the configuration allow direct mapping and qemu incorrectly decides that it cannot direct map? Best would be to print out all the configuration registers and interpret them according to the specification. > > vga_dirty_log_start > vga_dirty_log_start_mapping_lfb_vram_mapped, start=0x000A0000, > len=0x00008000 > BUG: kvm_dirty_pages_log_change: invalid parameters > 00000000000a0000-00000000000a7fff Why does this happen? -- Do not meddle in the internals of kernels, for they are subtle and quick to panic.