Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755431AbbHFLAt (ORCPT ); Thu, 6 Aug 2015 07:00:49 -0400 Received: from mx1.redhat.com ([209.132.183.28]:44212 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755395AbbHFLAr (ORCPT ); Thu, 6 Aug 2015 07:00:47 -0400 From: =?UTF-8?q?Marc=20Mar=C3=AD?= To: linux-kernel@vger.kernel.org, qemu-devel@nongnu.org, seabios@seabios.org Cc: Drew , Stefan Hajnoczi , "Kevin O'Connor" , Gerd Hoffmann , Laszlo , =?UTF-8?q?Marc=20Mar=C3=AD?= Subject: QEMU fw_cfg DMA interface Date: Thu, 6 Aug 2015 13:00:16 +0200 Message-Id: <1438858816-29385-1-git-send-email-markmb@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1294 Lines: 34 Implementation of the FW CFG DMA interface. When running a Linux guest on top of QEMU, using the -kernel options, this is the timing improvement for x86: QEMU commit 2be4f242b50a8 and SeaBIOS commit 908a58c1d5ff QEMU startup time: .078 BIOS startup time: .060 Kernel setup time: .578 Total time: .716 QEMU with this patch series and SeaBIOS with this patch series QEMU startup time: .080 BIOS startup time: .039 Kernel setup time: .002 Total time: .121 QEMU startup time is the time between the start and the first kvm_entry. BIOS startup time is the time between the first kvm_entry and the start of function do_boot, in SeaBIOS. Kernel setup time is the time between the start of the function do_boot in SeaBIOS and the jump to the Linux kernel. As you can see, both the BIOS (because of ACPI tables and other configurations) and the Linux kernel boot (because of the copy to memory) are greatly improved with this new interface. Also, this new interface is an addon to the old interface. Both interfaces are compatible and interchangeable. -- 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/