From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38162) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XoF0I-0005l7-3m for qemu-devel@nongnu.org; Tue, 11 Nov 2014 12:13:27 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XoF09-0002Ij-1B for qemu-devel@nongnu.org; Tue, 11 Nov 2014 12:13:18 -0500 Received: from mail-wi0-x234.google.com ([2a00:1450:400c:c05::234]:36613) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XoF08-0002Id-RB for qemu-devel@nongnu.org; Tue, 11 Nov 2014 12:13:08 -0500 Received: by mail-wi0-f180.google.com with SMTP id hi2so2315791wib.1 for ; Tue, 11 Nov 2014 09:13:08 -0800 (PST) Sender: Paolo Bonzini Message-ID: <5462439F.6080401@redhat.com> Date: Tue, 11 Nov 2014 18:13:03 +0100 From: Paolo Bonzini MIME-Version: 1.0 References: <1412607364-14141-1-git-send-email-pbonzini@redhat.com> In-Reply-To: <1412607364-14141-1-git-send-email-pbonzini@redhat.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v2 0/3] Migration-safe ACPI table sizing algorithm List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: mst@redhat.com On 06/10/2014 16:56, Paolo Bonzini wrote: > In the emergency last-minute patches of QEMU 2.1 we did two things: > > - fixed migration problems from 1.7 or 2.0 to 2.1 due to changes in > ACPI table sizes > > - ensured that future versions will not break migration compatibility > with 2.2 for reasonable configurations (with ACPI tables smaller > than a hundred kilobytes, roughly) > > However, this came at the cost of wasting 128 KB unconditionally on > even the smaller configuration, and we didn't provide a mechanism to > ensure compatibility with larger configurations. > > This series provides this mechanism. As mentioned early, the design > is to consider the SSDT immutable and versioned (together with other > non-AML tables such as HPET, TPMA and MADT, SRAT, MCFG, DMAR). > The DSDT instead can change more or less arbitrarily. To do this, > we add padding after the DSDT to allow for future growth (patch 1). > > Once we do this, the size of the ACPI table fw_cfg "file" is constant > given a machine type and a command-line, so we do not need anymore the > larger 128KB padding (patch 2). > > Patch 3 is just cleanups. > > Paolo > > v1->v2: drop linuxboot changes, instead modify the option ROM > in a separate patch > > Paolo Bonzini (3): > pc: introduce new ACPI table sizing algorithm > pc: go back to smaller ACPI tables > pc: clean up pre-2.1 compatibility code > > hw/i386/acpi-build.c | 20 +++++++++++--------- > hw/i386/pc_piix.c | 20 +++++++++++++++++++- > hw/i386/pc_q35.c | 6 ++++-- > include/hw/i386/pc.h | 2 ++ > 4 files changed, 36 insertions(+), 12 deletions(-) > Ping? Paolo