From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:57179) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XrKrm-0006Jp-RW for qemu-devel@nongnu.org; Thu, 20 Nov 2014 01:05:28 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XrKrd-0007rI-HR for qemu-devel@nongnu.org; Thu, 20 Nov 2014 01:05:18 -0500 Received: from mail-wi0-x235.google.com ([2a00:1450:400c:c05::235]:45763) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XrKrd-0007r2-BP for qemu-devel@nongnu.org; Thu, 20 Nov 2014 01:05:09 -0500 Received: by mail-wi0-f181.google.com with SMTP id r20so4168815wiv.14 for ; Wed, 19 Nov 2014 22:05:08 -0800 (PST) Sender: Paolo Bonzini Message-ID: <546D8491.2010000@redhat.com> Date: Thu, 20 Nov 2014 07:05:05 +0100 From: Paolo Bonzini MIME-Version: 1.0 References: <1412607364-14141-1-git-send-email-pbonzini@redhat.com> <5462439F.6080401@redhat.com> In-Reply-To: <5462439F.6080401@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 11/11/2014 18:13, Paolo Bonzini wrote: > > > 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? Ping?? Paolo