Re: [Qemu-devel] [PATCH v2 0/3] Migration-safe ACPI table sizing algorithm

[Paolo Bonzini]

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