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Re: [Qemu-devel] [PATCH v3 0/2] future proof rom loading for cross versi
From: |
Laszlo Ersek |
Subject: |
Re: [Qemu-devel] [PATCH v3 0/2] future proof rom loading for cross versiom migration |
Date: |
Mon, 19 Aug 2013 13:37:48 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130806 Thunderbird/17.0.8 |
On 08/13/13 00:43, Michael S. Tsirkin wrote:
> Changes from v2: address comments on v2 by Peter Maydell
> - switch from global constant to function
> - use memory_region_init_ram instead of _ram_ptr
> - disable for 1.6
>
> Changes from v1: address comments by Peter Maydell
> - drop useless data=data line
> - rename target_page_size to migration_page_size to make use clear
> Peter, you also suggested somehow hiding this within memory core.
> I don't see a clean way to do this without lots of code
> changes, I think what I propose here is acceptable for now
> and we can always rework APIs without wire format changes.
>
> Please review, and consider for merging.
>
> Original cover letter below.
>
>
> ROM files that are put in FW CFG are copied to guest ram, by BIOS, but
> they are not backed by RAM so they don't get migrated.
>
> Each time we'll change at least two bytes in such a ROM this will break
> cross-version migration: since we can migrate after BIOS has read the first
> byte but before it has read the second one, getting an inconsistent state.
>
> This patchset makes QEMU future-proof against such changes.
>
> Naturally, this only helps for -M 1.6 and up, older machine types
> will still have the cross-version migration bug.
>
> I think this should be applied for 1.6, this way we won't
> have this problem from 1.7 and on.
>
> Michael S. Tsirkin (2):
> memory: export migration page size
> loader: put FW CFG ROM files into RAM
>
> arch_init.c | 6 ++++++
> hw/core/loader.c | 54
> ++++++++++++++++++++++++++++++++++++++++++++++++---
> hw/i386/pc_piix.c | 2 ++
> hw/i386/pc_q35.c | 2 ++
> include/exec/memory.h | 1 +
> include/hw/loader.h | 1 +
> 6 files changed, 63 insertions(+), 3 deletions(-)
>
Reviewed-by: Laszlo Ersek <address@hidden>
[Qemu-devel] [PATCH v3 2/2] loader: put FW CFG ROM files into RAM, Michael S. Tsirkin, 2013/08/12
Re: [Qemu-devel] [PATCH v3 0/2] future proof rom loading for cross versiom migration, Michael S. Tsirkin, 2013/08/18
Re: [Qemu-devel] [PATCH v3 0/2] future proof rom loading for cross versiom migration,
Laszlo Ersek <=