Re: [Qemu-devel] [PATCH] linuxboot optionrom: do not jump into loaded kernel in a big real mode

[Alexander Graf]

On 06.01.2013, at 13:56, Gleb Natapov wrote:

> On Sun, Jan 06, 2013 at 01:47:17PM +0100, Alexander Graf wrote:
>> 
>> On 06.01.2013, at 13:36, Gleb Natapov wrote:
>> 
>>> Big real mode is fully emulated by KVM now, so if control is passed to
>>> the loaded kernel while one of the segment registers is in big real
>>> mode all the real mode part of the Linux start up is emulated. This
>>> slows boot process down. Fix that by resetting ES limit to 0xffff before
>>> jumping into the kernel.
>>> 
>>> The patch also removes unused code segment definition from GDT and changes
>>> ES register to be 16bit in protected mode since CS stays 16bit too and
>>> it is CS segment that determines effective operands and addresses length.
>>> 
>>> Signed-off-by: Gleb Natapov <address@hidden>
>> 
>> I assume you tested that things still work, so the changes look ok to me.
>> 
> Loaded kernel with kvm and tcg using -kernel/-initrd.

Good. No objections from my side then.

>> However, this patch should also include a binary patch to 
>> pc-bios/linuxboot.bin, since linuxboot.S doesn't get compiled into the .bin 
>> form on every machine.
>> 
>> 
>> Alex
> OK, something like this?:

Looks like a binary patch, yes :).


Alex