Re: [Xen-devel] about vmxassist

[Keir Fraser <keir.fraser@xxxxxxxxxxxxx>]

Yes, that's why it replaces vmxassist! It more accurately simulates the
real-mode environment than vmxassist was able to, hence more real-mode code
runs correctly under full emulation (e.g., a wider range of bootloaders).

 -- Keir

On 8/3/08 16:55, "yushang" <yusunn@xxxxxxxxx> wrote:

> Thanks . I see . It seems the real-mode emulator is more advanced than
> vmxassist ?
> 
> 2008/3/9, Keir Fraser <keir.fraser@xxxxxxxxxxxxx>:
>> On 8/3/08 07:11, "yushang" <yusunn@xxxxxxxxx> wrote:
>> 
>>>>> I find the code path
>>>>> will enter the native real mode if do not use vmxassist , not a
>>>>> emulation one .
>>> Sorry but I mean the code path of hvmloader , just at the beginning of
>>> hvmloader, if do not use vmxassist execution will return from main and
>>> enter real-address mode then jmp to bios , so bios will run in
>>> real-address mode , is this true ?
>> 
>> 
>> Yes, as soon as real mode is entered (CR0 bit 0 is cleared) Xen notices that
>>  and runs the guest through the full real-mode emulator until CR0 bit 0 is
>>  set again.
>> 
>> 
>>   -- Keir
>> 
>> 
>> 



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