CPUID mismatch

[okajima]

Assumes you make a snapshot on PC A,
and then you resume it on PC B.

If the CPU of PC A and PC B is differ,
it errors with like "CPUID mismatch".

One solution is "vboxmanage modifyvm --cpuidset".
I tried, but unless you have VT(Vanderpool Technology),
It failed.

Any solution?

The source code tells if you can enable SSMAFTER_DEBUG_IT ,
then the mismatch error is ignored.

How to enable this parameter?

And, another question is , about teleporting.
It needs a source CPU and a dest CPU must be same ?
I mean, if you do teleporting form PC A to PC B,
then you need both CPU must be same?
It is too inconvenient...

Any solution?

--- Okajima, Jun. Tokyo, Japan.
USB booting Windows by VirtualBox.
http://www.chromium.jp/

[Sasquatch]

There is no solution, other than making sure the VM is turned off whenever you create a snapshot you might want to revert to and don't put the VM into saved state whenever you move the VM to another machine. Rule of thumb: an OS doesn't like it when it's CPU is suddenly changed at runtime. You can only move an active VM to another Host if you use Teleport with the setcpuid, which in addition requires shared storage (as only active memory is moved). Since you don't have VT-x or AMD-V, you're stuck with turning off the VM.

[okajima]

Thank you for replying.

This is a general question, but
if CPU changes during suspending,
what happens?

For example, if you run Linux and Apache,
I guess nothing would happen,
because they dont use any special CPU function
like MMX or...

And, if you run Windows and MS Office,
it also does not matter, right?

Of course, if you run multimedia video player,
it fails.

What happens if you change the CPU?
And, is there any way to disable CPU type
checking of VirtualBox?


Okajima, Jun. Tokyo, Japan.
Windows Runs from USB with VirtualBox.
http://www.chromium.jp/

[mpack]

if CPU changes during suspending,what happens?

That really depends on how different the new CPU is, doesn't it? There could be AMD vs Intel differences, 32bit vs 64bit differences, difference in number of cores, differences in implementation of MMX, SSEx etc. No way to really know, hence the CPUID check.

Incidentally, I have no idea why you think that MS Office running on Windows wouldn't care about the CPU. Are you under the impression that only media applications need a CPU? If so then that would be incorrect.

Short summary: shut the VM down properly if you intend to move hosts, take backups - or anything else along those lines.