hardware breakpoints do not work withouth hw-v

[hwbpfan]

Hi,

THe title says it already, hardware breakpoints dont work on guest systems, if hw-v features (amd-v, vd-x) are not available or disabled on the host.
If said hardware virtualization features are present and enabled, hwbps work just fine.

This isnt a new issue:

Code: Select all

virtualbox[dot]org/ticket/477

My specs:
host: win7sp1 x64
guest: xpsp3 x86
vbox: 424 (latest)

The issue is very easy to reproduce: just turn turn off hw-v features and try to set a breakpoint.
It appears that this works fine in vmware.

[hwbpfan]

no interest?

this is a very obvious bug.
Where else could i take this?

[mpack]

So, you may need VT-x for this feature. So what? If correct then it would be listed along with all the other things you need VT-x for. I don't see the devs getting bothered about it unless there's a big market for a "fix".

[hwbpfan]

you should not need vt-x for hardware breakpoints to work. HWBPs are in no way related to vt-x.
Instead, an interrupt that should be given to the guest to handle is silently swallowed: a bug.

I don't see the devs getting bothered about it unless there's a big market for a "fix".

This is bug. Any bug should be fixed, regardless of how much damage it causes.

[Perryg]

regardless of how much damage it causes.

While I don't agree at all with this statement, the only way to get something done is to post a ticket at bugtracker Then the DEVs will respond when they have time.

Keep in mind that a virtual machine is by definition not really running on hardware. There are some things that simply can not be done when using a virtual environment, especially if you rip away the component that is used to talk to the hardware.

[hwbpfan]

yes, but this can very well be done (as vmware shows). Hardware Breakpoints are an old, basic and essential part of the x86/x64 architecture.
i would have this bug fixed just for philosophical completeness of the VM.

Heading over to the bugtracker now.

I am really surprised not many people ran into this...

[hwbpfan]

Sorry, but opening duplicate tickets will only increase the load of the developers. The source code is open source available so feel free to submit a patch.

Understandable, but this bug has been known for 5+ years and no one cares.

VmWare it is...