qemu-devel
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: AW: Re: [Qemu-devel] VMport patch


From: Anthony Liguori
Subject: Re: AW: Re: [Qemu-devel] VMport patch
Date: Tue, 22 Jan 2008 12:55:13 -0600
User-agent: Thunderbird 2.0.0.6 (X11/20071022)

Alexander Graf wrote:

On Jan 21, 2008, at 3:41 AM, Anthony Liguori wrote:

Mark Williamson wrote:
I think it would be great to maintain compatibility with the binary-only
versions of the vm tools though.

But you're changing the semantics of the x86 instruction set.  You
potentially break a real operating system.  It also eliminates the
possibility of nesting with something like kqemu because you can't trap
all PIO operations.


Maybe have a commandline flag, and have it switched off by default? Or, even better, would be to detect valid vmware tools behaviour and switch it on iff that happened; the default being to behave normally for OSes that aren't running the VMware tools..


There is no way to know for sure that it's vm-tools running. You would have to make use of the cpu option to support it I reckon.


I completely agree with the point of breaking x86 semantics is bad. Yes, it is. What is the point in emulating the VMWare interface though, if the only program actually requiring that interface does not work, namely vmware tools, especially the windows version. So as far as I know VMWare uses VMX to run 64-bit code on Intel as well, so there has to be a way to forcefully break the checks.

vmmouse uses the vmport interface but runs in ring 0 under Linux so it's not an issue. FWIW, the folks on open-vm-tools-devel have expressed an interest in moving to a different interface then their "backdoor" interface.

Regards,

Anthony Liguori

Regards,

Alex

Regards,

Anthony Liguori

Cheers,
Mark


Regards,

Anthony Liguori


Regards,

Alex

----- Urspr√ľngliche Nachricht -----
Von: Anthony Liguori <address@hidden>
Gesendet: Sonntag, 20. Januar 2008 22:40
An: address@hidden
Betreff: Re: [Qemu-devel] VMport patch

Filip Navara wrote:

Hello,

the current version of QEMU emulates the VMware backdoor I/O port and
it works quite well. Unfortunately it doesn't emulate the VMware
behavior of ignoring the I/O permissions when accessing this special
port. The attached patch corrects it. It's important to ignore the
permissions, so that user mode VMware tools can communicate to the
backdoor. =

I really dislike that VMware relies on this.  It's very hard to
implement in kqemu or KVM.  I think it would be better to modify
open-vm-tools than to modify QEMU.

Regards,

Anthony Liguori


Best regards,
Filip Navara
















reply via email to

[Prev in Thread] Current Thread [Next in Thread]