linux-kernel - Re: VMware, x86

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Message-ID: <m1slacu88z.fsf@ebiederm.dsl.xmission.com>
Date:	Fri, 04 May 2007 05:40:44 -0600
From:	ebiederm@...ssion.com (Eric W. Biederman)
To:	Petr Vandrovec <petr@...are.com>
Cc:	nigel@...el.suspend2.net, Arjan van de Ven <arjan@...radead.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: VMware, x86_64 and 2.6.21.

Petr Vandrovec <petr@...are.com> writes:

> Nigel Cunningham wrote:
>> Hi Arjan.
>>
>> On Tue, 2007-05-01 at 07:57 -0700, Arjan van de Ven wrote:
>>> On Tue, 2007-05-01 at 15:42 +1000, Nigel Cunningham wrote:
>>>> Hi.
>>>>
>>>> Does anyone have VMware working on x86_64 with 2.6.21? It's working fine
>>>> for me with 2.6.20, but freezes the whole computer with 2.6.21. Before I
>>>> start a git-bisect, I thought I might ask if anyone knew of some
>>>> compilation option I might have missed.
>>>
>>> if you want to ask questions about proprietary kernel stuff you're
>>> better off asking the vendor directly, not lkml
>>
>> I did, but given that it the failure only appeared with a change of
>> vanilla kernel version, I didn't think it was out of place to ask here
>> too.
>
> I thought I already talked about that on VMware's forums, but apparently I just
> discussed it in email only.  Culprit (if I can say that) is
> http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=610142927b5bc149da92b03c7ab08b8b5f205b74
>
> It changed interrupt layout - before that change IRQ 0-15 were using vectors
> 0x20-0x2F, after change they use interrupts 0x30-0x3F.  Which has unfortunate
> effect that when hardware IRQ 8 arrives while VM is running, vmm believes that
> it internally used 'INT 0x38' to call some hypervisor service - and (1) hardware
> interrupt is never acknowledged, and (2) hypervisor issues random operation
> depending on contents of registers at the time interrupt arrived.  Both are
> quite bad, and usual result is that VMware panics, and while writing core dump
> kernel hangs as IOAPIC believes that there is IRQ 8 in service, and so it does
> not ever deliver IRQs 14/15 for legacy IDE harddisks (which are at same level).
>
> One of possible fixes (if you need to run older products than VMware Workstation
> 6 on 64bit 2.6.21+) is replacing
>
> #define IRQ0_VECTOR            FIRST_EXTERNAL_VECTOR + 0x10
>
> with
>
> #define IRQ0_VECTOR            FIRST_EXTERNAL_VECTOR + 0x08

Nope.  That will break irq migration don't even think about it.

> Then IRQ 0x38 will be skipped.  Other option is move only IRQ8_VECTOR somewhere
> else (into 0x21-0x2F range).
> 							Petr Vandrovec
>
> P.S.: Well, and obviously this has nothing to do with vmmon...

I don't even want to think about how a kernel module gets far enough
into the kernel to be affected by our vector layout.  These are internal
implementation details, without anything exported to modules.

Can I please see the source of the code in vmware that is doing this?

Eric
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