Re: [visorchipset] invalid opcode: 0000 [#1] PREEMPT SMP

[H. Peter Anvin]

On 04/09/2014 04:01 PM, Fengguang Wu wrote:
> CC the KVM people: it looks like a KVM problem that can be triggered by
> 
>         qemu-system-x86_64 -cpu Haswell,+smep,+smap

I'm really confused.  First of all, is this a KVM problem or is it a
Qemu JIT problem?

Either seems really wonky.  It is questionable at best whether or not
Qemu in JIT mode should set the hypervisor bit IMO.  However, even so,
you *better* not call VMCALL *just* because the hypervisor bit is set.

The reason for it is that you have absolutely no idea what VMCALL is
going to do on any one hypervisor... different hypervisors even use
completely different conventions for VMCALL, and some might not accept
VMCALL at all and might just terminate your guest with extreme prejudice.

So what is actually going on here?

	-hpa

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