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

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Message-ID: <C97001BC43954D438ACB059713BA5CDF92040F0F13@USEA-EXCH7.na.uis.unisys.com>
Date:	Fri, 11 Apr 2014 12:51:53 -0500
From:	"Romer, Benjamin M" <Benjamin.Romer@...sys.com>
To:	"H. Peter Anvin" <hpa@...or.com>
CC:	Jet Chen <jet.chen@...el.com>,
	Fengguang Wu <fengguang.wu@...el.com>,
	Paolo Bonzini <pbonzini@...hat.com>,
	Borislav Petkov <bp@...en8.de>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [visorchipset] invalid opcode: 0000 [#1] PREEMPT SMP

On Fri, 2014-04-11 at 10:40 -0700, H. Peter Anvin wrote:
> On 04/11/2014 10:35 AM, Jet Chen wrote:
> > 
> > As Peter said, QEMU probably should *not* set the hypervisor bit. But based on my testing, I think KVM works properly in this case.
> > 
> 
> Either way, unless there is a CPUID interface exposed in CPUID levels
> 0x40000000+, then relying on the hypervisor bit to do VMCALL is wrong in
> the extreme.
> 
> 	-hpa
> 
> 

I'll pass your feedback on to the people who wrote the bad code. Sorry
for the trouble. :)

-- Ben