linux-kernel - Re: [PATCH 9/9] KVM: x86: smsw emulation is incorrect in 64-bit mode

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Message-ID: <539086F6.8000004@zytor.com>
Date:	Thu, 05 Jun 2014 08:04:22 -0700
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Nadav Amit <nadav.amit@...il.com>,
	Paolo Bonzini <pbonzini@...hat.com>
CC:	Nadav Amit <namit@...technion.ac.il>, gleb@...nel.org,
	tglx@...utronix.de, mingo@...hat.com, x86@...nel.org,
	kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 9/9] KVM: x86: smsw emulation is incorrect in 64-bit mode

On 06/05/2014 08:02 AM, Nadav Amit wrote:
>> I'm sorry, I'm missing the place where 64-bit mode is taken into account?
> It is not, since on 32-bit mode the high-order 16 bits of a register destination are undefined. 
> If I recall correctly, in this case the high-order 16-bits on native
system actually reflect the high-order 16-bits of CR0.

This sounds like something that really should be verified
experimentally.  The above claim seems... odd.

	-hpa


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