From mboxrd@z Thu Jan  1 00:00:00 1970
From: Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: [PATCH 2/2] KVM: x86 emulator: add XADD instruction emulation
Date: Thu, 12 Aug 2010 11:34:37 -0400
Message-ID: <4C64148D.4080103@redhat.com>
References: <4C63F947.7020808@cn.fujitsu.com> <4C63FA04.3030403@cn.fujitsu.com>
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Cc: Avi Kivity <avi@redhat.com>, kvm@vger.kernel.org
To: Wei Yongjun <yjwei@cn.fujitsu.com>
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On 08/12/2010 09:41 AM, Wei Yongjun wrote:
> +	case 0xc0 ... 0xc1:	/* xadd */
> +		/* Write back the register source. */
> +		write_register_operand(&c->src, c->dst.val, c->dst.bytes);
> +		/* Write back the memory destination with implicit LOCK prefix. */
> +		c->lock_prefix = 1;

It's not a major performance problem, but xadd does _not_ have an
implicit LOCK prefix.

Paolo