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Re: [Xen-devel] [PATCH] Calculate correct instruction length for data-fa

To: "Petersson, Mats" <Mats.Petersson@xxxxxxx>
Subject: Re: [Xen-devel] [PATCH] Calculate correct instruction length for data-fault VM exits on VT-x systems
From: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Date: Fri, 28 Apr 2006 10:14:35 +0100
Cc: Khoa Huynh <khoa@xxxxxxxxxx>, xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx>
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On 28 Apr 2006, at 10:02, Petersson, Mats wrote:

I'll look at your previous suggestion of merging the MMIO emulation into x86_emulate later on today. We probably do need to sum up the length and pass it back to the caller - as that code doesn't know how to update the
correct field of the different processor architectures (vmcb vs. vmcs
vs. stack-frame for Para-virtual machine). But it shouldn't be
particularly hard to achieve this.

The emulator uses and updates the eip field of the passed-in regs structure. We may want to change this interface in future by having the caller explicitly pass in a buffer containing the instruction, and the number of valid bytes in the buffer. Or add a 'fetch_insn_byte' callback hook to the emulator interface.

 -- Keir

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