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RE: [Xen-devel] [PATCH] ignore guest writes to read only memory regions

To: "Li, Xin" <xin.li@xxxxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: RE: [Xen-devel] [PATCH] ignore guest writes to read only memory regions or memory holes in EPT
From: "Li, Xin" <xin.li@xxxxxxxxx>
Date: Mon, 26 Oct 2009 16:45:48 +0800
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Thread-topic: [Xen-devel] [PATCH] ignore guest writes to read only memory regions or memory holes in EPT
>ignore guest writes to read only memory regions or memory holes in EPT.

Keir,
For reads from memory holes, hw returns a value with all bits set. Xen should
emulate this behavior, and this needs to change Xen x86 instruction emulation
code. do we already have such logic in Xen?

In early days, such reads were sent to Qemu, which returns 0xFFFFFFFF, 0xFFFF
or 0xFF.
Thanks!
-Xin

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