[Xen-devel] [PATCH] Fix issue with user-mode writes to ro memory

To:	xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject:	[Xen-devel] [PATCH] Fix issue with user-mode writes to ro memory
From:	"Trolle Selander" <trolle.selander@xxxxxxxxx>
Date:	Tue, 29 Jul 2008 12:04:01 +0100
Cc:	Tim Deegan <Tim.Deegan@xxxxxxxxxx>, Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
Delivery-date:	Tue, 29 Jul 2008 04:05:34 -0700
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This patch fixes an issue where a guest could get stuck if a write to memory marked p2m_ram_ro happened from user mode. It would get misinterpreted as a user-mode page-table write, and the "dummy write" emulation necessary to skip over the instruction never got done.
In looking into this, I also discovered that the user-mode page-table check is done in two places, the second (in emulate_map_dest) of which can never be reached and is just a waste of cycles. Tim Deegan requested that rather than completely removing that code, I'd leave it in for debug-builds with an added warning-print.

Signed-off-by: Trolle Selander <trolle.selander@xxxxxxxxxxxxx <mailto:trolle.selander@xxxxxxxxxxxxx>

shadow_user_write_to_ro.patch
Description: Text Data

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[Xen-devel] [PATCH] Fix issue with user-mode writes to ro memory