From: Luca Tettamanti <kronos.it@gmail.com>
Date: Tue, 19 Jun 2007 20:41:20 +0000 (+0200)
Subject: KVM: Fix x86 emulator writeback
X-Git-Tag: v2.6.23-rc1~520^2~16
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=02c03a326a5df825cc01de426f72e160db2b9538;p=pandora-kernel.git

KVM: Fix x86 emulator writeback

When the old value and new one are the same the emulator skips the
write; this is undesirable when the destination is a MMIO area and the
write shall be performed regardless of the previous value. This
optimization breaks e.g. a Linux guest APIC compiled without
X86_GOOD_APIC.

Remove the check and perform the writeback stage in the emulation unless
it's explicitly disabled (currently push and some 2 bytes instructions
may disable the writeback).

Signed-Off-By: Luca Tettamanti <kronos.it@gmail.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
---

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