From: Nadav Amit <namit@cs.technion.ac.il>
Date: Thu, 25 Dec 2014 00:52:23 +0000 (+0200)
Subject: KVM: x86: Access to LDT/GDT that wraparound is incorrect
X-Git-Tag: fixes-v4.0-rc1~113^2~48
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=edccda7ca7e56b335c70ae512f89d0fdf7fb8c69;p=pandora-kernel.git

KVM: x86: Access to LDT/GDT that wraparound is incorrect

When access to descriptor in LDT/GDT wraparound outside long-mode, the address
of the descriptor should be truncated to 32-bit.  Citing Intel SDM 2.1.1.1
"Global and Local Descriptor Tables in IA-32e Mode": "GDTR and LDTR registers
are expanded to 64-bits wide in both IA-32e sub-modes (64-bit mode and
compatibility mode)."

So in other cases, we need to truncate. Creating new function to return a
pointer to descriptor table to avoid too much code duplication.

Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
[Wrap 64-bit check with #ifdef CONFIG_X86_64, to avoid a "right shift count
 >= width of type" warning and consequent undefined behavior. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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