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KVM: x86: Emulator performs code segment checks on read access 

When read access is performed using a readable code segment, the "conforming"
and "non-conforming" checks should not be done.  As a result, read using
non-conforming readable code segment fails.

This is according to Intel SDM 5.6.1 ("Accessing Data in Code Segments").

The fix is not to perform the "non-conforming" checks if the access is not a
fetch; the relevant checks are already done when loading the segment.

Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Nadav Amit 2014-10-03 01:10:03 +03:00 committed by Paolo Bonzini
parent 0e8a09969a
commit c49c759f7a
1 changed files with 2 additions and 2 deletions
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4
arch/x86/kvm/emulate.c
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@ -703,8 +703,8 @@ static __always_inline int __linearize(struct x86_emulate_ctxt *ctxt,
if (size > *max_size)
goto bad;
cpl = ctxt->ops->cpl(ctxt);
if (!(desc.type & 8)) {
/* data segment */
if (!fetch) {
/* data segment or readable code segment */
if (cpl > desc.dpl)
goto bad;
} else if ((desc.type & 8) && !(desc.type & 4)) {