KVM: emulator: fix real mode segment checks in address linearization
In real mode CS register is writable, so do not #GP on write.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 39171cb..979869f 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -677,8 +677,9 @@
addr.seg);
if (!usable)
goto bad;
- /* code segment or read-only data segment */
- if (((desc.type & 8) || !(desc.type & 2)) && write)
+ /* code segment in protected mode or read-only data segment */
+ if ((((ctxt->mode != X86EMUL_MODE_REAL) && (desc.type & 8))
+ || !(desc.type & 2)) && write)
goto bad;
/* unreadable code segment */
if (!fetch && (desc.type & 8) && !(desc.type & 2))
