From 58b7825bc324da55415034a9f6ca5d716b8fd898 Mon Sep 17 00:00:00 2001 From: Gleb Natapov Date: Tue, 11 Dec 2012 15:14:12 +0200 Subject: [PATCH] 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 Signed-off-by: Marcelo Tosatti --- arch/x86/kvm/emulate.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) 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 @@ static int __linearize(struct x86_emulate_ctxt *ctxt, 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)) -- 2.7.4