5.1-stable patches

[thirdparty/kernel/stable-queue.git] / releases / 2.6.32.10 / kvm-x86-emulator-forbid-modifying-cs-segment-register-by-mov-instruction.patch

From 8b9f44140bc4afd2698413cd9960c3912168ee91 Mon Sep 17 00:00:00 2001
From: Gleb Natapov <gleb@redhat.com>
Date: Thu, 18 Feb 2010 12:14:59 +0200
Subject: KVM: x86 emulator: Forbid modifying CS segment register by mov instruction

From: Gleb Natapov <gleb@redhat.com>

commit 8b9f44140bc4afd2698413cd9960c3912168ee91 upstream.

Inject #UD if guest attempts to do so. This is in accordance to Intel
SDM.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 arch/x86/kvm/emulate.c |    6 ++++++
 1 file changed, 6 insertions(+)

--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -1875,6 +1875,12 @@ special_insn:
 		int err;
 
 		sel = c->src.val;
+
+		if (c->modrm_reg == VCPU_SREG_CS) {
+			kvm_queue_exception(ctxt->vcpu, UD_VECTOR);
+			goto done;
+		}
+
 		if (c->modrm_reg == VCPU_SREG_SS)
 			toggle_interruptibility(ctxt, X86_SHADOW_INT_MOV_SS);