Commit 0647f4aa authored Dec 12, 2012 by Gleb Natapov

KVM: VMX: relax check for CS register in rmode_segment_valid()



rmode_segment_valid() checks if segment descriptor can be used to enter
vm86 mode. VMX spec mandates that in vm86 mode CS register will be of
type data, not code. Lets allow guest entry with vm86 mode if the only
problem with CS register is incorrect type. Otherwise entire real mode
will be emulated.

Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>

parent 07f42f5f

arch/x86/kvm/vmx.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -3383,6 +3383,8 @@ static bool rmode_segment_valid(struct kvm_vcpu *vcpu, int seg)
		var.dpl = 0x3;
		var.g = 0;
		var.db = 0;
		if (seg == VCPU_SREG_CS)
		var.type = 0x3;
		ar = vmx_segment_access_rights(&var);

		if (var.base != (var.selector << 4))

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