Commit 89efbed0 authored Dec 20, 2012 by Gleb Natapov Committed by Marcelo Tosatti Jan 02, 2013

KVM: VMX: make rmode_segment_valid() more strict.



Currently it allows entering vm86 mode if segment limit is greater than
0xffff and db bit is set. Both of those can cause incorrect execution of
instruction by cpu since in vm86 mode limit will be set to 0xffff and db
will be forced to 0.

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

parent 045a282c

arch/x86/kvm/vmx.c

+1 −3

Original line number	Diff line number	Diff line
		@@ -3341,15 +3341,13 @@ static bool rmode_segment_valid(struct kvm_vcpu *vcpu, int seg)

		vmx_get_segment(vcpu, &var, 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))
		return false;
		if (var.limit < 0xffff)
		if (var.limit != 0xffff)
		return false;
		if (ar != 0xf3)
		return false;

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