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Commit 2eedcac8 authored by Nadav Amit's avatar Nadav Amit Committed by Paolo Bonzini
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KVM: x86: Loading segments on 64-bit mode may be wrong 



The current emulator implementation ignores the high 32 bits of the base in
long-mode.  During segment load from the LDT, the base of the LDT is calculated
incorrectly and may cause the wrong segment to be loaded.

Signed-off-by: default avatarNadav Amit <namit@cs.technion.ac.il>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent e37a75a1

arch/x86/kvm/emulate.c

+4 −2
Original line number Diff line number Diff line
@@ -1358,17 +1358,19 @@ static void get_descriptor_table_ptr(struct x86_emulate_ctxt *ctxt, 
				     u16 selector, struct desc_ptr *dt)

{

	const struct x86_emulate_ops *ops = ctxt->ops;

	u32 base3 = 0;



	if (selector & 1 << 2) {

		struct desc_struct desc;

		u16 sel;



		memset (dt, 0, sizeof *dt);

		if (!ops->get_segment(ctxt, &sel, &desc, NULL, VCPU_SREG_LDTR))

		if (!ops->get_segment(ctxt, &sel, &desc, &base3,

				      VCPU_SREG_LDTR))

			return;



		dt->size = desc_limit_scaled(&desc); /* what if limit > 65535? */

		dt->address = get_desc_base(&desc);

		dt->address = get_desc_base(&desc) | ((u64)base3 << 32);

	} else

		ops->get_gdt(ctxt, dt);

}