KVM: x86: Loading segments on 64-bit mode may be wrong (2eedcac8) · Commits · 戴 / test

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:

Nadav Amit <namit@cs.technion.ac.il> Signed-off-by:

Paolo Bonzini <pbonzini@redhat.com>

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);
		}

Admin message