kvm: nVMX: Allow L1 to intercept software exceptions (#BP and #OF)

When L2 exits to L0 due to "exception or NMI", software exceptions
(#BP and #OF) for which L1 has requested an intercept should be
handled by L1 rather than L0. Previously, only hardware exceptions
were forwarded to L1.

Signed-off-by: Jim Mattson <jmattson@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
static int handle_vmptrst(struct kvm_vcpu *vcpu)
{
	unsigned long exit_qualification = vmcs_readl(EXIT_QUALIFICATION);
	u32 vmx_instruction_info = vmcs_read32(VMX_INSTRUCTION_INFO);
	gva_t vmcs_gva;
	struct x86_exception e;

	if (!nested_vmx_check_permission(vcpu))
		return 1;

	if (get_vmx_mem_address(vcpu, exit_qualification,
			vmx_instruction_info, true, &vmcs_gva))
		return 1;
	/* ok to use *_system, as nested_vmx_check_permission verified cpl=0 */
	if (kvm_write_guest_virt_system(&vcpu->arch.emulate_ctxt, vmcs_gva,
				 (void *)&to_vmx(vcpu)->nested.current_vmptr,
				 sizeof(u64), &e)) {
		kvm_inject_page_fault(vcpu, &e);
		return 1;
	}
	nested_vmx_succeed(vcpu);
	return kvm_skip_emulated_instruction(vcpu);
}

static int handle_vmptrst(struct kvm_vcpu *vcpu)
{
	unsigned long exit_qualification = vmcs_readl(EXIT_QUALIFICATION);
	u32 vmx_instruction_info = vmcs_read32(VMX_INSTRUCTION_INFO);
	gva_t vmcs_gva;
	struct x86_exception e;

	if (!nested_vmx_check_permission(vcpu))
		return 1;

	if (get_vmx_mem_address(vcpu, exit_qualification,
			vmx_instruction_info, true, &vmcs_gva))
		return 1;
	/* ok to use *_system, as nested_vmx_check_permission verified cpl=0 */
	if (kvm_write_guest_virt_system(&vcpu->arch.emulate_ctxt, vmcs_gva,
				 (void *)&to_vmx(vcpu)->nested.current_vmptr,
				 sizeof(u64), &e)) {
		kvm_inject_page_fault(vcpu, &e);
		return 1;
	}
	nested_vmx_succeed(vcpu);
	return kvm_skip_emulated_instruction(vcpu);
}
