From mboxrd@z Thu Jan 1 00:00:00 1970 From: James Hogan Subject: [PATCH] MIPS: mark KVM_GUEST (T&E KVM) as BROKEN_ON_SMP Date: Fri, 12 Jul 2013 12:26:11 +0100 Message-ID: <51DFE7D3.3090002@imgtec.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Cc: David Daney , kvm To: linux-mips , Sanjay Lal , Ralf Baechle Return-path: Received: from multi.imgtec.com ([194.200.65.239]:30019 "EHLO multi.imgtec.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932765Ab3GLL04 (ORCPT ); Fri, 12 Jul 2013 07:26:56 -0400 Sender: kvm-owner@vger.kernel.org List-ID: Make KVM_GUEST depend on BROKEN_ON_SMP so that it cannot be enabled with SMP. SMP kernels use ll/sc instructions for an atomic section in the tlb fill handler, with a tlbp instruction contained in the middle. This cannot be emulated with trap & emulate KVM because the tlbp instruction traps and the eret to return to the guest code clears the LLbit which makes the sc instruction always fail. Signed-off-by: James Hogan Cc: Sanjay Lal Cc: Ralf Baechle Cc: David Daney Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org --- arch/mips/Kconfig | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig index 7a58ab9..6a6a096 100644 --- a/arch/mips/Kconfig +++ b/arch/mips/Kconfig @@ -1736,6 +1736,7 @@ endchoice config KVM_GUEST bool "KVM Guest Kernel" + depends on BROKEN_ON_SMP help Select this option if building a guest kernel for KVM (Trap & Emulate) mode -- 1.8.1.2