From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Fri, 12 Jul 2013 13:27:03 +0200 (CEST) Received: from multi.imgtec.com ([194.200.65.239]:30016 "EHLO multi.imgtec.com" rhost-flags-OK-OK-OK-OK) by eddie.linux-mips.org with ESMTP id S6822508Ab3GLL1BC4Crz (ORCPT ); Fri, 12 Jul 2013 13:27:01 +0200 Message-ID: <51DFE7D3.3090002@imgtec.com> Date: Fri, 12 Jul 2013 12:26:11 +0100 From: James Hogan User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130625 Thunderbird/17.0.7 MIME-Version: 1.0 To: linux-mips , Sanjay Lal , Ralf Baechle CC: David Daney , kvm Subject: [PATCH] MIPS: mark KVM_GUEST (T&E KVM) as BROKEN_ON_SMP X-Enigmail-Version: 1.5.1 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-Originating-IP: [192.168.154.65] X-SEF-Processed: 7_3_0_01192__2013_07_12_12_26_54 Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 37287 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: james.hogan@imgtec.com Precedence: bulk List-help: List-unsubscribe: List-software: Ecartis version 1.0.0 List-Id: linux-mips X-List-ID: linux-mips List-subscribe: List-owner: List-post: List-archive: X-list: linux-mips 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