From patchwork Fri Aug 18 02:10:52 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Benjamin Herrenschmidt X-Patchwork-Id: 803006 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=kvm-ppc-owner@vger.kernel.org; receiver=) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 3xYRQc4JvCz9t42 for ; Fri, 18 Aug 2017 12:11:20 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753858AbdHRCLT (ORCPT ); Thu, 17 Aug 2017 22:11:19 -0400 Received: from gate.crashing.org ([63.228.1.57]:33064 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753857AbdHRCLT (ORCPT ); Thu, 17 Aug 2017 22:11:19 -0400 Received: from localhost.localdomain (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.13.8) with ESMTP id v7I2Aqt1004389; Thu, 17 Aug 2017 21:10:53 -0500 Message-ID: <1503022252.4493.132.camel@kernel.crashing.org> Subject: [PATCH 1/2] kvm/xive: Workaround P9 DD1.0 bug with IPB bit loss From: Benjamin Herrenschmidt To: kvm-ppc@vger.kernel.org Cc: linuxppc dev list , "kvm@vger.kernel.org" , paulus@samba.org Date: Fri, 18 Aug 2017 12:10:52 +1000 X-Mailer: Evolution 3.24.4 (3.24.4-1.fc26) Mime-Version: 1.0 Sender: kvm-ppc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm-ppc@vger.kernel.org Thankfully it only happens when manually manipulating CPPR which is rather quite rare. Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/kvm/book3s_xive_template.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) -- To unsubscribe from this list: send the line "unsubscribe kvm-ppc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/arch/powerpc/kvm/book3s_xive_template.c b/arch/powerpc/kvm/book3s_xive_template.c index 4636ca6e7d38..150be86b1018 100644 --- a/arch/powerpc/kvm/book3s_xive_template.c +++ b/arch/powerpc/kvm/book3s_xive_template.c @@ -16,7 +16,16 @@ static void GLUE(X_PFX,ack_pending)(struct kvmppc_xive_vcpu *xc) u8 cppr; u16 ack; - /* XXX DD1 bug workaround: Check PIPR vs. CPPR first ! */ + /* + * DD1 bug workaround: If PIPR is less favored than CPPR + * ignore the interrupt or we might incorrectly lose an IPB + * bit. + */ + if (cpu_has_feature(CPU_FTR_POWER9_DD1)) { + u8 pipr = __x_readb(__x_tima + TM_QW1_OS + TM_PIPR); + if (pipr >= xc->hw_cppr) + return; + } /* Perform the acknowledge OS to register cycle. */ ack = be16_to_cpu(__x_readw(__x_tima + TM_SPC_ACK_OS_REG));