From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A7BFBC10F05 for ; Mon, 1 Apr 2019 17:54:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 73A4F2084B for ; Mon, 1 Apr 2019 17:54:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554141274; bh=bo2iXDrUqKVLWiBfTcV5ul7DpcsuaFgj2O6dnC7I6wM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=nFYuBb3FzzY++TKbb6sCJ3rbP5Bpi60eUrmypA2ZNBwHXgQYMyKMCaa/x3wV+71DE UyBi9lclOGvxn8Jo0Mpre4Kzz6/sHlcgSlyGUE22lMJgMUODyriRoKb9vg5ePcLF1s BRIw9/dMSqQBVUi/3out05RfWDLG06KmjVaipZyY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731875AbfDARYZ (ORCPT ); Mon, 1 Apr 2019 13:24:25 -0400 Received: from mail.kernel.org ([198.145.29.99]:54880 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731851AbfDARYY (ORCPT ); Mon, 1 Apr 2019 13:24:24 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 2F3DE20856; Mon, 1 Apr 2019 17:24:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554139463; bh=bo2iXDrUqKVLWiBfTcV5ul7DpcsuaFgj2O6dnC7I6wM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CHRWN0K/ReP+s3X5AzDAaWin9eNvHhtHU/shcqhMie8jkS0fV/162b9LIR7nvm6Un rNLFPosrqwPGLVt++yfVb+Z3Mx9GnkTxP6W8TrWtnktNGi6384awrn7ULJfle77K2f m4b6RAQ/Wv6GSPzW9VTQu9RKQuHPLO4Or61VuJvg= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Diana Craciun , Michael Ellerman Subject: [PATCH 4.14 046/107] powerpc/fsl: Emulate SPRN_BUCSR register Date: Mon, 1 Apr 2019 19:02:01 +0200 Message-Id: <20190401170050.025388369@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190401170045.246405031@linuxfoundation.org> References: <20190401170045.246405031@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Diana Craciun commit 98518c4d8728656db349f875fcbbc7c126d4c973 upstream. In order to flush the branch predictor the guest kernel performs writes to the BUCSR register which is hypervisor privilleged. However, the branch predictor is flushed at each KVM entry, so the branch predictor has been already flushed, so just return as soon as possible to guest. Signed-off-by: Diana Craciun [mpe: Tweak comment formatting] Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman --- arch/powerpc/kvm/e500_emulate.c | 7 +++++++ 1 file changed, 7 insertions(+) --- a/arch/powerpc/kvm/e500_emulate.c +++ b/arch/powerpc/kvm/e500_emulate.c @@ -277,6 +277,13 @@ int kvmppc_core_emulate_mtspr_e500(struc vcpu->arch.pwrmgtcr0 = spr_val; break; + case SPRN_BUCSR: + /* + * If we are here, it means that we have already flushed the + * branch predictor, so just return to guest. + */ + break; + /* extra exceptions */ #ifdef CONFIG_SPE_POSSIBLE case SPRN_IVOR32: