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=ham 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 06B88C43381 for ; Mon, 1 Apr 2019 17:24:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C829F20856 for ; Mon, 1 Apr 2019 17:24:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554139467; bh=bo2iXDrUqKVLWiBfTcV5ul7DpcsuaFgj2O6dnC7I6wM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=TW22JjVtB6o1qyBxeEraIpi0uONU8NRDN5N3QgGf5GQ1SlGvlCt4SqMQTpCrIGsrE roCMiFwCyWndZvoCpI7mDGXIZZSOxpQnMg7a543+BqVyqmy/kLyPZb4Qb+Rz3/uUJg MAC6RgMP32BAXT//ThoiiVVVdZw+R5bC/Woh78A8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732256AbfDARY0 (ORCPT ); Mon, 1 Apr 2019 13:24:26 -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: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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: