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=-9.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,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 77C73C282DA for ; Mon, 15 Apr 2019 18:46:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4266E2087C for ; Mon, 15 Apr 2019 18:46:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1555353965; bh=YG0VZ+yPFu5nd+JhkVja/Kkw7vW8e/8Nq5N8KNPsWTk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=sg9AJtIaIaU6VdEo9Lt+Euszab9NP5hdNaMcBvE1XdtWjkHD5U+UFe8I5NtStW4l7 I9BWTlSFRTkCS+JC34VjpSo3RCfSdFERfzPQZ7TJIUu0JVldbEyNh+Oeca3QhJ7ezL HF3hxSsAB+pxAxQTrO9BgnXtZnKF8r6kbpfV6Vnk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728512AbfDOSqE (ORCPT ); Mon, 15 Apr 2019 14:46:04 -0400 Received: from mail.kernel.org ([198.145.29.99]:48668 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728511AbfDOSqE (ORCPT ); Mon, 15 Apr 2019 14:46:04 -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 1A2AB2073F; Mon, 15 Apr 2019 18:46:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1555353963; bh=YG0VZ+yPFu5nd+JhkVja/Kkw7vW8e/8Nq5N8KNPsWTk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Q0OueHx/p9yMdXZ54poeSCFFUVOVy5VWknVngcABTd5AE7ucJMufg1MiBPBN/Gn7N 5mG67Ozx83RtK7/XXcR5cAqTWKi0yL7xr9StBxQGT6tgxw5INLwxBgNo6EfSjaL2SL hel09FBacGwfeXgbl7HhF+32+YaI3G6geaLwUsLw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Diana Craciun , Michael Ellerman , Sasha Levin Subject: [PATCH 4.9 35/76] powerpc/fsl: Emulate SPRN_BUCSR register Date: Mon, 15 Apr 2019 20:43:59 +0200 Message-Id: <20190415183716.840557689@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190415183707.712011689@linuxfoundation.org> References: <20190415183707.712011689@linuxfoundation.org> User-Agent: quilt/0.66 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 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: Sasha Levin --- arch/powerpc/kvm/e500_emulate.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/arch/powerpc/kvm/e500_emulate.c b/arch/powerpc/kvm/e500_emulate.c index 990db69a1d0b..fa88f641ac03 100644 --- a/arch/powerpc/kvm/e500_emulate.c +++ b/arch/powerpc/kvm/e500_emulate.c @@ -277,6 +277,13 @@ int kvmppc_core_emulate_mtspr_e500(struct kvm_vcpu *vcpu, int sprn, ulong spr_va 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: -- 2.19.1