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,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 16815C43381 for ; Mon, 1 Apr 2019 18:01:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D034D2084B for ; Mon, 1 Apr 2019 18:01:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554141682; bh=P3xw/PoBaxx0gliOLqBic5NXaK135RaKWxRNJQdb/1s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=mbO24Z+OQIPJ27Y6zuTLYIk5b8T/TiJpzsEc4pl2T6yYU5Oorpf64yexfFwgCh8iO EgUmC/kBnmThsXPhYKNgb5/nyOUPBhlu6rftxs4go72puv/w2wz7880nQGMaV1EcwT SljBwjuEN79qXCx7vNVC1RxGZhSq9ruqP788orjw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729962AbfDARQH (ORCPT ); Mon, 1 Apr 2019 13:16:07 -0400 Received: from mail.kernel.org ([198.145.29.99]:41008 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730975AbfDARQH (ORCPT ); Mon, 1 Apr 2019 13:16:07 -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 F38F420856; Mon, 1 Apr 2019 17:16:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554138966; bh=P3xw/PoBaxx0gliOLqBic5NXaK135RaKWxRNJQdb/1s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=iVGXLaYakhtM5ZzFW3DQ6mkhVCtmtxe2ZW4OQp+auS/6V8eLitWWVi989NZ4mX9XT wRuTCBQMUe8NzudOstODFYdkZ5UfRWa+tg8qGimI6N0YtORyYE2COhEQuKZMIIVhRk FbEWAasCcnDm0Z5pRzrbpfEpY6cpJiCDOaR0oWyA= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Diana Craciun , Michael Ellerman Subject: [PATCH 4.19 035/134] powerpc/fsl: Emulate SPRN_BUCSR register Date: Mon, 1 Apr 2019 19:01:11 +0200 Message-Id: <20190401170048.002495239@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190401170044.243719205@linuxfoundation.org> References: <20190401170044.243719205@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 4.19-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: