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 F11FFC43381 for ; Mon, 1 Apr 2019 17:16:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B94FF20856 for ; Mon, 1 Apr 2019 17:16:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554138970; bh=P3xw/PoBaxx0gliOLqBic5NXaK135RaKWxRNJQdb/1s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=LGKxOlwdaAMQHR35iXTjKyWeNptgFKK9etx1r0iSmgNrABeU1QnVzr6BkER33AqGa Y6JpFFWrrUBC3vsV2LuA1l4wyd17+UZzmZN0p2XNB0IhZDIg4v0vI7QeAwIXC9Z8Cb ReSS1EAyNY0TmR0SurLBfQwVYjdqBsr0JjW8Fhps= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730989AbfDARQJ (ORCPT ); Mon, 1 Apr 2019 13:16:09 -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: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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: