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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 78C02C433F5 for ; Wed, 5 Oct 2022 11:35:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230123AbiJELfH (ORCPT ); Wed, 5 Oct 2022 07:35:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36320 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230084AbiJELeW (ORCPT ); Wed, 5 Oct 2022 07:34:22 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9894674B82; Wed, 5 Oct 2022 04:33:47 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 1460361645; Wed, 5 Oct 2022 11:33:46 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1FF47C433D7; Wed, 5 Oct 2022 11:33:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1664969625; bh=XkPzfNyPowbMi3mS7dxk8n8qdgd2wl7+MFrrgQeIweo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ua7qo0WLoo4tQ5V4gsDgs13s2Lb/wdPaYR4R4Hnllmd5ZHyeqF1kVzPL/FR6QxclW 1FDoq2icwSrdi4R37nkDOtJici0ayto2Tzb5issBSfctwGjsX4ljAQ3n5zr4euitZM akgLzGS7XkFiTkGT8sPmfSDSkQcAihYrc4MOVBS4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , Josh Poimboeuf , "Peter Zijlstra (Intel)" , Borislav Petkov , Thadeu Lima de Souza Cascardo Subject: [PATCH 5.4 29/51] KVM: VMX: Fix IBRS handling after vmexit Date: Wed, 5 Oct 2022 13:32:17 +0200 Message-Id: <20221005113211.618592607@linuxfoundation.org> X-Mailer: git-send-email 2.38.0 In-Reply-To: <20221005113210.255710920@linuxfoundation.org> References: <20221005113210.255710920@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Josh Poimboeuf commit bea7e31a5caccb6fe8ed989c065072354f0ecb52 upstream. For legacy IBRS to work, the IBRS bit needs to be always re-written after vmexit, even if it's already on. Signed-off-by: Josh Poimboeuf Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Borislav Petkov Signed-off-by: Thadeu Lima de Souza Cascardo Signed-off-by: Greg Kroah-Hartman --- arch/x86/kvm/vmx/vmx.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -6571,8 +6571,13 @@ void noinstr vmx_spec_ctrl_restore_host( /* * If the guest/host SPEC_CTRL values differ, restore the host value. + * + * For legacy IBRS, the IBRS bit always needs to be written after + * transitioning from a less privileged predictor mode, regardless of + * whether the guest/host values differ. */ - if (vmx->spec_ctrl != hostval) + if (cpu_feature_enabled(X86_FEATURE_KERNEL_IBRS) || + vmx->spec_ctrl != hostval) native_wrmsrl(MSR_IA32_SPEC_CTRL, hostval); barrier_nospec();