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 C5064CCA483 for ; Sat, 23 Jul 2022 10:09:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238601AbiGWKJs (ORCPT ); Sat, 23 Jul 2022 06:09:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43060 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238239AbiGWKIm (ORCPT ); Sat, 23 Jul 2022 06:08:42 -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 3FC7EC5D77; Sat, 23 Jul 2022 03:01:47 -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 8F78161265; Sat, 23 Jul 2022 10:01:47 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 98550C341C0; Sat, 23 Jul 2022 10:01:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1658570507; bh=J9Pf+qzW800PVoLP/QpqWlIKLOEjtqTEYoBrXWnkZow=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=HS3EqPRsi6wiSsidc1u3cZHYAZS/k6BWOvIY1j2u5bUoyHfbvQ9pYyWbMLv1/0hjZ NuXRoBG4ZtZPsLbDPUx7Ha41nYR46mD6wya3Sl+3gfMTioAExzVoj5saUJXj/XX10p uiBoXQKpgV7kFX4C/398B4M2YanE9Khd8PiqOePc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Josh Poimboeuf , "Peter Zijlstra (Intel)" , Borislav Petkov , Thadeu Lima de Souza Cascardo , Ben Hutchings Subject: [PATCH 5.10 121/148] KVM: VMX: Fix IBRS handling after vmexit Date: Sat, 23 Jul 2022 11:55:33 +0200 Message-Id: <20220723095258.204130737@linuxfoundation.org> X-Mailer: git-send-email 2.37.1 In-Reply-To: <20220723095224.302504400@linuxfoundation.org> References: <20220723095224.302504400@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@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: Ben Hutchings 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 @@ -6706,8 +6706,13 @@ 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();