From nobody Mon Sep 29 20:12:04 2025 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 990B9C25B0D for ; Tue, 16 Aug 2022 04:53:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233133AbiHPExQ (ORCPT ); Tue, 16 Aug 2022 00:53:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38878 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232946AbiHPEuA (ORCPT ); Tue, 16 Aug 2022 00:50:00 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 737DB198EF0; Mon, 15 Aug 2022 13:46:29 -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 40A3F61243; Mon, 15 Aug 2022 20:46:29 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2E1F6C433C1; Mon, 15 Aug 2022 20:46:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1660596388; bh=95MZa6uD0zu+Km9ttQRIJ1lsVdf+S8PpnWUB0jn7cXs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tAwdSew95jr40uEjpZnGvsgGr7t7Aj/zMi9tWrE5yBihFNpD/WWmneUuGsGBezrua Fw/0l/Dn9JZGGicZ9QGlcLvH8V0gGoBXQVNNkaeP+jRyyQdOeiwSLpC7ZC9FWcRXju 3N1VMmukO8OYUoX/S7tC4yuYuRP6a7wRoqqTY2ig= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Sean Christopherson , Jim Mattson , Sasha Levin Subject: [PATCH 5.19 1064/1157] KVM: x86: Signal #GP, not -EPERM, on bad WRMSR(MCi_CTL/STATUS) Date: Mon, 15 Aug 2022 20:07:00 +0200 Message-Id: <20220815180522.633495804@linuxfoundation.org> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220815180439.416659447@linuxfoundation.org> References: <20220815180439.416659447@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Sean Christopherson [ Upstream commit 2368048bf5c2ec4b604ac3431564071e89a0bc71 ] Return '1', not '-1', when handling an illegal WRMSR to a MCi_CTL or MCi_STATUS MSR. The behavior of "all zeros' or "all ones" for CTL MSRs is architectural, as is the "only zeros" behavior for STATUS MSRs. I.e. the intent is to inject a #GP, not exit to userspace due to an unhandled emulation case. Returning '-1' gets interpreted as -EPERM up the stack and effecitvely kills the guest. Fixes: 890ca9aefa78 ("KVM: Add MCE support") Fixes: 9ffd986c6e4e ("KVM: X86: #GP when guest attempts to write MCi_STATUS= register w/o 0") Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson Reviewed-by: Jim Mattson Link: https://lore.kernel.org/r/20220512222716.4112548-2-seanjc@google.com Signed-off-by: Sasha Levin --- arch/x86/kvm/x86.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3252,13 +3252,13 @@ static int set_msr_mce(struct kvm_vcpu * */ if ((offset & 0x3) =3D=3D 0 && data !=3D 0 && (data | (1 << 10) | 1) !=3D ~(u64)0) - return -1; + return 1; =20 /* MCi_STATUS */ if (!msr_info->host_initiated && (offset & 0x3) =3D=3D 1 && data !=3D 0) { if (!can_set_mci_status(vcpu)) - return -1; + return 1; } =20 vcpu->arch.mce_banks[offset] =3D data;