From nobody Mon Sep 29 20:17:13 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 61A18C00140 for ; Mon, 15 Aug 2022 21:55:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230366AbiHOVzP (ORCPT ); Mon, 15 Aug 2022 17:55:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43184 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1350293AbiHOVws (ORCPT ); Mon, 15 Aug 2022 17:52:48 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D8447108945; Mon, 15 Aug 2022 12:33:21 -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 ams.source.kernel.org (Postfix) with ESMTPS id 18E2BB80EAC; Mon, 15 Aug 2022 19:33:20 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 45FB5C433C1; Mon, 15 Aug 2022 19:33:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1660591998; bh=wWCgrPVrYdAMVWPaZH24aEPoNQN+KLCiqhuw3uMJlzY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=eQfhVkRhzbwCgGZgjuUS4PJ6em0GfiInftONwVttHiWz0VJyv4j2ykfov6S3cmlwj /YPAhsK1+L/LbE7WsBsM0mQ+9R+kmjIARXHMAbS5tNQ/+d/eMumiDzEC8+pa/tW1Jd L1PYyEise/Sjqwk7EC6Xkar53x8kUDbMMytUAo5k= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, David Woodhouse , Paolo Bonzini Subject: [PATCH 5.19 0042/1157] KVM: x86: do not report preemption if the steal time cache is stale Date: Mon, 15 Aug 2022 19:49:58 +0200 Message-Id: <20220815180441.121490727@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: Paolo Bonzini commit c3c28d24d910a746b02f496d190e0e8c6560224b upstream. Commit 7e2175ebd695 ("KVM: x86: Fix recording of guest steal time / preempted status", 2021-11-11) open coded the previous call to kvm_map_gfn, but in doing so it dropped the comparison between the cached guest physical address and the one in the MSR. This cause an incorrect cache hit if the guest modifies the steal time address while the memslots remain the same. This can happen with kexec, in which case the preempted bit is written at the address used by the old kernel instead of the old one. Cc: David Woodhouse Cc: stable@vger.kernel.org Fixes: 7e2175ebd695 ("KVM: x86: Fix recording of guest steal time / preempt= ed status") Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman --- arch/x86/kvm/x86.c | 2 ++ 1 file changed, 2 insertions(+) --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4635,6 +4635,7 @@ static void kvm_steal_time_set_preempted struct kvm_steal_time __user *st; struct kvm_memslots *slots; static const u8 preempted =3D KVM_VCPU_PREEMPTED; + gpa_t gpa =3D vcpu->arch.st.msr_val & KVM_STEAL_VALID_BITS; =20 /* * The vCPU can be marked preempted if and only if the VM-Exit was on @@ -4662,6 +4663,7 @@ static void kvm_steal_time_set_preempted slots =3D kvm_memslots(vcpu->kvm); =20 if (unlikely(slots->generation !=3D ghc->generation || + gpa !=3D ghc->gpa || kvm_is_error_hva(ghc->hva) || !ghc->memslot)) return;