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 98236C433EF for ; Tue, 1 Mar 2022 20:14:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237723AbiCAUPJ (ORCPT ); Tue, 1 Mar 2022 15:15:09 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47384 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237704AbiCAUPE (ORCPT ); Tue, 1 Mar 2022 15:15:04 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1B76375C09; Tue, 1 Mar 2022 12:14:17 -0800 (PST) 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 7F1916153D; Tue, 1 Mar 2022 20:14:16 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DC7D5C340EF; Tue, 1 Mar 2022 20:14:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1646165655; bh=e4+k2tKjzJN7Ut/f1DWjK/yhchOSBsfcblRGojV9NpQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RAdzHxNAkw2jHcgyNLO0Ln2htIkTIPIijysB7GMLAkukI0bktPNubu8WYOue3yeyb c2BtgyBjEuEmN2SUePtZsFtwA51mlqyxLxRak0NRx511qioNRA3mM+FR2ZafD2dL6w /s3gmRMaIBtnH5Ceef2WL0d4nRUJt0llMrDKT9WsjbH+GUZCHuFFMiC3JNn26dTmi6 xQSxTgp7v5tF1nCpCeVzbQBWSFfQvwiCI+QogwEOIiZmB/Phz8MWXZqc2gfE2kOfLw LxK4k1vz6NBBM+i6O9tF3A57dpXIhOyyvnKXR2it5dR+i7YKkP+eckJQJgtL5M8Pyl e54xBBJpUyckg== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Anton Romanov , Paolo Bonzini , Sasha Levin , tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, kvm@vger.kernel.org Subject: [PATCH AUTOSEL 5.16 06/28] kvm: x86: Disable KVM_HC_CLOCK_PAIRING if tsc is in always catchup mode Date: Tue, 1 Mar 2022 15:13:11 -0500 Message-Id: <20220301201344.18191-6-sashal@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220301201344.18191-1-sashal@kernel.org> References: <20220301201344.18191-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Anton Romanov [ Upstream commit 3a55f729240a686aa8af00af436306c0cd532522 ] If vcpu has tsc_always_catchup set each request updates pvclock data. KVM_HC_CLOCK_PAIRING consumers such as ptp_kvm_x86 rely on tsc read on host's side and do hypercall inside pvclock_read_retry loop leading to infinite loop in such situation. v3: Removed warn Changed return code to KVM_EFAULT v2: Added warn Signed-off-by: Anton Romanov Message-Id: <20220216182653.506850-1-romanton@google.com> Signed-off-by: Paolo Bonzini Signed-off-by: Sasha Levin --- arch/x86/kvm/x86.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 0714fa0e7ede0..18fc0367ef21a 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -8769,6 +8769,13 @@ static int kvm_pv_clock_pairing(struct kvm_vcpu *vcpu, gpa_t paddr, if (clock_type != KVM_CLOCK_PAIRING_WALLCLOCK) return -KVM_EOPNOTSUPP; + /* + * When tsc is in permanent catchup mode guests won't be able to use + * pvclock_read_retry loop to get consistent view of pvclock + */ + if (vcpu->arch.tsc_always_catchup) + return -KVM_EOPNOTSUPP; + if (!kvm_get_walltime_and_clockread(&ts, &cycle)) return -KVM_EOPNOTSUPP; -- 2.34.1