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[23.128.96.18]) by mx.google.com with ESMTP id g23si574146jad.40.2021.09.13.07.21.02; Mon, 13 Sep 2021 07:21:15 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@linuxfoundation.org header.s=korg header.b=usguDJQN; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linuxfoundation.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345987AbhIMOUd (ORCPT + 99 others); Mon, 13 Sep 2021 10:20:33 -0400 Received: from mail.kernel.org ([198.145.29.99]:37130 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244927AbhIMOPN (ORCPT ); Mon, 13 Sep 2021 10:15:13 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 1954561AFB; Mon, 13 Sep 2021 13:44:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1631540654; bh=DI7UZ9nXG7PUChrM01ou+/ClgMigNDLbH4SHbiJzFKM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=usguDJQNAOBueLdhYzoJSl7XnpJPd8H7ImhSD9uQPRkRqJwSux/V245ekTi4grtjR RpDnnc9ARcH2yFEfyxDK/RN4jRq6CJfsknXcKR7YQ0SANfSop+4YSuO8LgqbcqRoCM UJtihqxDh7a3lRhAXGGrt2xRY0hispAiYsBkCA8k= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Zelin Deng , Paolo Bonzini Subject: [PATCH 5.13 282/300] KVM: x86: Update vCPUs hv_clock before back to guest when tsc_offset is adjusted Date: Mon, 13 Sep 2021 15:15:43 +0200 Message-Id: <20210913131118.869794357@linuxfoundation.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20210913131109.253835823@linuxfoundation.org> References: <20210913131109.253835823@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: linux-kernel@vger.kernel.org From: Zelin Deng commit d9130a2dfdd4b21736c91b818f87dbc0ccd1e757 upstream. When MSR_IA32_TSC_ADJUST is written by guest due to TSC ADJUST feature especially there's a big tsc warp (like a new vCPU is hot-added into VM which has been up for a long time), tsc_offset is added by a large value then go back to guest. This causes system time jump as tsc_timestamp is not adjusted in the meantime and pvclock monotonic character. To fix this, just notify kvm to update vCPU's guest time before back to guest. Cc: stable@vger.kernel.org Signed-off-by: Zelin Deng Signed-off-by: Paolo Bonzini Message-Id: <1619576521-81399-2-git-send-email-zelin.deng@linux.alibaba.com> Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman --- arch/x86/kvm/x86.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3223,6 +3223,10 @@ int kvm_set_msr_common(struct kvm_vcpu * if (!msr_info->host_initiated) { s64 adj = data - vcpu->arch.ia32_tsc_adjust_msr; adjust_tsc_offset_guest(vcpu, adj); + /* Before back to guest, tsc_timestamp must be adjusted + * as well, otherwise guest's percpu pvclock time could jump. + */ + kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu); } vcpu->arch.ia32_tsc_adjust_msr = data; }