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 36F94C433F5 for ; Tue, 10 May 2022 14:06:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343758AbiEJOKJ (ORCPT ); Tue, 10 May 2022 10:10:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51376 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244955AbiEJNrI (ORCPT ); Tue, 10 May 2022 09:47:08 -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 1640A35DE6; Tue, 10 May 2022 06:32:59 -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 2CB9FB81D24; Tue, 10 May 2022 13:32:58 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6F196C385C2; Tue, 10 May 2022 13:32:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1652189576; bh=68/j1f2siY5vbwja/tKj5PvdogndN7w1f7F6F5vMHDk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=J4ptrCC5dsXh/0GNvDpTS8GaYQFaX1KA1nOxFwu83tFNg5VjBdcYwiy3ke/Wabdmk EW701hRs8XZU/3qGXt1M9EV6Z9fNYncQ/PIavf4BbkPZlgSDUntFSQ5qHos7AxhIIS PqLFoqTyOMEDJrQmzJSu0AGeoxoXf0G+Kx1HsGKM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Marcelo Tosatti , Wanpeng Li , Paolo Bonzini , Sasha Levin Subject: [PATCH 5.15 096/135] x86/kvm: Preserve BSP MSR_KVM_POLL_CONTROL across suspend/resume Date: Tue, 10 May 2022 15:07:58 +0200 Message-Id: <20220510130743.163561108@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220510130740.392653815@linuxfoundation.org> References: <20220510130740.392653815@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: Wanpeng Li [ Upstream commit 0361bdfddca20c8855ea3bdbbbc9c999912b10ff ] MSR_KVM_POLL_CONTROL is cleared on reset, thus reverting guests to host-side polling after suspend/resume. Non-bootstrap CPUs are restored correctly by the haltpoll driver because they are hot-unplugged during suspend and hot-plugged during resume; however, the BSP is not hotpluggable and remains in host-sde polling mode after the guest resume. The makes the guest pay for the cost of vmexits every time the guest enters idle. Fix it by recording BSP's haltpoll state and resuming it during guest resume. Cc: Marcelo Tosatti Signed-off-by: Wanpeng Li Message-Id: <1650267752-46796-1-git-send-email-wanpengli@tencent.com> Signed-off-by: Paolo Bonzini Signed-off-by: Sasha Levin --- arch/x86/kernel/kvm.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c index bd7b65081eb0..d36b58e705b6 100644 --- a/arch/x86/kernel/kvm.c +++ b/arch/x86/kernel/kvm.c @@ -66,6 +66,7 @@ static DEFINE_PER_CPU_DECRYPTED(struct kvm_vcpu_pv_apf_data, apf_reason) __align DEFINE_PER_CPU_DECRYPTED(struct kvm_steal_time, steal_time) __aligned(64) __visible; static int has_steal_clock = 0; +static int has_guest_poll = 0; /* * No need for any "IO delay" on KVM */ @@ -650,14 +651,26 @@ static int kvm_cpu_down_prepare(unsigned int cpu) static int kvm_suspend(void) { + u64 val = 0; + kvm_guest_cpu_offline(false); +#ifdef CONFIG_ARCH_CPUIDLE_HALTPOLL + if (kvm_para_has_feature(KVM_FEATURE_POLL_CONTROL)) + rdmsrl(MSR_KVM_POLL_CONTROL, val); + has_guest_poll = !(val & 1); +#endif return 0; } static void kvm_resume(void) { kvm_cpu_online(raw_smp_processor_id()); + +#ifdef CONFIG_ARCH_CPUIDLE_HALTPOLL + if (kvm_para_has_feature(KVM_FEATURE_POLL_CONTROL) && has_guest_poll) + wrmsrl(MSR_KVM_POLL_CONTROL, 0); +#endif } static struct syscore_ops kvm_syscore_ops = { -- 2.35.1