From patchwork Thu Feb 27 02:18:41 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 13993625 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 lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id ECF65C19F32 for ; Thu, 27 Feb 2025 02:26:58 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.897627.1306386 (Exim 4.92) (envelope-from ) id 1tnTbw-0000Y4-Ab; Thu, 27 Feb 2025 02:26:52 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 897627.1306386; Thu, 27 Feb 2025 02:26:52 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1tnTbw-0000XU-20; Thu, 27 Feb 2025 02:26:52 +0000 Received: by outflank-mailman (input) for mailman id 897627; Thu, 27 Feb 2025 02:26:50 +0000 Received: from se1-gles-sth1-in.inumbo.com ([159.253.27.254] helo=se1-gles-sth1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1tnTVA-0005qU-GQ for xen-devel@lists.xenproject.org; Thu, 27 Feb 2025 02:19:52 +0000 Received: from mail-pl1-x64a.google.com (mail-pl1-x64a.google.com [2607:f8b0:4864:20::64a]) by se1-gles-sth1.inumbo.com (Halon) with ESMTPS id 5096aaac-f4b1-11ef-9aaf-95dc52dad729; Thu, 27 Feb 2025 03:19:47 +0100 (CET) Received: by mail-pl1-x64a.google.com with SMTP id d9443c01a7336-22107b29ac3so7797435ad.1 for ; Wed, 26 Feb 2025 18:19:47 -0800 (PST) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 5096aaac-f4b1-11ef-9aaf-95dc52dad729 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1740622786; x=1741227586; darn=lists.xenproject.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:from:to:cc:subject:date:message-id:reply-to; bh=3WIlT5dxc8eqreSuMAUxshuXGBEM8C/NLPwcD1zy3Y0=; b=4Tn+HIhTEofezILu9LoLr1+pu4sBPUvjgk3YbPzy3M0AXjaXsUbZc4f6OR46LFkdHd xciMaZqRjYs9i8IlJcCFsXIKUhq357GYjhw/8k2kwgHHXHLhdRLEjrmJXqkb/BAm4Blo nlMlJftWNE+2aydySXvYI1v8NY0/b3vk0j4P+EreGa30VYXHy41E4Tpxsxj9qASbqZrF pz6zd1luV3gjXWWMi8+kLvZxHZuWuEHmd05S62mi1r17x9bOlsRtSLOTNUl30lUmHV1L Dgqulh3zfVGUM0FQ4UTFDhyfKqhNwiqDSlw0+OslEpFXCdDVslX3qA8EppCYsSoGhrc9 PfoA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1740622786; x=1741227586; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=3WIlT5dxc8eqreSuMAUxshuXGBEM8C/NLPwcD1zy3Y0=; b=pBfn8g52sZb2u7+SrPjtdiu2x28t9qsilOhu9eXbSR3C4gfmpgQ3Mi+vQMJmJV++1R PrN3KqdEfUdFL98LsA5iMLWcC/V5ykzjyp6Vzi87aR9Q2DNg8BnxAnr42G+4yOW0XHgM /UuL7rdOhm5QsMPT0JM4/LgdoT0dwK+5Fm+kKQusFsK+pcGyhZ59hLgWXTfNUhe2iWZj pYoeKeEPzypdUofgR3Jm22Lhk28etdcwJSjjw/qGtPpT5QQsHu/+0skrhuTpYweDa9kp 2JFyVCo3cHr4jh0CfyADMbGttjPnMoCyrS9VeNdl/5Tl3xJJ4xPGTwJL3iS84Hc/5eBd j1Eg== X-Forwarded-Encrypted: i=1; AJvYcCX/5Q0fgb7TMow7A6XNTNRB0mGDgxw0JCUtdWLrETFN/QOzUOW4TzC1BsBUgfIpIxCZQwKZ1dH45Iw=@lists.xenproject.org X-Gm-Message-State: AOJu0YxTC2fNGBINAsPX2TBLLe3WxWgTTA7zrgV5m5+TcLSCr3rg6DU8 z575FgCnVes/xzDGGsyR3OlNEQTKMTvfh3LIFt5TAp1rgsssv7yvvxXgQ+rGs/tqcW74z2Npb4h aqw== X-Google-Smtp-Source: AGHT+IEKa+U3XmhHVLGnMc9mY3OxJMjJ1pR3+E2erpOOt4xnyyZwND9G3ZoTVgYNZ7eny0ZZLwJ5fe0HKa8= X-Received: from pjvf4.prod.google.com ([2002:a17:90a:da84:b0:2ea:3a1b:f493]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:902:e80e:b0:21f:3d0d:2408 with SMTP id d9443c01a7336-2234a28af91mr27386885ad.10.1740622786458; Wed, 26 Feb 2025 18:19:46 -0800 (PST) Reply-To: Sean Christopherson Date: Wed, 26 Feb 2025 18:18:41 -0800 In-Reply-To: <20250227021855.3257188-1-seanjc@google.com> Mime-Version: 1.0 References: <20250227021855.3257188-1-seanjc@google.com> X-Mailer: git-send-email 2.48.1.711.g2feabab25a-goog Message-ID: <20250227021855.3257188-26-seanjc@google.com> Subject: [PATCH v2 25/38] x86/kvmclock: Hook clocksource.suspend/resume when kvmclock isn't sched_clock From: Sean Christopherson To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "Kirill A. Shutemov" , Paolo Bonzini , Sean Christopherson , Juergen Gross , "K. Y. Srinivasan" , Haiyang Zhang , Wei Liu , Dexuan Cui , Ajay Kaher , Jan Kiszka , Andy Lutomirski , Peter Zijlstra , Daniel Lezcano , John Stultz Cc: linux-kernel@vger.kernel.org, linux-coco@lists.linux.dev, kvm@vger.kernel.org, virtualization@lists.linux.dev, linux-hyperv@vger.kernel.org, xen-devel@lists.xenproject.org, Tom Lendacky , Nikunj A Dadhania Save/restore kvmclock across suspend/resume via clocksource hooks when kvmclock isn't being used for sched_clock. This will allow using kvmclock as a clocksource (or for wallclock!) without also using it for sched_clock. Signed-off-by: Sean Christopherson --- arch/x86/kernel/kvmclock.c | 23 ++++++++++++++++++++++- 1 file changed, 22 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c index 0580fe1aefa0..319f8b2d0702 100644 --- a/arch/x86/kernel/kvmclock.c +++ b/arch/x86/kernel/kvmclock.c @@ -130,7 +130,17 @@ static void kvm_setup_secondary_clock(void) static void kvm_restore_sched_clock_state(void) { - kvm_register_clock("primary cpu clock, resume"); + kvm_register_clock("primary cpu, sched_clock resume"); +} + +static void kvmclock_suspend(struct clocksource *cs) +{ + kvmclock_disable(); +} + +static void kvmclock_resume(struct clocksource *cs) +{ + kvm_register_clock("primary cpu, clocksource resume"); } void kvmclock_cpu_action(enum kvm_guest_cpu_action action) @@ -201,6 +211,8 @@ static struct clocksource kvm_clock = { .flags = CLOCK_SOURCE_IS_CONTINUOUS, .id = CSID_X86_KVM_CLK, .enable = kvm_cs_enable, + .suspend = kvmclock_suspend, + .resume = kvmclock_resume, }; static void __init kvmclock_init_mem(void) @@ -295,6 +307,15 @@ static void __init kvm_sched_clock_init(bool stable) __paravirt_set_sched_clock(kvm_sched_clock_read, stable, kvm_save_sched_clock_state, kvm_restore_sched_clock_state); + /* + * The BSP's clock is managed via dedicated sched_clock save/restore + * hooks when kvmclock is used as sched_clock, as sched_clock needs to + * be kept alive until the very end of suspend entry, and restored as + * quickly as possible after resume. + */ + kvm_clock.suspend = NULL; + kvm_clock.resume = NULL; + pr_info("kvm-clock: using sched offset of %llu cycles", kvm_sched_clock_offset);