From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pg1-f201.google.com (mail-pg1-f201.google.com [209.85.215.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6AD7742A793 for ; Wed, 1 Jul 2026 19:33:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782934402; cv=none; b=Rt8PLfkgJ567SvzG/M0hw+IvUrWg1AHT9YrNS4ehADK676CWHBt9vFIt7GK0OWNWCQDr5wVY4vOcC2/pr6erRfBoGRu72TFV93ReZ1b1UfHPWHgW4wDMgZDvQG7Ux7fX0MkPcfuOiYCc/iTLy8vyl9mKQq8CNOMprBFv464rdIM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782934402; c=relaxed/simple; bh=5RmHG8jQeFaxWLyXRFh1e6DyJpHBisQQEigG7SgzsNI=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=BS38Mkkl91aW8axrjwN5pTDybeehxMpsZQp8JGb+4zwpGmsZzrYrgP0agIDOPSe6Xw3vh5lFgyYo+g8tMP/IUDGiBYDUW+55UCLH3rzs87otlSjtt6aqXjZHEd7WzsNgc2NlVNUfLlhw9tK/u3sd55+oBHZwRAxg3Pq836Qw1fE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=SuVFKY6P; arc=none smtp.client-ip=209.85.215.201 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="SuVFKY6P" Received: by mail-pg1-f201.google.com with SMTP id 41be03b00d2f7-c88cfe287e1so886388a12.1 for ; Wed, 01 Jul 2026 12:33:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1782934400; x=1783539200; darn=vger.kernel.org; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:reply-to:from:to:cc:subject:date:message-id :reply-to:content-type; bh=VKCobU9qtcP/hN9BlhIiU1X9DFbnjtpoNJAd58RipCc=; b=SuVFKY6Pn8WHrrhDJo65fRVbP0QSq14/ulHcDZTceBBjSXQTUxS8cbOe8TRHeTQOXw n0BLMdtEUGhWNU/eUEEJCd+av1RT4Q1srto5DQmnWFa/xNMQ6xcCZ7t/Qg15KdEKo5ev Cb0Sonw9PqLyxUHyO8V6K1AKnmobUrvImEuf8Wy50/OlGHTeLpgB+l8Db1Kbj0FRZzPF IzVWTDiHYsgpZkUjRjc8i3ffd8sTdADTPIXkd8LYebsQfCZdXR4b3vJTRvB0Y/FLeIyD 0yFhZ/W51zyjkBzK4IK6OFG3GQ2KwrHlGOjzIGJHV/sX72s1MDyAusZMO4NEDptYOqSq FzNg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1782934400; x=1783539200; h=content-type: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:content-type; bh=VKCobU9qtcP/hN9BlhIiU1X9DFbnjtpoNJAd58RipCc=; b=r8PXOVk+olRYSZnw+dv/bppFSSkGGklYT98dUB4CIazcrx60k0oph5yt5z+m7gJPZ+ I/iVIdEWQeUONkyD4oB4JZX/q5sRI5caXKcbSOVax3O5Nm+SMeTMCFbCcQShjUfjY+tH S1RzyiApxcYwnRHQQkRD+XaTQm1MUoo6MhGsCPuPjJoWPnb7X9p4ZkXTsxw/aLopAeQ0 Wduvsb6hzHskxECUGjOKZpIn8t7ufl2BiN/L2p9+/yqr3IthHfuKOt3NXFem8funf+FV TXdcaYgZBS7OgpKAxt5KxAV2c7ph2Y67AZadTjW5D0oTfwg8xwQp89KD+moYlk0S10LA d9SQ== X-Forwarded-Encrypted: i=1; AHgh+RpGqF1L7m1erVkdNBQb1KAztfgcRz381aZRB46qFn77Dr4xvQpN505/wyfwraRG+vhD6OlJxC5kfM+M0L4=@vger.kernel.org X-Gm-Message-State: AOJu0YyZTanmQ0BeRb3FPA475NJMd5Q5y92AMSlbsMpCbuuisAonS1a/ HnEWyFNjkDIfl463PxOfeZUUyrCjY+dPymTyjARfQgvHcelRLxt1TiMU2PC4zWRNmFSXwWiqjA6 qwH8MeA== X-Received: from pjqu11.prod.google.com ([2002:a17:90a:ae8b:b0:37d:8595:7a08]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90b:180e:b0:37f:ff9d:ad69 with SMTP id 98e67ed59e1d1-380ba80c706mr2175388a91.7.1782934399271; Wed, 01 Jul 2026 12:33:19 -0700 (PDT) Reply-To: Sean Christopherson Date: Wed, 1 Jul 2026 12:32:04 -0700 In-Reply-To: <20260701193212.749551-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-hyperv@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260701193212.749551-1-seanjc@google.com> X-Mailer: git-send-email 2.55.0.rc0.799.gd6f94ed593-goog Message-ID: <20260701193212.749551-44-seanjc@google.com> Subject: [PATCH v5 43/51] x86/kvmclock: Hook clocksource.suspend/resume when kvmclock isn't sched_clock From: Sean Christopherson To: Jonathan Corbet , Paolo Bonzini , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, Kiryl Shutsemau , Rick Edgecombe , Sean Christopherson , "K. Y. Srinivasan" , Haiyang Zhang , Wei Liu , Dexuan Cui , Long Li , Ajay Kaher , Alexey Makhalov , Jan Kiszka , Andy Lutomirski , Peter Zijlstra , Juergen Gross , Daniel Lezcano , John Stultz Cc: Shuah Khan , "H. Peter Anvin" , Vitaly Kuznetsov , Broadcom internal kernel review list , Boris Ostrovsky , Stephen Boyd , linux-doc@vger.kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-coco@lists.linux.dev, linux-hyperv@vger.kernel.org, virtualization@lists.linux.dev, xen-devel@lists.xenproject.org, Tom Lendacky , Nikunj A Dadhania , David Woodhouse , David Woodhouse , Michael Kelley , Thomas Gleixner Content-Type: text/plain; charset="UTF-8" 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. Reviewed-by: David Woodhouse 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 61d4d943fe74..41aff709b90a 100644 --- a/arch/x86/kernel/kvmclock.c +++ b/arch/x86/kernel/kvmclock.c @@ -152,7 +152,17 @@ 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) @@ -223,6 +233,8 @@ 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) @@ -318,6 +330,15 @@ static __init void kvm_sched_clock_init(bool 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); -- 2.55.0.rc0.799.gd6f94ed593-goog