From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f198.google.com (mail-pl1-f198.google.com [209.85.214.198]) (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 844314AACB3 for ; Thu, 6 Aug 2026 23:37:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.198 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786059440; cv=none; b=C5QO5j8orE982en4rAAELtv//h1iGintvr1Tg+wE6z4Xrey9bqzNckvfQ750mULrsjAr7icDkfARpTMz/YDG9mbzUNnDgemunVrn8MdNuZu0npsPNzPnLosUfj8Scj+s5mm3eDEf+irBSbdvPk3MKEgrmYEn8pzD6xWuS/w0+L0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786059440; c=relaxed/simple; bh=K/EtG7hsgatUBHi5bWDjfRauVW7X2RN7VoYeeZHucVI=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=lO1PXNjkzwRgeSIQ8CzaeBAXljmHx4XjLWMW7AbptRtHl3y0iRldohEPlKqL/3HhYQTiNzeCekpJ5rHI5NsHNLcxzc5A6+EPJgCGyq19VHOOzbp4WRw72ek5sqEJzWeMD9ssNIH7Erv6epuJ4sywEiJQhmSOOZgH7X8bfX3B09o= 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=YTh/0ag6; arc=none smtp.client-ip=209.85.214.198 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="YTh/0ag6" Received: by mail-pl1-f198.google.com with SMTP id d9443c01a7336-2ce7dfd33ffso32943215ad.0 for ; Thu, 06 Aug 2026 16:37:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1786059438; x=1786664238; 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=LM+bFo6oZyT6hMjeOJv5/5C5Sfvue9FfV0H+MNWzQd0=; b=YTh/0ag6tM/oAFVXEVZwkvasp1gMe3Oe67/vLfSgvsTOCg/wOEI/b8fhPZSfZwz0g5 cB1R9kASN95ueg2IRg+EFjQ+ws78kzDFL4nW9h5NzSf2EZygNy6TmX2rTXTnblQzXe8a agwvYeyoeay4CQiIG2SCt5FtWzNe1ZbtRbvGp+43tymkXV3cjTtEj6LBmkbEddrpaqeF ZCAbOAGdbNFRCy1E3T8WkOfz0c5CIjVjBcK0Iao/hH+Gs3DHQ0Jo0e7e2IUbLTbVCeWE 9r/urfp0duXhRQ3CBXysgQ3x5H2zszueT3tx910uI6N7/U5OOLGYvP7bIihxPvOqUH/l vLKg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1786059438; x=1786664238; 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=LM+bFo6oZyT6hMjeOJv5/5C5Sfvue9FfV0H+MNWzQd0=; b=IvkI+viWxSXk4Fntl7Sdid2xpClW+7/VssLaX008xfdbvLTLBcOizlsyRyQlUXjZ06 6z3a5fY4nBDql+pgTCH60qIgw/IuUCVwDIga3yJeQT+rfyqj6ucnmvNSCI+F1+FLYWyP yzR3lNOEyTddvGuMCC6vj51/Fvm8NGXnymcbBzBAsIh5d+ZCRCYTCTx4NAWADBhjEGhk dNZARzdBDDVqYanhFWwnKyGP6zpv3A0yJ2dM5JRa6ZJX3gtmgukWB43EOoIdN6Jql5X8 WdMMpp5lOTvZMjrBQFAn1dQEaZbPmq2Ivh50i+oJoB01oBFT2MpicptCg7FMvqYMrU/S 5kZQ== X-Forwarded-Encrypted: i=1; AHgh+RpyNJCTtst4HW7Zv86TDuspRLBn43UyY09esKpXzFHPNsKDeumxatL4+4k22RO4KC5icp+JLaCyvJ5BPm4=@vger.kernel.org X-Gm-Message-State: AOJu0Yxjpsm6H0fhARZMLG0jBiFIAMQZzuFH6Xivm8xXfZOm1IFFz5Jj kJyURPnqMCkXld9SF9pYIyt3zEOSlrOkEBtFBAwu2b0kBwTqeAypaBftrFTdBDKX9kQWSjtr+Mo OxnH8BA== X-Received: from pjuf1.prod.google.com ([2002:a17:90a:ce01:b0:38e:aa86:7cac]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90b:5447:b0:380:83fc:4315 with SMTP id 98e67ed59e1d1-3903c66b3bfmr20385633a91.21.1786059437671; Thu, 06 Aug 2026 16:37:17 -0700 (PDT) Reply-To: Sean Christopherson Date: Thu, 6 Aug 2026 16:36:00 -0700 In-Reply-To: <20260806233609.212337-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260806233609.212337-1-seanjc@google.com> X-Mailer: git-send-email 2.55.0.679.g6767b8d81c-goog Message-ID: <20260806233609.212337-44-seanjc@google.com> Subject: [PATCH v6 43/51] x86/kvmclock: Hook clocksource.suspend/resume when kvmclock isn't sched_clock From: Sean Christopherson To: Kiryl Shutsemau , Rick Edgecombe , Sean Christopherson , Paolo Bonzini , "K. Y. Srinivasan" , Haiyang Zhang , Wei Liu , Dexuan Cui , Long Li , Ajay Kaher , Alexey Makhalov , Jan Kiszka , Dave Hansen , Andy Lutomirski , Peter Zijlstra , Juergen Gross , Daniel Lezcano , Thomas Gleixner , John Stultz Cc: Vitaly Kuznetsov , Broadcom internal kernel review list , Boris Ostrovsky , Stephen Boyd , Miroslav Lichvar , x86@kernel.org, linux-coco@lists.linux.dev, kvm@vger.kernel.org, linux-hyperv@vger.kernel.org, virtualization@lists.linux.dev, linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org, Michael Kelley , Tom Lendacky , Nikunj A Dadhania , David Woodhouse , David Woodhouse , 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); -- 2.55.0.679.g6767b8d81c-goog