From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pj1-f70.google.com (mail-pj1-f70.google.com [209.85.216.70]) (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 AD9214A823F for ; Thu, 6 Aug 2026 23:37:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.70 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786059440; cv=none; b=U/Rx5Qu51zCv9mwxtuXCf0VOVpa51KderocS4HL38KuIIvhX4MHs4j3QwM8NyuIYf/jZmFxR3aWJr8ve1vGrnqVmbr1/Uf5WzS+3OUt4KXoszFT5gFRiaI0qDuwglNp8syqFRqKBTgeQBSbkNSLvG/lWFuiZRwFzjY0VcWpbeT8= 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=iuhPTXp1; arc=none smtp.client-ip=209.85.216.70 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="iuhPTXp1" Received: by mail-pj1-f70.google.com with SMTP id 98e67ed59e1d1-38e8e864ef0so3993327a91.0 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=lists.linux.dev; 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=iuhPTXp11FH8bhgCygErWvVegkGc1DyqqOgMdguS+aEKQV+bKTJZw/+3iknrPsgMn8 RMs2cRFmBJCJcncLdovKCQZV1E0tZX69YXpaaYmu2+mCgTQriKnUcQACxXFc1C7DEbHv SnvVL/y+Fh3BsiEZm+aosIcRI3q1gSUBAOTnHOmCM36qXxCSbYCx8X1bnMA01JdqjBbD Sp8SrUBvgtnqeZniKh2N9UzGMDHJGxJ2FCShgRun/eItYBg/NmcIFzjOHVSflCIfAqsf CSKIHGNQT4FAlHbyezXG1e7PwGZsGjHWNye+wT3BlM46fomflqbVjInfb8TK2AnzJHU7 x3oQ== 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=F4lJwVjLGQgEFxSnw1Vytw9nFAOBIxHeQMtAj10lTtoNY74GBTG4nhTcPAkZcgkqvq 1TZRoIsrlI+NdLh1ow5TDXJJGTDZp6/BLWbb5vi5RUQNoC/2wQhg418G+cfB6ylh5imt EicBPjunXczyqJSSqS9rdC1GaoR8AWAm+EQvcDjTTCVPY/vLB1dhrI4zmSWHfSCOp9PF peRHKtGF5iffHRgEdG+t6ClVYTNJAZfEdGvtTnMBm8Si/sz8Gt7d7aROl/4W5pNcZP4k ch0GkcMQ/8BYTUqhlxhG+Br8eVZq0dXqg54lQEEatUqcCKZhQO8qCezD6xQsKHntohE2 TAOA== X-Forwarded-Encrypted: i=1; AHgh+RoOzJdf6Y3AIauX7cHoR0MbByw5kofA0gpbyc1RVIAw6tsn7BZZxY2qIYzWBL0Khs1ZpJVZSoHOGGh8OfhY/A==@lists.linux.dev X-Gm-Message-State: AOJu0Yxtyz2QoKXbAHeRiQj2MYKsfi5Ei12/Z7zemwIgsiPEma1QRTyG PU3gjr2Hljoqi1Bjw6tmt5Zh4j0O/jOGktTYhsIqICy4du1g4w3hzmhbHAR+xA3CW3VaRYV7M0c MkpXlYw== 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: virtualization@lists.linux.dev 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