From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f202.google.com (mail-pf1-f202.google.com [209.85.210.202]) (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 16CBD3FF8A5 for ; Fri, 29 May 2026 15:08:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.202 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780067302; cv=none; b=upabWNR4STuQZBXkYgLSxSI9BeQz06oeEEo5p2CU/kcriR1fnUBAjXjPl4fmY+nuSAR2bSynPab29hW4h4B7czkG9gTNfgHQduLfoylpAyVEAUe6irLGl5AgcCmIY6vvSSAaysqP7vxiIn+RmRF2qDsrzFy1pyBXPzwoSw8azsQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780067302; c=relaxed/simple; bh=FXFmm/bt28qzsjhzY8TENCjzEiTjb//R/uZtmzqCTi4=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=pz/jag+KztiHaq7+UUSHi2ADNHjcFBSuHaas5sC/0EKpHVlnnwU020M2MjrJm6Fg/Baz8Ib72BxpR60IFhPhqOu1u7S7Q58DFmyRbgqCsenrjR2Nt5xsvMRb8eKAySwjrX0cSuab9sSCDsyfTefoyDD55AgRoSHvJlKM1n7a3P0= 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=YKnqxczI; arc=none smtp.client-ip=209.85.210.202 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="YKnqxczI" Received: by mail-pf1-f202.google.com with SMTP id d2e1a72fcca58-82fa2165c3eso9300766b3a.0 for ; Fri, 29 May 2026 08:08:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1780067300; x=1780672100; darn=vger.kernel.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=hiLxlYw3clwD2dLxI09vlAh7vN9DHw/HVEHbWWzJKBk=; b=YKnqxczI3yawyQxppQjpZXSdQey8KrFecNNN0NvjBTtgm0bcy3t+XH1QKRoKsRMtMk VyLieqz2PAHG55nVmLrlV6FfVLLshwR499Lc7dHchGVk5vIboZKP6qHuuO7sEFD4aiBR RCzta4gO3pwvos5mcUFstAR/sBhCVsP8qyDIddv4BHjfdaXglNYq8aufIk/P+T1S1HPA UUSgsfudVdVs3XHt2HaU0nn0aJyfuTgE8J1Z4Wv8woe/80qke/fQmlvWvnEIGyykZ/SQ 8wHYOruGsqFE90xIsKTv7MdB7Os1ItoGcE96asK5DBJ6t0b7Ac91cCZrOArYiALAp5B1 cyDg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1780067300; x=1780672100; 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=hiLxlYw3clwD2dLxI09vlAh7vN9DHw/HVEHbWWzJKBk=; b=YOIUpoY0/su3QnCmuXqg87Tv7kyZRq4vC0AU3wFGSZQe0X0Lg897RV/QOQH9FitxEx P1Y48fD5bzIyqSIzigK136YwdajLPx8NdIfW1S8YTNHiaWcqgFu5vsTmK+z5EXZKH1/9 ULVmxK/0IEn5Xfn8qhQuqjzIKWObvxAh/yW2hd98oavDfpD4ne5JyUMk0p0BsF9Jt53X TL51nZeOXvcfsCzNCAvqC0O9qaj3gg0ANe4uVWp/gtgSVmIIQkIR2yp34PtsK5ozhAe7 zIbCP4JlRmZM/jGKRKFmJYURMXoX+49rAlTLMzvMWYnn2OUAENAcxRVzS1qWcOueAOmP Y49w== X-Forwarded-Encrypted: i=1; AFNElJ8caSeaBrEhpuBlrHIHPG9fnuB0ysWTgZGeGjaWuMjIOBo1jypGiK3aiZfQ3fWLgZ3wPjeob0eer80QWew=@vger.kernel.org X-Gm-Message-State: AOJu0YwHcIZy80ubzIMkpWHXlyguYj/ywrMdR6i6C+QnCSujRml7xf/V df4pa2DvL2IQnWR028cVycZQleIUaNCJoQJ9FwcXZMCFEXO0oM9jZvs95V33aboLnHwdxykHhXs N9kOkSQ== X-Received: from pgx6.prod.google.com ([2002:a63:1746:0:b0:c79:81bb:79ef]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a20:9149:b0:3b2:a958:a725 with SMTP id adf61e73a8af0-3b411e478f7mr4139551637.41.1780067299927; Fri, 29 May 2026 08:08:19 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 29 May 2026 08:08:18 -0700 In-Reply-To: <20260529144435.704127-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260529144435.704127-1-seanjc@google.com> X-Mailer: git-send-email 2.54.0.823.g6e5bcc1fc9-goog Message-ID: <20260529150818.714760-1-seanjc@google.com> Subject: [PATCH v4 40/47] x86/kvmclock: Hook clocksource.suspend/resume when kvmclock isn't sched_clock From: Sean Christopherson To: Paolo Bonzini , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, Kiryl Shutsemau , 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: "H . Peter Anvin" , Rick Edgecombe , Vitaly Kuznetsov , Broadcom internal kernel review list , Boris Ostrovsky , Stephen Boyd , 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, David Woodhouse , Tom Lendacky , Nikunj A Dadhania , 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 4e304f1c887d..5dfac79a5d30 100644 --- a/arch/x86/kernel/kvmclock.c +++ b/arch/x86/kernel/kvmclock.c @@ -131,7 +131,17 @@ 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) @@ -296,6 +308,15 @@ 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); -- 2.54.0.823.g6e5bcc1fc9-goog