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 AD5303B6BFD for ; Fri, 15 May 2026 19:21:03 +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=1778872865; cv=none; b=Wg5M+rKKRHZUv7eQP34hAP/CYvbtFvDD26I5NFnjQ1OQV1EUQXEyemG8hFl8AUsBl86dFqPSu/VvUp6QVrKhPW+SqjV6xr3dpTW8xl5Zc0DQDFjS7EkNIetqLqW/AnmvvKD5B1+clHbfYSQtD+bURhHN/8Em6/D1D1oBIaKXOMY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778872865; c=relaxed/simple; bh=++iwLO4D9TJzPz8kuVQ32pM9hy17JXnAFhkjXdC7Tyo=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=B9gvNmr5SBn717e5mA9r1bYA7rxTHl0X1fVuNTYukhZCsGCNIWjiVFzY2maDYjZFHlsHDPcDP+elL5omRg+CISM8IGmuWyV0VXwmIo0JhQQdHoSBV+oxBfjrd9r3p/XnJ4xyZym9we3tszgc34zALpu60D9x9WjHmsCKO1Ghw8E= 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=WiNyH4Eg; 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="WiNyH4Eg" Received: by mail-pf1-f202.google.com with SMTP id d2e1a72fcca58-837d43e9ff3so95299b3a.2 for ; Fri, 15 May 2026 12:21:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1778872863; x=1779477663; 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=cmCCoVXH/wzfqmDby7kD+g/lqwg2CVoD5UqPiffRRm8=; b=WiNyH4EgkSkGLo5UY/FqEkQ+GcvsC5gGeLEmdJrO/wKCF5W5PcPAjrMdc8pF45dOVr duuJBVD0V2aQUAxk0daA+LrQqRAl9B0uTXEUJVjR1Cx/BOW8liKPJp69WzgtRY4pyCJf qtV3BqnoHfgD3p2YmO2Ly4QHSVxxd0+pWeMZvywm+r9qC+ZwsiSCWY0BKUCwazBw3ZEX pYOmIEzbP+IOaxSls4h6CprAkHZMdBpUg0pOMRqynVYIulTTtCRjqYp+scoVPK0Qv+3v QH9acRF0jGDE3kVCudHAAKRitwMROdkRMitHNu39QSCm8ULokSsxl5xRPQncWKA6Sd/N OzoQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1778872863; x=1779477663; 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=cmCCoVXH/wzfqmDby7kD+g/lqwg2CVoD5UqPiffRRm8=; b=sFpHNX6S5DvbvUtPRNKIuOcv6mlCpxIl5uigrdQyRUcdMI8MKfCq/bGzMc+fgU5xCP S7eLJLvzLvnhN+C26DVdm1hGx9oFbgvYPaVz8yw1MeQrmq2E4ZNDUwhIMvTwX9/n9tb2 zOnD9xEUA6UYnVJX8Eu9IXIXGZfMaOxAwBOcjgDdD6OJAHqSCTVCiabFDcvFpDHpYduC qDyiYynQ8CpZxdnP1xj8zvoehg5QCF0ca4XVT0y0EXLuIsK9K/Kxn51F2mI1BIrGXi7W VWS9nC+lDj36GxJzYoReRTJqF1fVuhvGt68C6LZWzvJpgsCpolCTcgp9cpUHX1SdWdeg SjGA== X-Forwarded-Encrypted: i=1; AFNElJ+wC+obKfB49snNECA04ZPOlytPX7KgPrZwnIEmO6IywvjE5bPXqAOOWatFrrA0gL/bAWXqRQLqx073y24=@vger.kernel.org X-Gm-Message-State: AOJu0Ywy9N7mBLN2V+F8CMsFAg4mCBEXneDqYuCCRK/kGtH227irx+J6 5/89t2AhfL6+UN3waza4iz4g4lIqlkftn8TzYQvyOkCRZXi7IkOVm+jqblWgFMxfBpTvu8zSA1o rFu7meA== X-Received: from pfbeq3.prod.google.com ([2002:a05:6a00:37c3:b0:82f:ad57:40bb]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a00:44c3:b0:82c:6da7:2d3d with SMTP id d2e1a72fcca58-83f33c2a8fdmr5145208b3a.11.1778872862416; Fri, 15 May 2026 12:21:02 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 15 May 2026 12:19:26 -0700 In-Reply-To: <20260515191942.1892718-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-hyperv@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260515191942.1892718-1-seanjc@google.com> X-Mailer: git-send-email 2.54.0.563.g4f69b47b94-goog Message-ID: <20260515191942.1892718-26-seanjc@google.com> Subject: [PATCH v3 25/41] x86/kvmclock: Hook clocksource.suspend/resume when kvmclock isn't sched_clock From: Sean Christopherson To: Kiryl Shutsemau , Paolo Bonzini , Sean Christopherson , "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: Rick Edgecombe , Vitaly Kuznetsov , Broadcom internal kernel review list , Boris Ostrovsky , Stephen Boyd , 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 , Thomas Gleixner , David Woodhouse 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. 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 ccb2aff89b2f..655037949446 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) @@ -202,6 +212,8 @@ 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) @@ -297,6 +309,15 @@ 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); -- 2.54.0.563.g4f69b47b94-goog