From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pj1-f71.google.com (mail-pj1-f71.google.com [209.85.216.71]) (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 06F48448390 for ; Thu, 6 Aug 2026 23:37:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.71 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786059431; cv=none; b=DwyWdTtrFAVNM0Tkx+AHahJ8FFxcqFB+lFZED5vdqfJCmwpz46BgXR6gF1QPF2ByVIXsLv1BleEFyJUZ5t/F3akW4F9VGw7yf/IjUwWjvoC+82n6QhcXCBk80/bazkxiSrFss47XoviPb4gpL1x8xhBqwJHuVmhI+Er4sZOhKpo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786059431; c=relaxed/simple; bh=sbzLks0rCz/Y4FC4JU4m7+dMymRO89Rs74fjqXQ5fdM=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=XbM4xLXh7jrLSChuvrwTMFw/b+zTfQQmFIsWPcxqXze/tlL1h0tGHafIigeqDfg7ggyusoFAHdTFIKMtD2lk71Syqe2gSJZMubZElG1lFfS3DDPfxZ8rU0wDbtolBKs7p8Z0MdGH5GQt3nNn1erxo3LjFHd6uc89MeTchqh3JlI= 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=OZTMtvb9; arc=none smtp.client-ip=209.85.216.71 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="OZTMtvb9" Received: by mail-pj1-f71.google.com with SMTP id 98e67ed59e1d1-38dbf293831so5541546a91.3 for ; Thu, 06 Aug 2026 16:37:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1786059428; x=1786664228; 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=aQ8musMrPFB3W7GZXrEzufcFO/9G0XUPjz13+bRyF/M=; b=OZTMtvb9Amnluk+YAniV4gROWh2g07dD5BZioi8CRFJC7KeD/XqvnObIGhZDpywJjS R6pU1FVwihAytqpLlXvhdHIy8Y10gZSgxR2UdNIVsmCSVfivt9MwPUen5GZH4v0PzuCH imJF8VgqbhkLmsnA3F/LNgmsz6UsePbQmabJHVW7ty+e5SX9zMEMWB2Wih+dDQzrBAk4 e0G5Vt3s4Esk2pU2G2JJqskmmhYpbQJqyH6Swl5l4HLCBan1jTFOsVTCkpKG0/UDr5XG FaxVeXDv6tfBp5pD9HA+GnvHIrlWlIAOr6j6OQBVDa174SXgpuAyQ0iJx95pntlMyVDG Kjxw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1786059428; x=1786664228; 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=aQ8musMrPFB3W7GZXrEzufcFO/9G0XUPjz13+bRyF/M=; b=iZVbd2ROiC3uXAhwSebX2lKPhicwk/aTf+PNXmdqKdvM0RKf2NRM5p8JyGAuU+5mAX CP05/8/Y8qaf73WmbeJ76YwqKfCQQhOVHkZAC+i7WfjLTQzbIYbGZYJElSrjZwCGJzJL d5tpuvbzvM8AEwV1ImJOOHyCtQUANpjvsB/mstGXf/ivt3F94ca8mPYwTYkVWU4qkaAQ 6LYiYnZinkcXv+D0yPqUL4xdjWeEQYzxnFlafHKgTviNE34q4k/NML+5rup7+SHEi+/G 5gYRx2MOkwOjjjOhw8h+60KrBIeulm490bHpPh7qiC5ER8uiYhUwc8Qd21RhSOntCOIZ qgmw== X-Forwarded-Encrypted: i=1; AHgh+RopQ4PWhgPm8j6ODzqvnIyTTzYAqmLoH6AgoGzutSSZpZ4cfGSMXe6rU/kqk0ucRPBIAp9YuxKcsl1vFtgSDg==@lists.linux.dev X-Gm-Message-State: AOJu0YyoBt5wozCs36sSb4enOl4Rh7xOtx8kGE40egoMpEJO7h9QxdV0 KTLtqCt0HRh4rL7Nw3Nt3CGb77li7L4aaOdGbNJEUP4aPC3Pr3YICkIftXdNGaV/5fzaK8ZLFVn NtysGeQ== X-Received: from pjpq20.prod.google.com ([2002:a17:90a:a014:b0:38e:befb:90c6]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90b:264b:b0:38a:c3f:3b87 with SMTP id 98e67ed59e1d1-3903c58a6femr19988163a91.12.1786059428057; Thu, 06 Aug 2026 16:37:08 -0700 (PDT) Reply-To: Sean Christopherson Date: Thu, 6 Aug 2026 16:35:52 -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: <20260806233609.212337-36-seanjc@google.com> Subject: [PATCH v6 35/51] x86/tsc: WARN if TSC sched_clock save/restore used with PV 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" Now that all PV clocksources override the sched_clock save/restore hooks when overriding sched_clock, WARN if the "default" TSC hooks are invoked when using a PV sched_clock, e.g. to guard against regressions. Reviewed-by: David Woodhouse Signed-off-by: Sean Christopherson --- arch/x86/kernel/tsc.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c index 964f3d6c2c71..60fcc3020792 100644 --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -947,9 +947,17 @@ EXPORT_SYMBOL_FOR_MODULES(recalibrate_cpu_khz, "p4-clockmod,powernow-k7"); static unsigned long long cyc2ns_suspend; +static __always_inline bool tsc_is_save_restore_needed(void) +{ + if (WARN_ON_ONCE(!using_native_sched_clock())) + return false; + + return static_branch_likely(&__use_tsc) || sched_clock_stable(); +} + void tsc_save_sched_clock_state(void) { - if (!static_branch_likely(&__use_tsc) && !sched_clock_stable()) + if (!tsc_is_save_restore_needed()) return; cyc2ns_suspend = sched_clock(); @@ -969,7 +977,7 @@ void tsc_restore_sched_clock_state(void) unsigned long flags; int cpu; - if (!static_branch_likely(&__use_tsc) && !sched_clock_stable()) + if (!tsc_is_save_restore_needed()) return; local_irq_save(flags); -- 2.55.0.679.g6767b8d81c-goog