From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f202.google.com (mail-pl1-f202.google.com [209.85.214.202]) (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 1AC19423F7B for ; Wed, 1 Jul 2026 19:33:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.202 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782934393; cv=none; b=Sl4ugEyTo+O1T0DTS0N02INbP38q/zvG+9QPx/hjjRX6CwTpfbb56cj8sspnmNIlGjQ+bji5+CyZR/0duhWfYaY9fesGOFB7XQLHi8i0OzRZONz30ZNnTx+UuGEJZvSzF6ywQiIRHUeqJLMu7B8yd+32DQ8Ez3H7OXsSLCSTY1o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782934393; c=relaxed/simple; bh=CMkMn9gDHGDnd3gtJyIeM0lkE5As7w47pJpKewsK9/4=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=Qc4DGe2h+atTVvaG0qboHdHArCFIOpOuRtcqWFsZvLsEKw7C/jSyZTvfa35956VYAwcToz+rHavngFcuew9sk8NiNh1DCSe0AnX+Q3hyVnIhQd65zRtyRbcUXy39gLXMPnpvfkW+DKCNos1Av5jSg+CogTQo5Ofy0+cOSMeIm4c= 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=XObTsx6V; arc=none smtp.client-ip=209.85.214.202 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="XObTsx6V" Received: by mail-pl1-f202.google.com with SMTP id d9443c01a7336-2ca1f16e391so11752145ad.2 for ; Wed, 01 Jul 2026 12:33:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1782934390; x=1783539190; darn=lists.linux.dev; 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=bEdSCU5mjiDv3GADlP0fC3hWLpC5/Jr71iPsXhxCK9Y=; b=XObTsx6V9Vz6LvScSHHHpSGCvxCUnhsm+6AxdaD6iWPAoI5s14ay4TsXozwZHiQnbr opxZ/Zj83wWyU8Q3WfCM0V+AQdvlr+byS7hPvmbAIMXCWC6+OGR8emUwuAzLQlbUe8sI X39qdjvQkUIIwx6o1r7Rt1QuIzcntyTInjBX5KVDnQ1KMJJex3kRthEoB8+kvmSjZZpJ muOQUqFvinDYmisSyoXWQvTL/ckBE3kMjd8MyY7FRdyhVtltmVuYa0IkeU1p1PL7T3sd id2ZPFZ0bEgdQ3QqE4pRwe1kUTUQABeLY3t04aEYnoI8iHmbAmeLOm/2U2lqPoqUJDzm LY4g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1782934390; x=1783539190; 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=bEdSCU5mjiDv3GADlP0fC3hWLpC5/Jr71iPsXhxCK9Y=; b=JxC06qdJav42PowA5G2Ch8y2NeBlOXXe5vTICn63fGheh0KCOyPqnoRlPOjToVWkuM rioQ0HeSmMTTavETYJ4VYfVR+DSGB/PX96xHoBUeoB+MPbczNcErcKV+C3w+6wD+TxFO NmnEWqSYIFsubfi9hEuHHuCX+cD9Fg+xNCG/BvOfyqTrdFI2jFJltLxSYfjPt7pmuh8i qS2aB9eQdvOswbcxaIsoEPPxypCBnMuyO19SWmfNmO2MaKGLO5OOOJGDufJDkpAns2JC Wce3he80WWfM4wti3XBCBVRHKz4vDZpQAFNxbOC4qEJJIJWX5QTZrQt1ljGd9ZtsY9HZ mTfQ== X-Forwarded-Encrypted: i=1; AFNElJ8XXbdC+2Lx9YXNelP3UuKZL+st0CBdaF3qBHtDlhj6zIbBbXS/rbZh77tSGE8s0gcvTfNfJdc+aiF1@lists.linux.dev X-Gm-Message-State: AOJu0YxYmco9Xd6JCa5ijmc/v1l4BODfzKXVeLAR0O9O/wG06DWgVPE/ BS5eigTtSfj7H5ePHjrgTa5Y8CehaY3B1G/Mg/jvws4rc6iOI7lUMmPZNP9AUotUgS4EHAYnStd rnlSpIA== X-Received: from pgh6.prod.google.com ([2002:a05:6a02:4e06:b0:c8b:19f4:6228]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a20:4320:b0:3bf:6c08:fb88 with SMTP id adf61e73a8af0-3bfed4b9441mr3531733637.56.1782934389876; Wed, 01 Jul 2026 12:33:09 -0700 (PDT) Reply-To: Sean Christopherson Date: Wed, 1 Jul 2026 12:31:56 -0700 In-Reply-To: <20260701193212.749551-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260701193212.749551-1-seanjc@google.com> X-Mailer: git-send-email 2.55.0.rc0.799.gd6f94ed593-goog Message-ID: <20260701193212.749551-36-seanjc@google.com> Subject: [PATCH v5 35/51] x86/tsc: WARN if TSC sched_clock save/restore used with PV sched_clock From: Sean Christopherson To: Jonathan Corbet , Paolo Bonzini , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, Kiryl Shutsemau , Rick Edgecombe , 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: Shuah Khan , "H. Peter Anvin" , Vitaly Kuznetsov , Broadcom internal kernel review list , Boris Ostrovsky , Stephen Boyd , linux-doc@vger.kernel.org, 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, Tom Lendacky , Nikunj A Dadhania , David Woodhouse , David Woodhouse , Michael Kelley , 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 a762cb5cec0f..7473dcab4775 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.rc0.799.gd6f94ed593-goog