From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pg1-f202.google.com (mail-pg1-f202.google.com [209.85.215.202]) (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 28E7A423F7F for ; Wed, 1 Jul 2026 19:33:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.202 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782934393; cv=none; b=TFUENQKyUorE0EZLFqn0ijWLhuVQejMzRTP15CH+BBS78Ch9BXAEyBLYef0arC49I588CFfmH5/0qUECwvJJ3MBzb3Z0SAaTKf9SqXXXFMz7UDuh//8wWgY1pzgnQYLfYnHmiZucwHNf6WPSvoE2qoqVeBphDrKiVqSsCT8iEiU= 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=TNLNEavc; arc=none smtp.client-ip=209.85.215.202 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="TNLNEavc" Received: by mail-pg1-f202.google.com with SMTP id 41be03b00d2f7-c85798977dcso830458a12.0 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=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=bEdSCU5mjiDv3GADlP0fC3hWLpC5/Jr71iPsXhxCK9Y=; b=TNLNEavciSrrUvZpoTM3W3Xb0RDLWyv/8ewNn8byAPOaEHHw2WaU70Q0z9xyY5PmaW 27umSlY43bDyC8x8lW3ygoS/ZCzl0L83R3lC2fpAyfL0xn2ahN+8a+p/Pq9aSd124IK8 SNZv0DxqUsIyQ3Roai1h8TL18DaxghXeMXXkjDDzis+N3Xj3yCpcptfRdAGcl9le0gPx pXC3iO2/JNZs7L4UAU4/5dx0qP+Ipo8nQn7pPEwpGH4MBgwBc4OHzz0Zmg/MQPuK8zrL HwacizZEMo2YOq49VtLywnYMThkj71U+QXSGYlCNNuO31CaXiMVw0PICwR/lThbEgRQ/ fpDQ== 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=l2ENRmFNx1NOhdbgDhvqNrGaTcE9C9PlBabzAOSyV+pZHfvYebQnuT+7MrxQOrD3b0 RLQUcHPM6Y10wFdkW+mC//KMqe2ldA6ix5BKMl6rb1pBD/66vBvbVKdxXGyplQVflY96 yOkTN1+JJ4Pf6IUo5zr4/Ut15784HGlQnpUoFhao/wBxlmUQKv50/QGmGUlONlYkVn+H rM99YeMjPoW6H1sYW9cG9G7y50VkhTsz29RFyiDhJrxzCL2fYhoIA3p96idr4t+MeBi7 Uc7SDHwTd3iHy5GIqObvVRGlxbMQsw0gXgrv3PW8Qa5AZMeZGa8amWyS0okNlDR5S9ac rkuw== X-Forwarded-Encrypted: i=1; AFNElJ/V4nADG3PtUYgNMJ/Lqm6OBgWElVZt6M2Nd462hIResbCTlz/7iGfve2XwNKmfRpuOruZQB//dlYtvAkY=@vger.kernel.org X-Gm-Message-State: AOJu0YyYc6B9CYbrT1ZcIOOmWvCUKppooY6emrNCUBkduoOdEfjey+So Y82+zysWZ6SxKFEYjHSUk/qHEI2aHlRqB4Ylb81rqw7YX5I6HGKIORLKXGxZuCp2LuBXvw5ZyOB Khqgp0w== 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-hyperv@vger.kernel.org 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