From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7F66B1C75E4; Wed, 20 Nov 2024 14:59:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.92.199 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732114750; cv=none; b=GQrwG1rtKtaU8zoIVYpr7kRpp3H3M1gGh79MRZlsysnfew6OmFG5hb6j3MR1xdrZwfit+GoTczjU9s8qowCuiLCig2QO2i1BrUZtuaD6B+otOx45W4xgLKzLUtNQ9gu4XAbiVcLAraxP5Fl7Cvjc04s8ojVyj0zVxe54mtXF6FA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732114750; c=relaxed/simple; bh=mgj4bvZ/X9lF9Afs6hkeLwqdCb98lX1871WUaw0D2YA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=lR9z8/eFuwg1UW2ePQRwhG0ltELJBe8h+TRmGaRTlARm5oVwT7vZT2ehMRj9Il+mwlkke8UP42tBVAMjqKe4wP7s1GhKdE3pxEtv9DXDbzbY0qpISnA8Cc7EtzfrtKw3h+G0wwD4VUsZwiJ+qsXsmt3VhJDKrIS0KJUUvAGz/ls= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=ew7HvsRk; arc=none smtp.client-ip=90.155.92.199 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="ew7HvsRk" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=RkowXip/85xKsOA9eS4V3TnfVFLeWlFM6e9qis0TUFo=; b=ew7HvsRkHFTom5sTnUqzSG0oAO ph2CPqO/ygxJ/UPM1WUb+pYR0aHrsOxLuya8BpPk6cbQe7m4o8R6UyxrT56fisaJpI/vFiYU6Bxds 9kG361m6Pt6bVUEHKciM9MNv6n0DeDnr3UoPQ1HATq0bL/rvVgpKHO/CPebxjZHz2SGumyNYakGU8 gLKwJSCZ55FiCvjyNICyvPDS/wqrke6fPTkuii22vWFlAQRkd2AK+ZRfhifvacNWLsUjG2bXsE/p7 Wwtsy0LReGjbKYrASQ0vbBFba1zyTDzJKYiUZiSs1m4+1RHu4gw19DuBmdh21X/FztxkFnivc9Z6I zfyYJrNA==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.98 #2 (Red Hat Linux)) id 1tDmAb-00000000TrW-1QgA; Wed, 20 Nov 2024 14:59:05 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 025EF3006AB; Wed, 20 Nov 2024 15:59:05 +0100 (CET) Date: Wed, 20 Nov 2024 15:59:04 +0100 From: Peter Zijlstra To: Valentin Schneider Cc: linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, kvm@vger.kernel.org, linux-mm@kvack.org, bpf@vger.kernel.org, x86@kernel.org, rcu@vger.kernel.org, linux-kselftest@vger.kernel.org, Steven Rostedt , Masami Hiramatsu , Jonathan Corbet , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , Paolo Bonzini , Wanpeng Li , Vitaly Kuznetsov , Andy Lutomirski , Frederic Weisbecker , "Paul E. McKenney" , Neeraj Upadhyay , Joel Fernandes , Josh Triplett , Boqun Feng , Mathieu Desnoyers , Lai Jiangshan , Zqiang , Andrew Morton , Uladzislau Rezki , Christoph Hellwig , Lorenzo Stoakes , Josh Poimboeuf , Jason Baron , Kees Cook , Sami Tolvanen , Ard Biesheuvel , Nicholas Piggin , Juerg Haefliger , Nicolas Saenz Julienne , "Kirill A. Shutemov" , Nadav Amit , Dan Carpenter , Chuang Wang , Yang Jihong , Petr Mladek , "Jason A. Donenfeld" , Song Liu , Julian Pidancet , Tom Lendacky , Dionna Glaze , Thomas =?iso-8859-1?Q?Wei=DFschuh?= , Juri Lelli , Marcelo Tosatti , Yair Podemsky , Daniel Wagner , Petr Tesarik Subject: Re: [RFC PATCH v3 08/15] sched/clock, x86: Make __sched_clock_stable forceful Message-ID: <20241120145904.GK19989@noisy.programming.kicks-ass.net> References: <20241119153502.41361-1-vschneid@redhat.com> <20241119153502.41361-9-vschneid@redhat.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20241119153502.41361-9-vschneid@redhat.com> On Tue, Nov 19, 2024 at 04:34:55PM +0100, Valentin Schneider wrote: > Later commits will cause objtool to warn about non __ro_after_init static > keys being used in .noinstr sections in order to safely defer instruction > patching IPIs targeted at NOHZ_FULL CPUs. > > __sched_clock_stable is used in .noinstr code, and can be modified at > runtime (e.g. KVM module loading). Suppressing the text_poke_sync() IPI has Wait, what !? loading KVM causes the TSC to be marked unstable?