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 13BA235EDBD for ; Fri, 31 Jul 2026 08:47:12 +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=1785487636; cv=none; b=Fpl9yRdLkDyCGjMLmqJwVKjFPrRvz7UZNM2yDB2dIDkIijqwbtQ4tOdrDdlDfUAKynkxEXn+kl0ZVta1E5ImjUumih9SZgQZ7yr2wxiYOUUEGlO9D8tlF39kREuk0AQUaH1pZbatEB5+YUgGDSug+nDI2yLw/C8kxmnVIValpVo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785487636; c=relaxed/simple; bh=jAzRaFZ8oEFowV/7PhXfUh4UY7mVG+fETCn2hmyXOHE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=HJ1OyrWB8uj576gMSpAhHSWe5ALREhPiRxP9s3idTOhZuI6K4Rhh8xJXI0cyiTf8c2WvwYHaPPwW7xurNATrk2bMcevx4w6P8ly3yKPSZclIqW0ifZVFKP8L0ErrLnWV4PFd9gIjbcy5N1zNtH3IJXhq9c6pKTVd6FCJAC0Uwpc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=pass smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=FrPIDzPm; arc=none smtp.client-ip=90.155.92.199 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=pass 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="FrPIDzPm" 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=c0AF1oV8DwIVPDtWMEZEwQvz+kxuY6eKI3eJ0yDBY+8=; b=FrPIDzPmGSQp46r2bX84RCGuZF 9fmpXcZv+E3v3ZXpUyXrKTxeiZjOOa8WHkuZwluFldVZbL4hKHl7sWxwDgNC2JUG6Q/wNnKhHw8ab CMJutFIV52SN+arbBeSZvBFtJ+AF24Baq0VyafUT1g8ntpVNI9NK0i8tAYAZrqcVNWyVsms5Oyub/ 4A0+KIcCxncsoqQ1EZMNsV6+lJxdlL0mMrrQiqSYbb5OGP2L6woLCNZwYzoBK8sPcK2G1Snd5ILat xdvv2/U2eQUryG6An4IHHfo66LSvCemS3iHw0C0loDuuX1WGcdy1j6YHUtHTz6K9hsq5sUm0TC17k x39fcFEg==; Received: from 77-249-17-252.cable.dynamic.v4.ziggo.nl ([77.249.17.252] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.99.2 #2 (Red Hat Linux)) id 1wpitO-00000007K8h-2TRo; Fri, 31 Jul 2026 08:46:59 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 017003004AB; Fri, 31 Jul 2026 10:46:57 +0200 (CEST) Date: Fri, 31 Jul 2026 10:46:56 +0200 From: Peter Zijlstra To: Borislav Petkov Cc: Rik van Riel , Dave Hansen , Andy Lutomirski , Thomas Gleixner , Ingo Molnar , x86@kernel.org, linux-kernel@vger.kernel.org, kernel-team@meta.com Subject: Re: [PATCH] add tlbi=off to disable INVLPGB Message-ID: <20260731084656.GF776954@noisy.programming.kicks-ass.net> References: <20260729204341.3eb0b5ea@fangorn> <20260730014412.GEamqsbL46iteL25as@fat_crate.local> <20260730103227.GC751831@noisy.programming.kicks-ass.net> <20260730162318.GAamt6ds0siEVGwWlw@fat_crate.local> <20260730173104.GB776954@noisy.programming.kicks-ass.net> <20260730182439.GCamuW53V0HJHXNRqF@fat_crate.local> Precedence: bulk X-Mailing-List: linux-kernel@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: <20260730182439.GCamuW53V0HJHXNRqF@fat_crate.local> On Thu, Jul 30, 2026 at 11:24:39AM -0700, Borislav Petkov wrote: > On Thu, Jul 30, 2026 at 07:31:04PM +0200, Peter Zijlstra wrote: > > But also, nah: > > > > https://support.arm.com/documentation/dui0802/b/A64-General-Instructions/TLBI > > > > "TLBI - TLB invalidate operation." > > Yap, that's what I meant. > > > tlbi={ipi,broadcast} > > > > Anyway, INVLPGB stands for INVaLidate PaGe Broadcast, ain'ted that hard > > :-) Also, you know who to complain to for that instruction :-) > > Too late for that. :) > > "tlbi=broadcast" is a bit much to type: imagine you're hunched over some box > in the server room, like Spiderman, crouching between racks and balancing the > keyboard on some old pile of cables... :-P There is IPMI and other fancy remote management stuff these days. There is no reason to suffer hearing loss for entering server rooms anymore :-) > So how about shorter: > > "tlbi=bcast" > "tlbi=ipi" > > ? > > We probably won't need to write "bcast" at all, actually, because that would > be the default. So "tlbi=ipi" only. Yeah, that's good. Didn't we have a case where INVLPGB was disabled due to firmware or something? I was thinking tlbi=broadcast could be used to force enable it or something. Anyway, if that case don't exist, then yeah.