From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 62101CDB466 for ; Thu, 25 Jun 2026 09:54:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Type:MIME-Version: References:In-Reply-To:Subject:Cc:To:From:Message-ID:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=EQvzmhzhY00voWSBNdbfxNOmR53Cza+WLYkpg4Exsw8=; b=Pp0DgrOWbDwPRqsBTdyvygiB95 QDkU24xVjFnPaIQ4q046Q84L4CZ7lxi8cbtL3sMLprlR0bc0jMGdWONqHcsb84K9CcZxb5Z3YS5NG z5WMZr66+RtBGjoJQJNMLR1XcXNbbh/Z2OuXXXdRRubOYgW9hspbx3i9MzDcxSUeTcBAr1VSQL3SE IdiZzrFZF9N7bMcJQN19b4uJ01gbLeBe8hd9tcgEQsOuvm6r9qRWop8rBHypAwDmTLchco47nqmAW CPrRkw7zrNlEYnEUGqhmuytzKB7huKX6T2QCDbkN8lvZteb4r7ff5ZFW9UF34wsnmy4q/fQ6uezrA s4Ofg0ig==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wcgnG-00000008wx2-3F8r; Thu, 25 Jun 2026 09:54:46 +0000 Received: from sea.source.kernel.org ([172.234.252.31]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wcgnE-00000008wwo-39rT for linux-arm-kernel@lists.infradead.org; Thu, 25 Jun 2026 09:54:44 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 09CE640691; Thu, 25 Jun 2026 09:54:44 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DECA11F000E9; Thu, 25 Jun 2026 09:54:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1782381283; bh=EQvzmhzhY00voWSBNdbfxNOmR53Cza+WLYkpg4Exsw8=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=cW1YDz4iq0eX1gwdCXa4sHqGm/2nXwLngx4dLAAamShH0CkGnA4LN1QTNU1VNP1Vk gbiNRfi2VcobYiBb9/4nqs1lJLwbJDRPbvd/xLAKtlG8jDQwNsqm0HanEa+sWn6aj/ FP4npsdEgKO98Ab3bKpqCdKS7sysAE5s2Hj08S7R19gdwEV70fFNQEd//xANPzfLjy qsGq5mC/vKyBsF/vKU0ip5KuaKWxZIYO6qzOsU1Zw19rTzjYqNnawjCkyOnaF9f/Ta nHo8iUkndGzQ1tk/mO0LZsKIxwbbcIy3btBGY2DMDbSU9ENzm+/pX5Scjc0iqKaxih scYE5jx11Azlg== Received: from sofa.misterjones.org ([185.219.108.64] helo=goblin-girl.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.98.2) (envelope-from ) id 1wcgnB-0000000Fvck-0oXg; Thu, 25 Jun 2026 09:54:41 +0000 Date: Thu, 25 Jun 2026 10:54:40 +0100 Message-ID: <86h5mrq71b.wl-maz@kernel.org> From: Marc Zyngier To: Wei-Lin Chang Cc: Itaru Kitayama , linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org, Oliver Upton , Joey Gouly , Steffen Eiden , Suzuki K Poulose , Zenghui Yu , Catalin Marinas , Will Deacon Subject: Re: [PATCH 0/3] KVM: arm64: nv: Shadow ptdump fixes In-Reply-To: References: <20260623142443.648972-1-weilin.chang@arm.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/30.1 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: weilin.chang@arm.com, itaru.kitayama@fujitsu.com, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org, oupton@kernel.org, joey.gouly@arm.com, seiden@linux.ibm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, catalin.marinas@arm.com, will@kernel.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, 25 Jun 2026 08:47:04 +0100, Wei-Lin Chang wrote: > > I don't see a way out with this per-mmu file scheme. The core issue is > mmus have a different lifetime than the VM's debugfs directory, and > both's removal can happen in parallel, i.e. the VM debugfs directory > can be removed anytime we are in mmu notifier release freeing the mmus > and their shadow ptdump files. Why isn't that a problem with the existing S2 ptdump code? M. -- Without deviation from the norm, progress is not possible.