From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 2DA3B3B38A9; Tue, 10 Mar 2026 16:50:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773161425; cv=none; b=gW60v7p8esFlXErpG1J1qjl12IB9G/xccyUBLGkpL+TD/82aEmGbBRVvObMOVFXG1y/xZuHqd6STiZX4wySkS5te+DWjwWv3E7lT3qaw3qmVfvUw9tEWDedsdHbayChXqSrEEmdN4bgoAEXLXVppo7HDVvu6JjUmTT9XbEX85pg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773161425; c=relaxed/simple; bh=63jyBytLUR+i/lBx8xB06KCEs0ZPeYJ2c2pno8lKA2Y=; h=Date:Message-ID:From:To:Cc:Subject:In-Reply-To:References: MIME-Version:Content-Type; b=F0wghsRLAEo/daNB7cRnWp2F+siAQ/biaGqwjhdUZtB7mk0Qf/RJx9VQ2ZX18ZKdiRnzkxJTRhqhYuxkDP2hIwG1S70wzTsHSVn1PaNjDFtgkKYzKuC+BecWN7K69NUhBjCSbfBRvMhzCfPQksm29GTi2fljY8WhpRtMSJFOqWY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=H1ZTJD2c; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="H1ZTJD2c" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C49ABC19423; Tue, 10 Mar 2026 16:50:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1773161424; bh=63jyBytLUR+i/lBx8xB06KCEs0ZPeYJ2c2pno8lKA2Y=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=H1ZTJD2cZrCrN0dUV3oOcdFSF7HE2Prlvnd9N0z+j1ZW5sugWTWx7VsJ8n5qoErKS M6qT644sZKMQ6VYclH69y+7CLlfm4hfn/T8Ef1upsdoD18zpNiJFsUvGia2Sf05nhk V7bEQiy5lcta2nis1EEZrkKKZjxZuG5aqnykwlNP3wR4tsWjKuUKlfmJOfCQG8nPqJ d0M2SsKJleGjDdJ1GsXNXH0+8Iid/hB3Lm2j+g1exJtE+RFuZvpyQm1Jew9AL8aSt+ ZOPtdsS33TOfVhzc+49S05SU9glAv0XJlDcmB1aIeNA8eK6auP5UQgvGyJltdAOJiE TMqzS0JHS36vA== 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 1w00Hm-00000000Xkq-1nlO; Tue, 10 Mar 2026 16:50:22 +0000 Date: Tue, 10 Mar 2026 16:50:22 +0000 Message-ID: <86bjgv7ho1.wl-maz@kernel.org> From: Marc Zyngier To: Wei-Lin Chang Cc: Joey Gouly , linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org, Oliver Upton , Suzuki K Poulose , Zenghui Yu , Catalin Marinas , Will Deacon Subject: Re: [PATCH RESEND 2/2] KVM: arm64: nv: Expose shadow page tables in debugfs In-Reply-To: References: <20260308231829.864983-1-weilin.chang@arm.com> <20260308231829.864983-3-weilin.chang@arm.com> <20260310152604.GA3093715@e124191.cambridge.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) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: 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, joey.gouly@arm.com, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org, oupton@kernel.org, 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 On Tue, 10 Mar 2026 16:17:07 +0000, Wei-Lin Chang wrote: > > On Tue, Mar 10, 2026 at 03:26:04PM +0000, Joey Gouly wrote: > > > diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h > > > index 5d5a3bbdb95e..f88f6c4d646e 100644 > > > --- a/arch/arm64/include/asm/kvm_host.h > > > +++ b/arch/arm64/include/asm/kvm_host.h > > > @@ -217,6 +217,10 @@ struct kvm_s2_mmu { > > > */ > > > bool nested_stage2_enabled; > > > > > > +#ifdef CONFIG_PTDUMP_STAGE2_DEBUGFS > > > + struct dentry *shadow_pt_debugfs_dentry; > > > +#endif > > > + > > > /* > > > * true when this MMU needs to be unmapped before being used for a new > > > * purpose. > > > @@ -405,6 +409,9 @@ struct kvm_arch { > > > * the associated pKVM instance in the hypervisor. > > > */ > > > struct kvm_protected_vm pkvm; > > > + > > > + /* Nested virtualization info */ > > > + struct dentry *debugfs_nv_dentry; > > > > Seems like this could be guarded with CONFIG_PTDUMP_STAGE2_DEBUGFS too, or is > > there a reason you didn't? > > Right, I was thinking this "nested" directory can also hold other NV > related information in the future, that's why I didn't keep it behind > the option. We can cross that bridge when we get there. In the meantime, I'd side with Joey and would rather not have a dangling pointer. Thanks, M. -- Without deviation from the norm, progress is not possible.