From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793003410; b=1/g//3nLN4OPXj9L4q4rfBwWrAkgwdWeQlqTIlgHsy3IvS5XmljfgJfxtCF6g/s28z0G nnpbNNcfh+1FUo1mPhOXGFgOdZyIF+wXNzJqMwgFEkPl3ixxDletcgQ9pNq9/W0ALJQJq YeZhI9u0+hFLV0oLagL0D2Fqx5f0eqN4KnObPZBlkLZscxSB6miwU0Ckt2UBoCifXzISJ 8LMlJOirA+4wBPNJTaN8Yt7RYQG9PwD96XPaydY/ukz97Qm0hFAd0I4Ax5uuJhlSIHYTB oqIbXpNyrMk0ucSlpb+h6LAAvN0Uug4TFXPxghn48+HJbV4J81rBM0/X5be6Wge44ng== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793003410; h=Received:DKIM-Signature:Received:Date:Message-ID:From:To:Cc:Subject: In-Reply-To:References:User-Agent:MIME-Version:Content-Type: X-SA-Exim-Connect-IP:X-SA-Exim-Rcpt-To:X-SA-Exim-Mail-From: X-SA-Exim-Scanned; bh=G63bq4wpgZslgc8Jrbf5zqBVwNjBpTm05EKH4grfb9g=; b=NFmlvwjOy7lmBgJG9AS9vbdK72ginn+ultA0bf/GnF7Pj3AxgQIDbeBMJEUA7NgWkCzv zD0dtPWVPijOdbHkgJYERUpjDcd4bWBr96IJp0zK1b5V4zOD7wDeM8uyGwGWQ+P6gZkea 1T/CDLJc0YOX04JqlJQrkzpCTUqgKDtHudg/Htpw/yeIRX/vBeAZ4c2qT3bwOz5d9yMNm QThQo67onFEqwAEyhh15lA7GMlwWnBIcRNpAwi3NIdzp/ikXIXV8W7EqYyvC0xy662msm 8iLiBvs2XHR0J2vULelbuliq726WhRNfiaomnaEJORaWl6Tnm1VqrqDMjMUzOfBIkfw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=eNjS8GtB; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 453E2606A32C; Mon, 26 Oct 2026 08:30:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=eNjS8GtB Received: by smtp.kernel.org (Postfix) with ESMTPSA id CFF321F01825; Mon, 26 Oct 2026 08:30:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793003409; bh=G63bq4wpgZslgc8Jrbf5zqBVwNjBpTm05EKH4grfb9g=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=eNjS8GtBeBPyA8EYl+0IroArRKZqddmttCe/pqhYkfWRzMvjs0xHUdFA5zBuwJ/dB cexNnd49Tts1u13A+p4i8tn4a6PQV0NVL4aKqOnr5UNq3cxWOoYv8fpIfiswUtP92d Z/9qaxzZpNLLPgIMFYE9xf3BEexK7pTS8AmZRw3kFDaXrDQy/VvVUq+JtED9OnVfGc ZydQEiSyZc1cxdXcaC5pdQtGfR9YCuabQKeK0u7lqpU5YbBU1ouoQYk3TpT3VuHNZj +NcclCy7JnHtweFs19IZK/1wJ01Z598SreYQSegk757HsENmnfVqZE/Na5wDhrrM/1 utx8qgxT6pVpQ== 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 1xLG5n-00000007ABg-2krT; Mon, 26 Oct 2026 08:30:07 +0000 Date: Mon, 26 Oct 2026 08:30:07 +0000 Message-ID: <861p9czwxc.wl-maz@kernel.org> From: Marc Zyngier To: Itaru Kitayama Cc: Paolo Bonzini , Sean Christopherson , Shuah Khan , Oliver Upton , Fuad Tabba , Joey Gouly , Steffen Eiden , Suzuki K Poulose , Zenghui Yu , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev Subject: Re: [PATCH v3] KVM: arm64: selftests: Test VNCR translation invalidation In-Reply-To: <20261026-b4-vncr-mapping-test-v3-1-7c094a00d46e@fujitsu.com> References: <20261026-b4-vncr-mapping-test-v3-1-7c094a00d46e@fujitsu.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) X-Mailing-List: kvm@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list 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: itaru.kitayama@fujitsu.com, pbonzini@redhat.com, seanjc@google.com, shuah@kernel.org, oupton@kernel.org, fuad.tabba@linux.dev, joey.gouly@arm.com, seiden@linux.ibm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false On Mon, 26 Oct 2026 03:10:10 +0000, Itaru Kitayama wrote: > > Add a standalone KVM selftest that checks VNCR accesses after L1 > updates its stage-1 mapping and issues a TLBI. This guards against > stale VNCR translations, as KVM caches L1's translation of > VNCR_EL2 and must drop it when L1 invalidates the mapping in > kvm_handle_s1e2_tlbi(). > > Keep VNCR_EL2 unchanged while remapping its backing page A to B then > again to A. At each step, L2 reads and writes TPIDR_EL2, and L1 > verifies that the accesses reach the selected page while leaving the > other page unchanged. If you were tracking cross vcpu invalidation and exercising all the architecture corner cases (such as permission changes and co), that would be helpful. But as it is, it doesn't help much as a validation tool. Its scope is way too narrow. M. -- Without deviation from the norm, progress is not possible.