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=1792592384; b=baeTqWLD/iKIKD8na/ev4Pde8tp9ixRy2ZPEE/e8WHUOv4PWZGKI15Pb1DpZfzZcgMTz EdCxv4GP8m40sd5jJs2oabvgmySC+K1GkiWolK35Unh1d/kx7XY80Fp9Cj9RFqJ+/qweZ 6SNOPHG4B3Lda899NIdT6yQy7ICTN+5Sz15LNL/UKaixnFNG2F88J6IKGx70Woct2GQHV hq5do2nmoLFko1VbV37eU6WXnrzyHQSqCULVXY7lilNwX1kcuvdmc9GClzjpL+pf4DNfO QlJueTw59956JJAZWLzpbaZorF8ScsNSckEHP+w4poMt5upQj+mw8eXRFDYB+KNiHAg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792592384; h=Received:DKIM-Signature:Received:Date:From:To:Cc:Subject:Message-ID: References:MIME-Version:Content-Type:Content-Disposition:In-Reply-To: X-Cookie; bh=UEVidBOtJkGIF4/dj6UUdp9Wd3YXp7nSAWdH8eAbb7E=; b=Ly2p/rTsL+1lMwRWovJw4mjRdai5fAll+Qgl1Y/LRXvJLFDqoORw5UR80nktEhftC2Rm 58V5vHVHyaBaWw32YS6vv2/0P8dIvVORZWtgLw0VDLdDvXS+kIFJPhoAOYEkckePWGf+u 9E+k+ZhbkcM9eaR9Ysj0FtfXju559oOW7uwR7I2VrSlChWb7dmkxg5AdWu/Wq9qFlhjQo cToVjXWcf0qEuhZAsUtaPLghwxqBnq4TMhWSekqUZi/Zp5da+ENKBrMhi2emTVwjZcOFD Wb1nsmv+mtYOl70Fa8//MlJrkZtImTjL6ARmdCzOoo+7waiM0EIhW6ReimRtWJxKYBg== 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=J3YF5IEx; 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 8956E606A31A; Wed, 21 Oct 2026 14:19:44 +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=J3YF5IEx Received: by smtp.kernel.org (Postfix) with ESMTPSA id 091A11F000C4; Wed, 21 Oct 2026 14:19:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792592384; bh=UEVidBOtJkGIF4/dj6UUdp9Wd3YXp7nSAWdH8eAbb7E=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=J3YF5IEx+f0xM3L6lGSedpqw1xZILeSBg9+qBCG3fPIh0Im2Qi3dVV9QwWk54g/Ow f/fUNUXG/IWtyORuoTDz/YC8zut+S8kBe6l1nKAWd7K/7O2DnxERSzSwOIDxd2Ky3G OUulGror7/GFlnXow42JXkVC36VdSWTiDalLfNb5CUi7HyDHauAuKmy49J+FBWi9g6 y4SJUN4A6JfdAQJTet1Qwm7VwdtzEGpW3oYwNZFsIzB7LhhUrderhVq4JJdV+kozwK csXe7/1qYnBwKEZUDeAzIzzLb+VQ+mOYFntgFWrhkFs+ohgXlcTtqYfQ61laSvDyeI 36QCVCxA9FeNw== Received: by traversing.sirena.org.uk (Postfix, from userid 1000) id D42661CB526D; Wed, 21 Oct 2026 15:19:41 +0100 (BST) Date: Wed, 21 Oct 2026 15:19:41 +0100 From: Mark Brown To: Marc Zyngier Cc: Fuad Tabba , Oliver Upton , kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, Joey Gouly , Steffen Eiden , Suzuki K Poulose , Zenghui Yu , Catalin Marinas , Will Deacon , Mark Rutland , Lorenzo Stoakes , Fuad Tabba , linux-kernel@vger.kernel.org Subject: Re: [PATCH v3] KVM: arm64: Sanitise ID_AA64MMFR3_EL1.S1P[IO]E Message-ID: References: <20261020064306.1542865-1-fuad.tabba@linux.dev> <86mrs7ywsc.wl-maz@kernel.org> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="myDSwi2Ph81d1HS6" Content-Disposition: inline In-Reply-To: <86mrs7ywsc.wl-maz@kernel.org> X-Cookie: Whoever dies with the most toys wins. --myDSwi2Ph81d1HS6 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Wed, Oct 21, 2026 at 03:04:51PM +0100, Marc Zyngier wrote: > Mark Brown wrote: > > It would be nice to have it be more obvious to the VMM and/or it's users > > that it messed up, as things stand features it thought it had set will > > just silently vanish from the guest - they'd need to know that this is > > something that might happen and check after finalization or similar. > > That's probably more a documentation/education thing than anything for > > the patch. > The VMM is an integral part of implementing the architecture. If the > VMM doesn't cooperate, that's its problem. Absolutely, it's a bug if the VMM is doing this. What I'm saying is that it could be helpful if the bug was made visible, with the silent fixup VMM bugs could easily lurk around for longer before someone notices the problem than they might otherwise. --myDSwi2Ph81d1HS6 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYKAB0WIQReagvpf3TrrA7BoYYv73Ows9A4iQUCatjJ+AAKCRAv73Ows9A4 iZeYAQDZSaktjduuIlbdaY9J9HfNbTXXohL5Mg9RtMggk2fZTwD/RWuP/83tS3ju xCr8sa/Wa91fFPcj6epcub0Aat5XBAo= =KMvg -----END PGP SIGNATURE----- --myDSwi2Ph81d1HS6--