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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 477C7C43219 for ; Tue, 1 Nov 2022 14:30:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229894AbiKAOaV (ORCPT ); Tue, 1 Nov 2022 10:30:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45062 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230221AbiKAOaU (ORCPT ); Tue, 1 Nov 2022 10:30:20 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 32990110B for ; Tue, 1 Nov 2022 07:30:19 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id CF5DBB81DCD for ; Tue, 1 Nov 2022 14:30:17 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8475AC433D6; Tue, 1 Nov 2022 14:30:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1667313016; bh=3LAJDs979R00Ilp45b0EmBktYqQOpB3tKEAn3nqXH+Y=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=JzwVNlPo2X0ZQXG4axJRPfCip4oWF0q5g/a0wwbVvlp19gqJTiLKvPb2bl/WM/fBf 0n+gb8inkhXaNuN4RR7iTRAQExuyf4h1mt6xFPWQN0xUgz951jAF4sXxjbqsypx2oE OVQiOn7bGd5cSF/p3sSO/VZD8rVkrkrhaJ8cs7KBV5Ox9SpOwc9RnikfpmkA07QymB A/ttWkI/IsaCU1LMoieXE4sFzy+U8gwiTTw3KiZ9Fcy9iz0dTP3Yz+pTaLSZOOseXH BMB5H/pcM+xmZt5c4Cr2xRoHDCPh6TbD9rqM2bhG484LUh8ZRAxUbsK12l/LtGTEwR tXcGxTrPy9afQ== Date: Tue, 1 Nov 2022 14:30:09 +0000 From: Mark Brown To: Marc Zyngier Cc: Catalin Marinas , Will Deacon , Peter Maydell , Richard Henderson , Vincent Donnefort , James Morse , Alexandru Elisei , Suzuki K Poulose , Oliver Upton , linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, stable@vger.kernel.org Subject: Re: [PATCH v2 2/2] KVM: arm64: Trap access to SMPRI_EL1 and TPIDR2 in VHE mode Message-ID: References: <20221101112716.52035-1-broonie@kernel.org> <20221101112716.52035-3-broonie@kernel.org> <86bkpqer4z.wl-maz@kernel.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="SakqH1ZP7qWQfyDo" Content-Disposition: inline In-Reply-To: <86bkpqer4z.wl-maz@kernel.org> X-Cookie: Do not write below this line. Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org --SakqH1ZP7qWQfyDo Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Nov 01, 2022 at 01:33:16PM +0000, Marc Zyngier wrote: > Mark Brown wrote: > > - if (cpus_have_final_cap(ARM64_SME)) > > + if (cpus_have_final_cap(ARM64_SME)) { > > write_sysreg(read_sysreg(sctlr_el2) & ~SCTLR_ELx_ENTP2, > > sctlr_el2); > I still question this. As far as I can tell, it only affects the host > context (HCR_EL2.{E2H,TGE}=3D{1,1}). > This is outlined in the description of the HFGWTR_EL2.nTPIDR2_EL0 bit: Oh, I see what you meant there - I was purely focusing on the new code with the fine grained traps, not the existing code. > So I can only conclude that messing with SCTLR_EL2 is superfluous and > doesn't affect the execution in a guest context. Yes, if you look at the pseudocode for TPIDR2_EL0 that's the case. It's either EnTP2 for HCR_EL2. =3D=3D '11' or the fine grained trap otherwise. > > + /* > > + * Enable access to SMPRI_EL1 - we don't need to > > + * control nTPIDR2_EL0 in VHE mode. > > + */ > This comment is factually wrong. Bah, I fixed one but not the other sorry :/ > Date: Tue, 1 Nov 2022 12:19:51 +0000 > Subject: [PATCH] KVM: arm64: Fix SMPRI_EL1/TPIDR2_EL0 trapping on VHE >=20 > The trapping of SMPRI_EL1 and TPIDR2_EL0 currently only really > work on nVHE, as only this mode uses the fine-grained trapping > that controls these two registers. >=20 > Move the trapping enable/disable code into > __{de,}activate_traps_common(), allowing it to be called when it > actually matters on VHE, and remove the flipping of EL2 control > for TPIDR2_EL0, which only affects the host access of this > register. >=20 > Fixes: 861262ab8627 ("KVM: arm64: Handle SME host state when running gues= ts") > Signed-off-by: Marc Zyngier > Cc: stable@vger.kernel.org Reported-by: Mark Brown Reviewed-by: Mark Brown --SakqH1ZP7qWQfyDo Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAmNhLXAACgkQJNaLcl1U h9AZmwf+N1nF+pmaVTPljAPEIm4DDRTBMXDEH0Ypx4lq4ugpz+j/dSra11ucYvbL i7ePrcuyLFHyhONPPFspFlfaTu9fO5laFRCTi8pLu8OH2kEAsiITWgrWaSVNRzd7 btOxblRhE3FeBXkfaeDpHNwcXL90PrqAjLWz5zXz+LzpRZvNwifCBkCstkPdd5lB /SetA9yvyrOHBmtiqFlf48Fnls2ny4yhCTIsVeSpN6KLV6mq8CnlaPjcrcFtOrm8 k8IFXxrAmDQGG+YCfKQl1yIiii8p6h5iFTy0A9xHA4/5TrdhW1vM12nv3FBpXcno +9QIzr0upuTU5YhTPfHm9UqJI3h1gg== =G3hK -----END PGP SIGNATURE----- --SakqH1ZP7qWQfyDo--