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=1793271538; b=IqxQrk3sc0w9Ti3qcJuvUk2uFo3Jpr45s7jxvTGfTv0Sp1eR/UELAuSNrABB9keAkRx3 nLITKGIpcu2V3d6erUkWlmPk1v2VXsU6KKdXeFkufUPfHBcYWDNVxo9MXr85/2q1+EtSz mhBfKEZycqQebozUFDW6iX8jRDTg6GyffYK6QPAjTLRUTFrrcgFHy+eNakUfztLuYuhzS ojm2EaBVZaJyXqZQ3/oONuSViH288pyx2exWtYbx0OL6IsIXyLypfUxrvbFLxOnqY4tyr 7TtX52yLBHh4QocGTy5Vpwa4M18vtx0Vdfzua4iSq1lvhtNAFwm1qW2j78qeYTNDg6w== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793271538; 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=wqIKNGVdfkrptWgaeVqfIbbOwYH/8dZpAy0/6WAuLr0=; b=Ys71h8GBVzEFHXhUE1ueNDtn/VqzOGC5PN5HS43BJxvQh5ealyL7TJ0P9HDGw0La6+vc Gj1uappE9oIvcUUW2ikdJtlZrMHi07pd4t1G/bHVx9vJpfYmrFo7sfDd0W6sj5fKm7dTC 56xv5eqze/1FRHWTSjQAHCfVY9Br2lOCNH0nGk2ZbSInemSBbaJNLhXNPuKpmd4auLxCj hMkYL23jRtOlLR2cqjEuWFzlurTPvcg4HSpr+F907ztBKnpoFHKHgTxSOl0DKmkhX7/ic /unJuhamdVUldrCymbNcJUSm4BmIg4TK2v3Qh590GWGg27Tgjjeul2x7iyQEjkY94jg== 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=DbfAITP4; 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 D9098606A31A; Thu, 29 Oct 2026 10:58:57 +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=DbfAITP4 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7DA561F01825; Thu, 29 Oct 2026 10:58:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793271537; bh=wqIKNGVdfkrptWgaeVqfIbbOwYH/8dZpAy0/6WAuLr0=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=DbfAITP43mnXujBkidMw1VXT0oNbo+tpg3tR7bOzuB780AUdvqY+4em7GNuqMVOI+ /9vGGFvYxJY5nv19x76EiMaaU1pupbb1TeKxwBv+eDDJBW+lowrvUiosMqB0muLJDW oZQWE3axBw/T5ZXch13QlCuLU7/TDES9r0SttwBTwdbHbLtVwP1u/mOQkPRVt4XU2z ka6PUf3+V44mkBpgZSLH4FKh4jweRumvj5WYSzqCEr+yd0ypovmx2zsWCiiiS0+I+3 IEv383ypRf+4xMjQmzXKY5eYg5em8s4etsSqBuns5rZdxDKxvWmld57KIgVwGY9V0n RdjEAQ+sCyDtA== 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 1xMNqR-00000008VQy-0rgy; Thu, 29 Oct 2026 10:58:55 +0000 Date: Thu, 29 Oct 2026 10:58:54 +0000 Message-ID: <86ld7gydqp.wl-maz@kernel.org> From: Marc Zyngier To: Fuad Tabba Cc: Oliver Upton , kvmarm@lists.linux.dev, Joey Gouly , Suzuki K Poulose , Zenghui Yu , Wei-Lin Chang , Steffen Eiden , stable@vger.kernel.org Subject: Re: [PATCH] KVM: arm64: nv: Respect HA when computing translated TCR In-Reply-To: References: <20261029090522.64662-1-oupton@kernel.org> 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: kvmarm@lists.linux.dev 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: fuad.tabba@linux.dev, oupton@kernel.org, kvmarm@lists.linux.dev, joey.gouly@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, weilin.chang@arm.com, seiden@linux.ibm.com, stable@vger.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 Thu, 29 Oct 2026 10:05:19 +0000, Fuad Tabba wrote: > > Hi Oliver, > > On Thu, 29 Oct 2026 09:05:22 +0000, Oliver Upton wrote: > [...] > > diff --git a/arch/arm64/include/asm/kvm_nested.h b/arch/arm64/include/asm/kvm_nested.h > [...] > > @@ -29,7 +29,8 @@ static inline u64 translate_tcr_el2_to_tcr_el1(u64 tcr) > > (tcr & TCR_EL2_TG0_MASK) | > > (tcr & TCR_EL2_ORGN0_MASK) | > > (tcr & TCR_EL2_IRGN0_MASK) | > > - (tcr & TCR_EL2_T0SZ_MASK); > > + (tcr & TCR_EL2_T0SZ_MASK) | > > + ((tcr & TCR_EL2_HA) ? TCR_HA : 0); > > } > > Should you forward SH0 in this patch as well? It's missing here, so > the walks are Non-shareable, and looking at the ARM ARM, this would > make every hardware Access flag update CONSTRAINED UNPREDICTABLE > (R_WLTNL, and the IsWBShareable() check in AArch64_S1Translate()). An > L1 that programmed SH0 as Inner Shareable could then take an > unsupported atomic update fault. That's a good point. However, my reading of the ARM ARM indicates that as long as S2 shareability is Inner-Shareable, the resulting shareability is Inner-Shareable (see R_ZNLRJ), so we're actually safe. This should be fixed though. > HPD isn't forwarded either, although at.c reads it from TCR_EL2 for an > E2H=0 guest. Was that intentional? Another bug (E2H==0 really doesn't see much love). This needs fixing, but also relies on sanitising TCR_EL2. Thankfully, there is [1] which requires some reviewing... ;-) Thanks, M. [1] https://lore.kernel.org/r/20260917214215.74135-1-weilin.chang@arm.com -- Without deviation from the norm, progress is not possible.