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 ACAFE381BA for ; Fri, 19 Sep 2025 09:58:17 +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=1758275897; cv=none; b=vFXzVcqOqsUEQkcOJ/VBp7L4paFa1KVZL9emXyH8726fpo16Y1VjghvxGOTimK0nti9lxM5UYoEd+x+uEWOHGxPTA3aav064upGSez0lbhWnQ151QcODjqUV403u5FOTJzZmSQjwFTYqob65WcjS2YyIcU90NePIMQLyOhBfZBM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758275897; c=relaxed/simple; bh=ivM4qF0m8X/HkIH4I9LDYLt3xplTvDGm7A0Fo6xic/s=; h=Date:Message-ID:From:To:Cc:Subject:In-Reply-To:References: MIME-Version:Content-Type; b=gkG/GlF3KAL/euG5rIHUzP2ylJ0CaPzdxg5ixVDfH1/RxZV8JAtdzPrasxkc4vC3pEBRVJrwd/J/auJTt2Xp8kfaDTAaHliH6iXMxKk6/tL2Mk+/ql5yKjd5/2xeGWV6/QBTCHq2P0TwXZLgQWHmkKTV0n+mmON905MEKhed5OA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=lvNDwyGR; 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="lvNDwyGR" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 17E8FC116B1; Fri, 19 Sep 2025 09:58:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1758275897; bh=ivM4qF0m8X/HkIH4I9LDYLt3xplTvDGm7A0Fo6xic/s=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=lvNDwyGRSlhQ8B1Y9BXmWd1HxbXDEf+8T0ONy2eCsLXO6QM29Hw9xGBEVGRAnp+TG X5ds/3srUDtGIFWdTppjsSAScw0o4vGyXuy5RWIGodQFeMG50DHW0N91TW9ErAvjl3 5rvjb7sbunbjUT1VE0iheAJ39Kd7a3F02eR2zGn1kgEUc/Cq7cskp2NwW97wE+sFZL WxR6f9yEElJ8sfvZFZoy5MHCb2siPIt+W1/Q4LAfmLyoCFBOE8I0EjOZdSY5lvZ+B+ 5197ncTifJd3wIStQu8A0LwqDVocc7PB3aKC991D67DJJKnJxmHJNKX3Jmj8s0gByl D3aXUs9jra9Ug== Received: from ip-185-104-136-29.ptr.icomera.net ([185.104.136.29] helo=lobster-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 1uzXsc-00000007jNP-3lWH; Fri, 19 Sep 2025 09:58:15 +0000 Date: Fri, 19 Sep 2025 10:58:13 +0100 Message-ID: <875xdezruy.wl-maz@kernel.org> From: Marc Zyngier To: Oliver Upton Cc: kvmarm@lists.linux.dev, Joey Gouly , Suzuki K Poulose , Zenghui Yu Subject: Re: [PATCH 0/2] KVM: arm64: nv: Fix SError injection at EL2 In-Reply-To: <20250918164632.410404-1-oliver.upton@linux.dev> References: <20250918164632.410404-1-oliver.upton@linux.dev> 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: kvmarm@lists.linux.dev 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: 185.104.136.29 X-SA-Exim-Rcpt-To: oliver.upton@linux.dev, kvmarm@lists.linux.dev, joey.gouly@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false On Thu, 18 Sep 2025 17:46:30 +0100, Oliver Upton wrote: > > FEAT_NV2 keeps us out of the loop on changes to HCR_EL2. That really > sucks when the guest hypervisor toggles bits that affect the hyp > context, such as TGE and xMO. > > The architecture now allows an implementation to treat HCR_EL2.AMO as 1 > any time that HCR_EL2.{E2H,TGE} = {1, 0}, effectively allowing us to > hide what would otherwise be a quality of emulation bug in SError > injection. Yup. Note that the same relaxation also applies to IMO/FMO (that's the reason why this relaxation was originally introduced), but I don't think we need to do anything on that front. > Unfortunately there's nothing to be done for E2H0 VMs, although given > the direction of the architecture the offending hypervisor should just > get with the times... I have no sympathy for these either. Eventually, they'll get on with the program, or experience the fate of 32bit... I'll drag this into 6.18. Thanks, M. -- Jazz isn't dead. It just smells funny.