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 3FB7E4A06 for ; Thu, 9 Oct 2025 15:01:03 +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=1760022065; cv=none; b=TqApqH3i/MF07ONcGFn8Mn+mZmybIkpHubAloCbONc6PWeR8b46FoPtNIcIcy4c0twfDUBHgyaXhN+N0Wuzy4AYWHQjnsiJ97Im2p8Zr/vDEtjNxZG86anKl2SO5/LCDzgU4mjPhTIICwm9iuOcEKkdMXGLhOOSNqPmW9TGXKfs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760022065; c=relaxed/simple; bh=aCEs0dRnHnhXTkyiG9Y9GGrX/e2K7wl0i7DBunrYR+g=; h=Date:Message-ID:From:To:Cc:Subject:In-Reply-To:References: MIME-Version:Content-Type; b=nKn0tzTgFm4Msdq6GZ3VpIaWo5tS9xDLBVwJEO8rNNurMtgPtRFGqPpJuKo42iZsa3Ov7WtmKV533DVU9QIjWaDINIgOspJDmFL38aoAX0bYsLHe4uSySiRbGxJNgfug+R0yClpLglRyq107Q5WXbtNeimp2lG1F6U78xRJsX6c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ZoBbgZlA; 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="ZoBbgZlA" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B5B56C4CEE7; Thu, 9 Oct 2025 15:01:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1760022063; bh=aCEs0dRnHnhXTkyiG9Y9GGrX/e2K7wl0i7DBunrYR+g=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=ZoBbgZlAkzWTsM0CbfdgU55kAd32bfmGMGqpFjheLQt6QBAgwMpvZy4Ib9hcVhKHq pKWKpVDZ7VgVC1o/Zb4atJk/H34SUlKkkqSyvoGmcj6B2kBMEb7GnObDrw3QtgGnrz KJp2XXjc6A6xtKBNwFi8iIAR7Fnm6KvnGERmOjIj+V7VcyH4HxJfqYr+xLa4EpXE/H ioJA41c2WcFrYMF8FC6YJehNyjhojuXIAjXfnwmPLFFF7Myuz7uQtiskEbhM4Vt5TI MSzZ2+eR3QtlhKH8nstsBe+XcqsB7H3xBH4gWe6OdjdBjv2A7jFFQwhGQAMVeoTuB6 7h3iniCKgIZYA== 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 1v6s8b-0000000CfLA-3ZUG; Thu, 09 Oct 2025 15:01:01 +0000 Date: Thu, 09 Oct 2025 16:01:01 +0100 Message-ID: <86plawxgpe.wl-maz@kernel.org> From: Marc Zyngier To: Jan Kotas Cc: Oliver Upton , "kvmarm@lists.linux.dev" Subject: Re: KVM NV + SVE host OS warning In-Reply-To: <1BD0A29B-E20A-4BA9-A916-8B975813503C@global.cadence.com> References: <799DD5E5-8BC2-47B3-A919-33429D3FB2F1@global.cadence.com> <865xd61tt5.wl-maz@kernel.org> <864isq1r66.wl-maz@kernel.org> <25C5E00D-62BC-4188-8642-21913446B32C@global.cadence.com> <1271032F-41BB-4896-AAED-8660D5459E7D@global.cadence.com> <864is9zqs9.wl-maz@kernel.org> <677A529C-B3D7-4BD1-BEED-D8414D961BBD@global.cadence.com> <86zfa1y58i.wl-maz@kernel.org> <15A85F2B-1A0C-4FA7-9FE4-EEC2203CC09E@global.cadence.com> <86y0plxvt4.wl-maz@kernel.org> <86wm54xo1r.wl-maz@kernel.org> <1BD0A29B-E20A-4BA9-A916-8B975813503C@global.cadence.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) 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: 185.219.108.64 X-SA-Exim-Rcpt-To: jank@cadence.com, oliver.upton@linux.dev, 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 Thu, 09 Oct 2025 15:41:28 +0100, Jan Kotas wrote: > > > On 9 Oct 2025, at 14:22, Marc Zyngier wrote: > > > > As an alternative, and in an effort to keep at least VHE guests > > running on V2 (and other machines suffering from the same situation), > > I have posted a potential workaround at [1] for the guest to reliably > > detect the situation. > > > > Could you please test it with your setup and report whether this > > allows you to boot a VHE guest? You will need to patch the guest. > > > > Note that this still won't let you recursively virtualise EL2 (the HW > > can do it, but KVM in the guest doesn't know it), but that's better > > than nothing. > > Thanks Marc, > I tried it in my Guest, on top of 6.17.0. It seems to be working. > > > Without HAS_EL2_E2H0: > CPU features: detected: Virtualization Host Extensions > CPU: All CPU(s) started at EL2 > kvm [1]: VHE mode initialized successfully > > > With HAS_EL2_E2H0: > CPU: All CPU(s) started at EL2 > kvm [1]: Hyp nVHE mode initialized successfully > > In both cases SVE is also initialized properly. Great. Would you mind replying to the patch with a Tested-by: tag? Thanks, M. -- Without deviation from the norm, progress is not possible.