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 24B5819D06E; Tue, 1 Oct 2024 14:28:53 +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=1727792934; cv=none; b=ezJlJoT0+AGNMxuafPWHySLexjfac4B5UglTRkRcAtw0f/R+0pmSwbwTPEnv8jUV+M9Um/tTUlLsODnDWLihTzIk/xTptcJoeWB57XyjthlHy6h5QCRf/Kxgaqd+4W2Di+w20vupXMxB5OMEzGg1zTzLPqXbrUqcJzD9OOdjqt0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727792934; c=relaxed/simple; bh=BfXFLlNKiq7zB8ABiOruQbTuJYh7ru1h5GVjgRxtnu4=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version:Content-Type; b=DuUzF0afVADdzmye6NF/i2LiVFsMPCJGbac1xyHvyn3KD8RQkuQsWUgAnTceTbi9V5wdPt5QqFWL+BZM/g+3da1VCI9SZZGBccCEzAmvunCHVwqTk8AT6cyGEqk98Re7FzE/bqitk2z9iX4vXSLpuffDpIBaIFIDcXRMwIAnYyk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=awZQFoKo; 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="awZQFoKo" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B174FC4CEC7; Tue, 1 Oct 2024 14:28:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1727792933; bh=BfXFLlNKiq7zB8ABiOruQbTuJYh7ru1h5GVjgRxtnu4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=awZQFoKoX2m3aot9qn/OsvWfaUQ5EGw8IqS8Y/Qj+W7aBnfd8lq+QvE6m+H9SG0L7 sFwIPsTzVHk8qC1ye78D8rPHJ84JHROUq7H+n3qzdXa3znnewH58S15yZJzJyOrAKz JTh9Ct8PQKZVWQvn316Km+WxzxoXunuA8FAO8kl8uiJCNSqejBjJLG4tmrJrlP+Er3 Q8yOuUT1nwz/E/LHIvb5m+1/2XMuiwj2CsHbid+4IJA2z3MP2YPqmpTM8SyxCe4YWo 86QVrAiE2y9TNDajrEmJUoW09BXtf/x+N2tULrd+57twVDUAQ4GT39fE5NKQWVu69b shFOLuFQ2sVDQ== Received: from sofa.misterjones.org ([185.219.108.64] helo=valley-girl.lan) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1svdru-00GmGt-GR; Tue, 01 Oct 2024 15:28:51 +0100 From: Marc Zyngier To: Oliver Upton , James Morse , Suzuki K Poulose , Catalin Marinas , Will Deacon , Fuad Tabba , Mark Brown Cc: Dave Martin , linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] KVM: arm64: Constrain the host to the maximum shared SVE VL with pKVM Date: Tue, 1 Oct 2024 15:28:40 +0100 Message-Id: <172779288243.1647258.11526223607121965745.b4-ty@kernel.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240912-kvm-arm64-limit-guest-vl-v2-1-dd2c29cb2ac9@kernel.org> References: <20240912-kvm-arm64-limit-guest-vl-v2-1-dd2c29cb2ac9@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: oliver.upton@linux.dev, james.morse@arm.com, suzuki.poulose@arm.com, catalin.marinas@arm.com, will@kernel.org, tabba@google.com, broonie@kernel.org, Dave.Martin@arm.com, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-kernel@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, 12 Sep 2024 12:39:35 +0100, Mark Brown wrote: > When pKVM saves and restores the host floating point state on a SVE system > it programs the vector length in ZCR_EL2.LEN to be whatever the maximum VL > for the PE is but uses a buffer allocated with kvm_host_sve_max_vl, the > maximum VL shared by all PEs in the system. This means that if we run on a > system where the maximum VLs are not consistent we will overflow the buffer > on PEs which support larger VLs. > > [...] Applied to fixes, thanks! [1/1] KVM: arm64: Constrain the host to the maximum shared SVE VL with pKVM commit: a9f41588a902f386b48f021f56a4c14735cd9371 Cheers, M. -- Without deviation from the norm, progress is not possible.