From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f53.google.com (mail-wm1-f53.google.com [209.85.128.53]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D311A28934F for ; Thu, 29 Jan 2026 16:39:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.53 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769704782; cv=none; b=dM1qLQCetJLCpOjEkBpPpfKrYRIZt135fpQIISIsfbViJXmKaVnTIJGnaPSLGJXMv4TKCcsOsyWZg91svnqKj8mHpRQG8lHRx7+k3GdFXtcD6QkToiI6inn3Rkh7VdrM+K+dqadxGGq3kv2kGjKMlj1Mtvm3dqZbA4kzAAIRH4I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769704782; c=relaxed/simple; bh=B/VHJ92gUrkCQ08cznGlZPMEjHU0vpIWoo2Ylnqd+/4=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=U8xIM68AF9uk+OoT5PLgtQVdHFRZAcwFGr4a5V2qGOnFQ2EWsc//zMG4d9UHeLWf3iT9pohI2TiteKpI68hkxURdXRGtZ2FR2BVRGsUALEVGR2P2D12dRRdpmtNd0NWUqxCw8cDhhVNLz9Wb1wUZ2JEM/NmLyLhZbOujgSdtRWk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linaro.org; spf=pass smtp.mailfrom=linaro.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b=ePOWaA4F; arc=none smtp.client-ip=209.85.128.53 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linaro.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linaro.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="ePOWaA4F" Received: by mail-wm1-f53.google.com with SMTP id 5b1f17b1804b1-47fedb7c68dso12486875e9.2 for ; Thu, 29 Jan 2026 08:39:36 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1769704775; x=1770309575; darn=lists.linux.dev; h=content-transfer-encoding:mime-version:user-agent:message-id:date :references:in-reply-to:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=twFvpc0i3TryasBkxK98iJJPXOi65K0zMxpJo29cyB0=; b=ePOWaA4FkEkp5GhKrXdK3RRZ1GAYEmtucB3PbRLuv7VhfDVECRsHipbS9HQ8xKbpfF /IIeMiBeEgLeJE1uB2CPIW9ey65NyKQ56wpfeF0gOlFddH9uwckmqYat7ZSnvsSp60hA tabV2yYTU6c4FJbFQHQDEj/2mHOUl3XNLsAAbAccUDm4qsSYjgWNRGj1VEA5cIl+U564 cab0QHEyTA28miRh+sZqyp71rv1+Ts3zBdr2yKgj3LDXi/wqtqOgNANmQvFuzzPD5AVA XZowW90LtnHieN0sfGc22teM5kQg7wYCasps86M7XIIU8OPFY/MSsPt/h4dDgU4hq4Q4 /tQw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1769704775; x=1770309575; h=content-transfer-encoding:mime-version:user-agent:message-id:date :references:in-reply-to:subject:cc:to:from:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=twFvpc0i3TryasBkxK98iJJPXOi65K0zMxpJo29cyB0=; b=dimnQshNS29LGhqn9mIeVX7oSy6diGpKFt7H6sWsz61gCivCQn1n0h99rHbaD2xk7b MCvI+V0vfjm9EuhOYXG+mWnGdPuJsHAmiyh1l8E3ByfBeLK8Hwcggk9jJaqVkgpXGboM wcGn4HVd7ad2NyMeRDns2xl4ZKiUQcIt4pMWqtQHREDO2b7vvKh3JcvEu2hzCR92+PWX ToI1s7erSEdpKvYShp07ZA7rVvVYz39bLWrmrtlpKGhfRu6kkYbNzzPui5HzI4UfEB4p 9Mj2eDP2dA5v0cM3q1ClpAEf99J/oI0ASyJe2ZMQgNKNTtSpjqFF/Pwxf8gHpIe132z9 /gMA== X-Forwarded-Encrypted: i=1; AJvYcCW5Bo+XvAs9BtG3OC+7zkDQeD8Xk8hGdStCRbxDNkz24BM9xMxBtRYOgB3ZDKF9zEgAroh/7oE=@lists.linux.dev X-Gm-Message-State: AOJu0Yxv6wmdHRhQI/Aizo5dkFSId/jf4K7JSussh0SrFZHLEfDXJxm9 vD08D+pXBuyRT+OeiYRD3IFqWXt1Y5tMnUVETybKU+OiLPl/ejp5CbcvXy/v09W0MP8= X-Gm-Gg: AZuq6aKh+EH8qqoCRbDWtfuYJV1rrOlN+7a3ILcGZWx3sM5ySMBu1tiEHNej7QUGreD KIOSos3lxL55NYeXRp9re5tLFW/m7y3H7Ij2me+2Va6/IRPAMq3sbpG58IPBpe8U5XlCYUxT+xy uuGmqUn5HrpL+rD+3YMsYuPh/yQP7H5+u+CT4MbTIpidpnRav0fYjAp9266MPpJ8FVTsJz+7KLI LZc4MyOroDaxz+1lIfpbJE0t4vuOqydWXqQTHUuOO1plvHxx0iym9h4Gwg7tKscFuDmrHhuNESo bnq6Qg1j3QDPaR5VC4ng0Qpg3Ngej7le31jH/uN59/rn594IUCItE2EPLwS9xNYqbE1kXGufR93 zF93QHIb9yCsLY0gEfZK5Z5YgvSaH3ZBrB5H9lLX8CFWqJ/IWOtPn0Qte8LGxvYzVoxzxsZKvRn 0PNWUZIVDFuHQ= X-Received: by 2002:a05:6000:184e:b0:432:5b81:48b with SMTP id ffacd0b85a97d-435f3ad5c6dmr249217f8f.61.1769704775134; Thu, 29 Jan 2026 08:39:35 -0800 (PST) Received: from draig.lan ([185.124.0.126]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-435e131cfd4sm14914838f8f.25.2026.01.29.08.39.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 29 Jan 2026 08:39:34 -0800 (PST) Received: from draig (localhost [IPv6:::1]) by draig.lan (Postfix) with ESMTP id A5D885F878; Thu, 29 Jan 2026 16:39:33 +0000 (GMT) From: =?utf-8?Q?Alex_Benn=C3=A9e?= To: Mark Brown Cc: Marc Zyngier , Joey Gouly , Catalin Marinas , Suzuki K Poulose , Will Deacon , Paolo Bonzini , Jonathan Corbet , Shuah Khan , Oliver Upton , Dave Martin , Fuad Tabba , Mark Rutland , Ben Horgan , linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, Peter Maydell , Eric Auger Subject: Re: [PATCH v9 04/30] arm64/fpsimd: Check enable bit for FA64 when saving EFI state In-Reply-To: <20251223-kvm-arm64-sme-v9-4-8be3867cb883@kernel.org> (Mark Brown's message of "Tue, 23 Dec 2025 01:20:58 +0000") References: <20251223-kvm-arm64-sme-v9-0-8be3867cb883@kernel.org> <20251223-kvm-arm64-sme-v9-4-8be3867cb883@kernel.org> Date: Thu, 29 Jan 2026 16:39:33 +0000 Message-ID: <87343o8jay.fsf@draig.linaro.org> User-Agent: Gnus/5.13 (Gnus v5.13) Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Mark Brown writes: > Currently when deciding if we need to save FFR when in streaming mode pri= or > to EFI calls we check if FA64 is supported by the system. Since KVM guest > support will mean that FA64 might be enabled and disabled at runtime swit= ch > to checking if traps for FA64 are enabled in SMCR_EL1 instead. > > Signed-off-by: Mark Brown > --- > arch/arm64/kernel/fpsimd.c | 9 +++++++-- > 1 file changed, 7 insertions(+), 2 deletions(-) > > diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c > index 887fce177c92..f4e8cee00198 100644 > --- a/arch/arm64/kernel/fpsimd.c > +++ b/arch/arm64/kernel/fpsimd.c > @@ -1948,6 +1948,11 @@ static bool efi_sm_state; > * either doing something wrong or you need to propose some refactoring. > */ >=20=20 > +static bool fa64_enabled(void) > +{ > + return read_sysreg_s(SYS_SMCR_EL1) & SMCR_ELx_FA64; > +} > + > /* > * __efi_fpsimd_begin(): prepare FPSIMD for making an EFI runtime servic= es call > */ > @@ -1980,7 +1985,7 @@ void __efi_fpsimd_begin(void) > * Unless we have FA64 FFR does not > * exist in streaming mode. > */ > - if (!system_supports_fa64()) > + if (!fa64_enabled()) > ffr =3D !(svcr & SVCR_SM_MASK); > } >=20=20 > @@ -2028,7 +2033,7 @@ void __efi_fpsimd_end(void) > * Unless we have FA64 FFR does not > * exist in streaming mode. > */ > - if (!system_supports_fa64()) > + if (!fa64_enabled()) > ffr =3D false; > } > } This is conflicting with the now merged 63de2b3859ba1 (arm64/efi: Remove unneeded SVE/SME fallback preserve/store handling) so I think this patch can now be dropped? --=20 Alex Benn=C3=A9e Virtualisation Tech Lead @ Linaro