From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 2769D4EE872; Thu, 3 Sep 2026 16:50:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788454227; cv=none; b=BcouRvB1EMUZMnmkj70+b9uy5tKcu5vyXVUEGRXuZ1FKVmlxymuNXNnU2fDXTMASF04Oj7um1mr+KhBOko3THNk2vrw88I/IKA05g/ywdanB0MtenYfLDOK4zNYap/zgYJpT2QAq308dq+EMlKqnjKvCaFV+s+5p3Q3asI21jEY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788454227; c=relaxed/simple; bh=F4iZVS6D2gd2z15r43lWksE4Vt4lg5qGl3HF4LkTc8o=; h=From:Subject:To:Cc:In-Reply-To:References:Content-Type:Date: Message-Id; b=XfJ1xBETZsvOznoFJXLAXzrkdWzJCfsXSfmFLHvSz/QyDSkLOyoRssC88o+qxaA8R2ED95lZKWj2DiFVv7PqT9OHEpiSb1ORao75BTVk260wCA+Jkk1Zy4/pmA0DtChepNqFqKrTgK1EPn8GUAUhj1Uehz0/gA8wFweLg814Wz0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=RoNxt153; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="RoNxt153" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8290F1F000E9; Thu, 3 Sep 2026 16:50:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788454225; bh=RucA1tkaxJH9WuoWLyiQd9FcfFTxNNoXlZn61Ec9uAU=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=RoNxt153/88VSWl4TlG7qdU4zZaC3SLAJEtFsYBww69ZI9yMgyhrZUrNXKwbYdaaf BNfmEmH8u0GsGyRlC68WKk8/m2aMh9vTBED86FaRCZgL2RkIuLojlsOtBzx8XEwuc9 BacOQE8gB3gV0qP670RvHMQ3FPdiYBlltskU/DF+AjdTVEZhPjA9+XIYxowycHs9q6 JkuH9FPLHjpv+72ViswQJLHq/iXYi7D7PBSoRsC564tB5DjtJkxwciy4AEtHcDJf8r AIVWaAZV1W317zsUNn09hA9JqBqtvVA+lo4rJfWwJtWt82i3VvJ5NaGYIEj5klhHiS UOet/Y+EZLcew== From: sashiko-bot@kernel.org Subject: Re: [RFC PATCH v7 22/28] arm64: errata: Disable SPE in KVM Reply-To: sashiko-reviews@lists.linux.dev To: "Alexandru Elisei" Cc: kvmarm@lists.linux.dev, linux-perf-users@vger.kernel.org, "Oliver Upton" , "Marc Zyngier" In-Reply-To: <20260903160623.315525-23-alexandru.elisei@arm.com> References: <20260903160623.315525-1-alexandru.elisei@arm.com> <20260903160623.315525-23-alexandru.elisei@arm.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Thu, 03 Sep 2026 16:50:25 +0000 Message-Id: <20260903165025.8290F1F000E9@smtp.kernel.org> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: > When stage 1 is enabled and buffer virtual address VA is mapped as > read-only, and hardware dirty bit management is disabled at stage 1 and > stage 2, if stage 2 is enabled, SPE might write to address VA instead of > generating a fault. >=20 > This doesn't affect the SPE driver when running on baremetal, since the > memory is mapped at stage 1 with write permissions. >=20 > KVM does not use hardware dirty bit management and this erratum allows a > guest to write to read-only memory as long as that address is mapped at > stage 2. >=20 > Since KVM allows userspace to use SPE on heterogenous systems, where there > might be different SPE instances, tie the workaround to a particular SPE > instance and do not allow userspace to use that instance when it is > [ ... ] > https://support.arm.com/documentation/SDEN-2055130/18-0 > * ARM Cortex-X4 (MP161), SDEN v13, erratum 3022725 > https://support.arm.com/documentation/109148/13-0 >=20 > Signed-off-by: Alexandru Elisei Sashiko has reviewed this patch and found no issues. It looks great! --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20260903160623.3155= 25-1-alexandru.elisei@arm.com?part=3D22