From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=95.215.58.83 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792914710; b=4d5VnNfGIzb+/1RWZHWZHQ5kDig/Uq3yBee2XVsavIblh4zwEP3fdRf7+hyCMUGfzSHA f7Q94pLfrvOcCiG5MsILwWce2NheAJGCeoWXF7nqPdPvTm3kfFVPgRgldIu2cLOiIJN8s pc5uJZf5svrAsN+C8NAEiFVmAoCdIlBPq/O7mcJtZEH2j+kcAP4qL6WTzNdRcFm9Zm/lo yXicZvMA8OXnPi6aW9LHwr9ZtHzBCT843yXmw58h+EtAfB/rGQKOEbP5Rg9kcmYeDZ7nm jnvFbytBjDmaC7QYnXiFUDx3+xfZzJ0BF+UK7lIelQFzTE+x84GuuaMZKamqqjW3W9Q== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792914710; h=DMARC-Filter:X-Envelope-To:DKIM-Signature:X-Envelope-To:Received: X-Mizu-Trace-ID:X-Migadu-Flow:From:To:Cc:Subject:Date:Message-ID: X-Mailer:In-Reply-To:References:MIME-Version: Content-Transfer-Encoding; bh=BKCIoewPxqJjcEiMn9aSQhwGTJS5ZRgwusOumNV0ZUQ=; b=BFWCrkrXmX0/gQB7qTl+bDiQ6JzRXUWHaDM+qMTRqrpNK74lf3MzuUWCrTsvIHbjheOh cKggHGpW7S1G73njJ/iJiUepKA6JHfsiTSC4Y8aGUCG8jgHJ1uoFclhA2JnEfxB32Xpci xAq8tkqwLSIqXL97M1/xcYGyQgvdWGHgPexWNRNm4Y4HL1KSj9JQpQFYGUd4lItktd/XZ LCNOLsX9uh7WaMNA49XurdfVC7RVFaY3WN4x6cu6We0n/CdZTbBfX/Mofrmm7uztArBRM +Del74gIegqpAJ1hu3eg4TJDvC3W8o11dzZOUUBvG+CIezjcGr60QSFoPyjDTMaDr7w== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=HdJQUu1a; arc=none smtp.remote-ip=95.215.58.83 Received: from mta1.migadu.com (out-83.mta1.migadu.com [95.215.58.83]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E092D606A31A for ; Sun, 25 Oct 2026 07:51:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org E092D606A31A Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=HdJQUu1a X-Envelope-To: kvm@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=PFBAXwuqQFvijjX3+VrafA0FdNMSxN6wY89RZNPerd8=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1792914707; v=1; x=1793519507; b=HdJQUu1ayqge7qfrxwLdd4FELHnZf0oyAY/CGV7uKs21K5SrdMGw7oHi8l7mi/uI58ddAeMp o6vL1PVURof9cmd5g8Bv1tNTluivYqfm3Cn7jO7ATVFwM9qPpBydBp1hNgwkgxnVV0B79jNS9W3 UE8s+melIna9HJxYBacDbXbE= X-Envelope-To: kvm@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id b9760d0147542ea5; Sun, 25 Oct 2026 07:51:47 +0000 X-Mizu-Trace-ID: b9760d0147542ea5 X-Migadu-Flow: FLOW_OUT From: Fuad Tabba To: Marc Zyngier , Oliver Upton , kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org Cc: Catalin Marinas , Will Deacon , Joey Gouly , Suzuki K Poulose , Zenghui Yu , Steffen Eiden , Mark Rutland , Yicong Yang , Zhou Wang , Arnd Bergmann , Fuad Tabba , kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 1/5] arm64: Add override for ID_AA64ISAR1_EL1.LS64 Date: Sun, 25 Oct 2026 07:51:34 +0000 Message-ID: <20261025075138.2919734-2-fuad.tabba@linux.dev> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20261025075138.2919734-1-fuad.tabba@linux.dev> References: <20261025075138.2919734-1-fuad.tabba@linux.dev> X-Mailing-List: kvm@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Accesses to ACCDATA_EL1, which FEAT_LS64_ACCDATA adds, trap to EL3 unless firmware sets SCR_EL3.ADEn. Once KVM context-switches the register for its guests, a host whose firmware leaves the bit clear can't run them. Add an override for ID_AA64ISAR1_EL1.LS64, with an arm64.nols64 alias, so that the feature can be disabled on such a host and for its guests. id_aa64isar1.ls64=2 disables only FEAT_LS64_ACCDATA and above. Cc: stable@vger.kernel.org Signed-off-by: Fuad Tabba --- Documentation/admin-guide/kernel-parameters.txt | 3 +++ arch/arm64/kernel/pi/idreg-override.c | 2 ++ 2 files changed, 5 insertions(+) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 33cd30996e47e..ef690cf6c3664 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -571,6 +571,9 @@ Kernel parameters arm64.nohaft [ARM64] Unconditionally disable Hardware managed Access Flag for Table descriptors support + arm64.nols64 [ARM64] Unconditionally disable 64-byte Load/Store + instructions support + arm64.nomops [ARM64] Unconditionally disable Memory Copy and Memory Set instructions support diff --git a/arch/arm64/kernel/pi/idreg-override.c b/arch/arm64/kernel/pi/idreg-override.c index 274bc72ba98d0..0c7f293779c1f 100644 --- a/arch/arm64/kernel/pi/idreg-override.c +++ b/arch/arm64/kernel/pi/idreg-override.c @@ -174,6 +174,7 @@ static const struct ftr_set_desc isar1 __prel64_initconst = { .name = "id_aa64isar1", .override = &id_aa64isar1_override, .fields = { + FIELD("ls64", ID_AA64ISAR1_EL1_LS64_SHIFT, NULL), FIELD("gpi", ID_AA64ISAR1_EL1_GPI_SHIFT, NULL), FIELD("gpa", ID_AA64ISAR1_EL1_GPA_SHIFT, NULL), FIELD("api", ID_AA64ISAR1_EL1_API_SHIFT, NULL), @@ -253,6 +254,7 @@ static const struct { "id_aa64isar1.gpi=0 id_aa64isar1.gpa=0 " "id_aa64isar1.api=0 id_aa64isar1.apa=0 " "id_aa64isar2.gpa3=0 id_aa64isar2.apa3=0" }, + { "arm64.nols64", "id_aa64isar1.ls64=0" }, { "arm64.nomops", "id_aa64isar2.mops=0" }, { "arm64.nomte", "id_aa64pfr1.mte=0" }, { "nokaslr", "arm64_sw.nokaslr=1" }, -- 2.47.3