From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 927AF606A31D for ; Sun, 25 Oct 2026 07:52:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=lists.infradead.org header.i=@lists.infradead.org header.a=rsa-sha256 header.s=bombadil.20210309 header.b=taZh8zv4; dkim=pass (1024-bit key, unprotected) header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=HdJQUu1a DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Unsubscribe-Post: List-Owner; bh=BKCIoewPxqJjcEiMn9aSQhwGTJS5ZRgwusOumNV0ZUQ=; b=taZh8zv4GklVXs WKRVQgOHXOJTL7gUFcEYVSELh7nugNxTxyhc1Su63IcwOK3hBr8L2654R9rCfy9yz9WewWU0hqF2G 9LiAo/pg2kHzWq9RdFXJS+2GCAVCOC7JTfuIQ2e2KjJEvbFa5+WSzkBNoYnlPnNkQNywSK1KZhTWb 0l2GWok/cd8U4rzTjItTgf7gjlTWZ0b5fOvv/v+DfYQ9sSlfevXye91OKnxzGRBplWMBIW1wHi/XK vJjWB0ZCetcvlVydgC5FMaR/E/0+w9qIzYzOm1XrIMXgcpVAha9PJMoesxYvCN+Zf5WS4J7UHm33u Q0O0EvK20n+MVGT2Dqgg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xKt1J-00000000qt0-01v4; Sun, 25 Oct 2026 07:51:57 +0000 Received: from out-79.mta1.migadu.com ([95.215.58.79] helo=mta1.migadu.com) by bombadil.infradead.org with esmtps (Exim 4.100.1 #2 (Red Hat Linux)) id 1xKt1B-00000000qrP-47kA for linux-arm-kernel@lists.infradead.org; Sun, 25 Oct 2026 07:51:51 +0000 X-Envelope-To: linux-arm-kernel@lists.infradead.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: linux-arm-kernel@lists.infradead.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-Archived-By: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20261025_005150_165466_29C3C1B1 X-CRM114-Status: GOOD ( 11.06 ) X-Spam-Score: -2.8 (--) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" X-Spam-Status: No, score=-19.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 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