From nobody Mon Apr 6 18:28:59 2026 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 9C06F2D23A5; Wed, 18 Mar 2026 15:54:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773849302; cv=none; b=eQDUH5nInDn6hwuGabdsmoXvDwCQ9fsVXSrxR0m86WdcWiX0vlH190XhyoNTwpt2fwWHzYw6CY3OOuKe5+jSW66XkixX7SJmYNfCY7r6K/a+vPpGLQYPlTHlGYHtJiO/L7qLvMoTJwZopx/l0A8FJ63XIlEkuPU8zihdvpsgbro= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773849302; c=relaxed/simple; bh=/ioKEmdEMjgsjCaeDYeWkBQVD3DtELc+u+if79p20oU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=rsvsCCPDuvDGL/SV+cCXdWXGqlEn+utLPqoBp8ix8+prsDl64raffJb8QU/4a075k+bZAaWZXmuV70Ks9Rl1En2gqPGojBAlXr3B1mQI468LCSmnUtelYjGV3wdgVu+lugvSmRW/GZf+WF4zUXEggZEDEGAkrLO0oW+p5ZosJUQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 4514F201B; Wed, 18 Mar 2026 08:54:52 -0700 (PDT) Received: from e122027.arm.com (unknown [10.57.61.122]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id DB9CF3F73B; Wed, 18 Mar 2026 08:54:54 -0700 (PDT) From: Steven Price To: kvm@vger.kernel.org, kvmarm@lists.linux.dev Cc: Steven Price , Catalin Marinas , Marc Zyngier , Will Deacon , James Morse , Oliver Upton , Suzuki K Poulose , Zenghui Yu , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Joey Gouly , Alexandru Elisei , Christoffer Dall , Fuad Tabba , linux-coco@lists.linux.dev, Ganapatrao Kulkarni , Gavin Shan , Shanker Donthineni , Alper Gun , "Aneesh Kumar K . V" , Emi Kisanuki , Vishal Annapurve Subject: [PATCH v13 09/48] arm64: RMI: Check for LPA2 support Date: Wed, 18 Mar 2026 15:53:33 +0000 Message-ID: <20260318155413.793430-10-steven.price@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260318155413.793430-1-steven.price@arm.com> References: <20260318155413.793430-1-steven.price@arm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" If KVM has enabled LPA2 support then check that the RMM also supports it. If there is a mismatch then disable support for realm guests as the VMM may attempt to create a guest which is incompatible with the RMM. Signed-off-by: Steven Price --- New patch for v13 --- arch/arm64/kvm/rmi.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/arch/arm64/kvm/rmi.c b/arch/arm64/kvm/rmi.c index 482dc542451a..9590dff9a2c1 100644 --- a/arch/arm64/kvm/rmi.c +++ b/arch/arm64/kvm/rmi.c @@ -5,12 +5,18 @@ =20 #include =20 +#include #include #include =20 static unsigned long rmm_feat_reg0; static unsigned long rmm_feat_reg1; =20 +static bool rmi_has_feature(unsigned long feature) +{ + return !!u64_get_bits(rmm_feat_reg0, feature); +} + static int rmi_check_version(void) { struct arm_smccc_res res; @@ -89,6 +95,16 @@ static int rmi_configure(void) return 0; } =20 +static int rmm_check_features(void) +{ + if (kvm_lpa2_is_enabled() && !rmi_has_feature(RMI_FEATURE_REGISTER_0_LPA2= )) { + kvm_err("RMM doesn't support LPA2"); + return -ENXIO; + } + + return 0; +} + void kvm_init_rmi(void) { /* Continue without realm support if we can't agree on a version */ @@ -100,6 +116,8 @@ void kvm_init_rmi(void) if (WARN_ON(rmi_features(1, &rmm_feat_reg1))) return; =20 + if (rmm_check_features()) + return; if (rmi_configure()) return; =20 --=20 2.43.0