From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id B5D7E288538 for ; Tue, 29 Jul 2025 09:58:00 +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=1753783082; cv=none; b=nnyZitenIv0FtHr1aQWaIHe05WV0+K1a1KC51yLMY/vARZC7CCZCiRv6qaKsUOB/b6TdnTgjJIsGcggvQOYbXXoq45z3vSBj//obyNMX1IyFJmmVPl1y9+Mhv7IqUMmKp+vfo1vTdrvaVYpSgQ10E9Oc82Eg9td7B6qiY8Si9pk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753783082; c=relaxed/simple; bh=Bfz3nltGgSOdWEwaV5RL1qE6Mh1cTW89qZ+FnPkbCSs=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=n173tavgUQcpXcP47lNDyc0rQsdzdeVfGvJXDjf2ff9A7xeq+qXMBl/RbUzccsR7X8+8nRD1FXUgym1tee5vg23fSYSq4wLvg9ib+SAIKhBO4DyAmQQS0SclkWkBGOB+qxrtSXwqaEtL/3gmOUI4aB6d2ReCqMJXIPIFeXf+ojE= 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 617592444; Tue, 29 Jul 2025 02:57:51 -0700 (PDT) Received: from donnerap.arm.com (donnerap.manchester.arm.com [10.32.101.27]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 27C523F673; Tue, 29 Jul 2025 02:57:58 -0700 (PDT) From: Andre Przywara To: Will Deacon , Julien Thierry , Marc Zyngier Cc: kvm@vger.kernel.org, kvmarm@lists.linux.dev, Alexandru Elisei Subject: [PATCH kvmtool v3 5/6] arm64: add FEAT_E2H0 support Date: Tue, 29 Jul 2025 10:57:44 +0100 Message-Id: <20250729095745.3148294-6-andre.przywara@arm.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20250729095745.3148294-1-andre.przywara@arm.com> References: <20250729095745.3148294-1-andre.przywara@arm.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Marc Zyngier The --nested option allows a guest to boot at EL2 without FEAT_E2H0 (i.e. mandating VHE support). While this is great for "modern" operating systems and hypervisors, a few legacy guests are stuck in a distant past. To support those, add the --e2h0 command line option, that exposes FEAT_E2H0 to the guest, at the expense of a number of other features, such as FEAT_NV2. This is conditioned on the host itself supporting FEAT_E2H0. Signed-off-by: Marc Zyngier Signed-off-by: Andre Przywara --- arm64/include/kvm/kvm-config-arch.h | 5 ++++- arm64/kvm-cpu.c | 5 +++++ 2 files changed, 9 insertions(+), 1 deletion(-) diff --git a/arm64/include/kvm/kvm-config-arch.h b/arm64/include/kvm/kvm-config-arch.h index 44c43367b..73bf4211a 100644 --- a/arm64/include/kvm/kvm-config-arch.h +++ b/arm64/include/kvm/kvm-config-arch.h @@ -11,6 +11,7 @@ struct kvm_config_arch { bool has_pmuv3; bool mte_disabled; bool nested_virt; + bool e2h0; u64 kaslr_seed; enum irqchip_type irqchip; u64 fw_addr; @@ -63,6 +64,8 @@ int sve_vl_parser(const struct option *opt, const char *arg, int unset); OPT_U64('\0', "counter-offset", &(cfg)->counter_offset, \ "Specify the counter offset, defaulting to 0"), \ OPT_BOOLEAN('\0', "nested", &(cfg)->nested_virt, \ - "Start VCPUs in EL2 (for nested virt)"), + "Start VCPUs in EL2 (for nested virt)"), \ + OPT_BOOLEAN('\0', "e2h0", &(cfg)->e2h0, \ + "Create guest without VHE support"), #endif /* ARM_COMMON__KVM_CONFIG_ARCH_H */ diff --git a/arm64/kvm-cpu.c b/arm64/kvm-cpu.c index 42dc11dad..5e4f3a7dd 100644 --- a/arm64/kvm-cpu.c +++ b/arm64/kvm-cpu.c @@ -76,6 +76,11 @@ static void kvm_cpu__select_features(struct kvm *kvm, struct kvm_vcpu_init *init if (!kvm__supports_extension(kvm, KVM_CAP_ARM_EL2)) die("EL2 (nested virt) is not supported"); init->features[0] |= 1UL << KVM_ARM_VCPU_HAS_EL2; + if (kvm->cfg.arch.e2h0) { + if (!kvm__supports_extension(kvm, KVM_CAP_ARM_EL2_E2H0)) + die("FEAT_E2H0 is not supported"); + init->features[0] |= 1UL << KVM_ARM_VCPU_HAS_EL2_E2H0; + } } } -- 2.25.1