From patchwork Thu Feb 9 17:58:03 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marc Zyngier X-Patchwork-Id: 13134925 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B21E9C64EC4 for ; Thu, 9 Feb 2023 17:58:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230140AbjBIR64 (ORCPT ); Thu, 9 Feb 2023 12:58:56 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47036 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229834AbjBIR6w (ORCPT ); Thu, 9 Feb 2023 12:58:52 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 90D3F60BB4 for ; Thu, 9 Feb 2023 09:58:50 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 44AE8B82282 for ; Thu, 9 Feb 2023 17:58:49 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D6A63C4339B; Thu, 9 Feb 2023 17:58:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1675965527; bh=RZMIS1gWp+105YhVM/qcEDBwXsDYL2EyKON2lk0Ivkw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=gPACkFXQwf3Bw5W70rsHpqpRc26SlO3qX9vN2zv/bz4GZhAGxUr/dIU2o6BBDeIna SHv7PDtIH75wvkVsrnvFT3zL+0y36zaQYCp+DRx39WJAY4rghE9dOUGBlUtji+DNys p3Jc+Qof3uHGUcps/Rfb/ET5uRRvs+Kzri7Kqk/MtRoIuU1MOFztiW6fKRdMWrI4As aG2ZmhAlqQpNPwWYi/pVBl1MJvvQDlNXL8p1xeUP4ASeVRzL0+b0eilj3rdRWZAzQU jg+d83uVIGgC39RLHxM2tqdAfDZz45bY33UkZz1WC55Py93n5ZEGiBqRl69NWyuZiD vtfyLqOgIlEzQ== Received: from sofa.misterjones.org ([185.219.108.64] helo=valley-girl.lan) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1pQBC1-0093r7-Q3; Thu, 09 Feb 2023 17:58:45 +0000 From: Marc Zyngier To: kvmarm@lists.linux.dev, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: Alexandru Elisei , Andre Przywara , Catalin Marinas , Christoffer Dall , Ganapatrao Kulkarni , Russell King , James Morse , Suzuki K Poulose , Oliver Upton , Zenghui Yu Subject: [PATCH 01/18] arm64: Add ARM64_HAS_NESTED_VIRT cpufeature Date: Thu, 9 Feb 2023 17:58:03 +0000 Message-Id: <20230209175820.1939006-2-maz@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230209175820.1939006-1-maz@kernel.org> References: <20230209175820.1939006-1-maz@kernel.org> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: kvmarm@lists.linux.dev, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, alexandru.elisei@arm.com, andre.przywara@arm.com, catalin.marinas@arm.com, christoffer.dall@arm.com, gankulkarni@os.amperecomputing.com, rmk+kernel@armlinux.org.uk, james.morse@arm.com, suzuki.poulose@arm.com, oliver.upton@linux.dev, yuzenghui@huawei.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Jintack Lim Add a new ARM64_HAS_NESTED_VIRT feature to indicate that the CPU has the ARMv8.3 nested virtualization capability, together with the 'kvm-arm.mode=nested' command line option. This will be used to support nested virtualization in KVM. Reviewed-by: Russell King (Oracle) Acked-by: Catalin Marinas Signed-off-by: Jintack Lim Signed-off-by: Andre Przywara Signed-off-by: Christoffer Dall [maz: moved the command-line option to kvm-arm.mode] Signed-off-by: Marc Zyngier --- .../admin-guide/kernel-parameters.txt | 7 +++++- arch/arm64/include/asm/kvm_host.h | 5 ++++ arch/arm64/kernel/cpufeature.c | 25 +++++++++++++++++++ arch/arm64/kvm/arm.c | 5 ++++ arch/arm64/tools/cpucaps | 1 + 5 files changed, 42 insertions(+), 1 deletion(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 6cfa6e3996cf..b7b0704e360e 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -2553,9 +2553,14 @@ protected: nVHE-based mode with support for guests whose state is kept private from the host. + nested: VHE-based mode with support for nested + virtualization. Requires at least ARMv8.3 + hardware. + Defaults to VHE/nVHE based on hardware support. Setting mode to "protected" will disable kexec and hibernation - for the host. + for the host. "nested" is experimental and should be + used with extreme caution. kvm-arm.vgic_v3_group0_trap= [KVM,ARM] Trap guest accesses to GICv3 group-0 diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 35a159d131b5..8919e971abdf 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -60,9 +60,14 @@ enum kvm_mode { KVM_MODE_DEFAULT, KVM_MODE_PROTECTED, + KVM_MODE_NV, KVM_MODE_NONE, }; +#ifdef CONFIG_KVM enum kvm_mode kvm_get_mode(void); +#else +static inline enum kvm_mode kvm_get_mode(void) { return KVM_MODE_NONE; }; +#endif DECLARE_STATIC_KEY_FALSE(userspace_irqchip_in_use); diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index a77315b338e6..3fc14ee86239 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -1956,6 +1956,20 @@ static void cpu_copy_el2regs(const struct arm64_cpu_capabilities *__unused) write_sysreg(read_sysreg(tpidr_el1), tpidr_el2); } +static bool has_nested_virt_support(const struct arm64_cpu_capabilities *cap, + int scope) +{ + if (kvm_get_mode() != KVM_MODE_NV) + return false; + + if (!has_cpuid_feature(cap, scope)) { + pr_warn("unavailable: %s\n", cap->desc); + return false; + } + + return true; +} + #ifdef CONFIG_ARM64_PAN static void cpu_enable_pan(const struct arm64_cpu_capabilities *__unused) { @@ -2215,6 +2229,17 @@ static const struct arm64_cpu_capabilities arm64_features[] = { .matches = runs_at_el2, .cpu_enable = cpu_copy_el2regs, }, + { + .desc = "Nested Virtualization Support", + .capability = ARM64_HAS_NESTED_VIRT, + .type = ARM64_CPUCAP_SYSTEM_FEATURE, + .matches = has_nested_virt_support, + .sys_reg = SYS_ID_AA64MMFR2_EL1, + .sign = FTR_UNSIGNED, + .field_pos = ID_AA64MMFR2_EL1_NV_SHIFT, + .field_width = 4, + .min_field_value = ID_AA64MMFR2_EL1_NV_IMP, + }, { .capability = ARM64_HAS_32BIT_EL0_DO_NOT_USE, .type = ARM64_CPUCAP_SYSTEM_FEATURE, diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 9c5573bc4614..3fd8f37830f2 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -2310,6 +2310,11 @@ static int __init early_kvm_mode_cfg(char *arg) return 0; } + if (strcmp(arg, "nested") == 0 && !WARN_ON(!is_kernel_in_hyp_mode())) { + kvm_mode = KVM_MODE_NV; + return 0; + } + return -EINVAL; } early_param("kvm-arm.mode", early_kvm_mode_cfg); diff --git a/arch/arm64/tools/cpucaps b/arch/arm64/tools/cpucaps index dfeb2c51e257..1af77a3657f7 100644 --- a/arch/arm64/tools/cpucaps +++ b/arch/arm64/tools/cpucaps @@ -31,6 +31,7 @@ HAS_GENERIC_AUTH_IMP_DEF HAS_IRQ_PRIO_MASKING HAS_LDAPR HAS_LSE_ATOMICS +HAS_NESTED_VIRT HAS_NO_FPSIMD HAS_NO_HW_PREFETCH HAS_PAN