From patchwork Sat Mar 15 00:19:21 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roman Kisel X-Patchwork-Id: 14017636 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 56A7DC282EC for ; Sat, 15 Mar 2025 00:24:52 +0000 (UTC) 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-Owner; bh=aql5r+qoxxmeaa5n+o0/Ssl6ac0GgBlAhM7f7Q3glr8=; b=t3Zl/XuQ9lQcwtrQFXckQIts1J P+qAhpcbye5I5BluDXcGDny9WHnu48gLofATjbO0UKBJ9IsGzKdzCiiF/pbRMnMHy7XyGurQa61pe n/Um7AVh7hlVb8B3IfDItANscWbGIx/aCdmgUPSg5/W0ztQnsdM5nAKaQoqxeumrUeoQ4UsVks8cT WfOUU01Hu8cvifw7+A5LfwFZ22EMnkobbQwPrE35lR6axmzKyNzPm4q2jGLcbrPqqmYaSUUi1pgNN 9CwvXwTt5TvcEQuAA9T3BspxDyJld9HUn1HrVbm25I1JPFEVThzwjzMMNwiv8+1lmgFmMywBlOeNR 5XCSldWw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1ttFKW-0000000Faop-1mOQ; Sat, 15 Mar 2025 00:24:44 +0000 Received: from linux.microsoft.com ([13.77.154.182]) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1ttFFW-0000000FZQT-40cU for linux-arm-kernel@lists.infradead.org; Sat, 15 Mar 2025 00:19:37 +0000 Received: from romank-3650.corp.microsoft.com (unknown [131.107.160.188]) by linux.microsoft.com (Postfix) with ESMTPSA id 42809203345B; Fri, 14 Mar 2025 17:19:33 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 42809203345B DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1741997973; bh=aql5r+qoxxmeaa5n+o0/Ssl6ac0GgBlAhM7f7Q3glr8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Uz81xrgO/miBAtyqNCUSuH+fm3WMwxzvu4Vc2poacr5p/Ae/6bkQ3EXgmuENFjJJP 6jZdGqez7yKNEwKkpS/iEuYOwpAKEQodmdYZP9DDVddGr4fVmnzgbv37xd8KxGMgpe yGL5PcDmxcU6D9PAte4nmAEp8Ms+c05KH1A4erKk= From: Roman Kisel To: arnd@arndb.de, bhelgaas@google.com, bp@alien8.de, catalin.marinas@arm.com, conor+dt@kernel.org, dan.carpenter@linaro.org, dave.hansen@linux.intel.com, decui@microsoft.com, haiyangz@microsoft.com, hpa@zytor.com, joey.gouly@arm.com, krzk+dt@kernel.org, kw@linux.com, kys@microsoft.com, lenb@kernel.org, lpieralisi@kernel.org, manivannan.sadhasivam@linaro.org, mark.rutland@arm.com, maz@kernel.org, mingo@redhat.com, oliver.upton@linux.dev, rafael@kernel.org, robh@kernel.org, ssengar@linux.microsoft.com, sudeep.holla@arm.com, suzuki.poulose@arm.com, tglx@linutronix.de, wei.liu@kernel.org, will@kernel.org, yuzenghui@huawei.com, devicetree@vger.kernel.org, kvmarm@lists.linux.dev, linux-acpi@vger.kernel.org, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, x86@kernel.org Cc: apais@microsoft.com, benhill@microsoft.com, bperkins@microsoft.com, sunilmut@microsoft.com Subject: [PATCH hyperv-next v6 01/11] arm64: kvm, smccc: Introduce and use API for detecting hypervisor presence Date: Fri, 14 Mar 2025 17:19:21 -0700 Message-ID: <20250315001931.631210-2-romank@linux.microsoft.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20250315001931.631210-1-romank@linux.microsoft.com> References: <20250315001931.631210-1-romank@linux.microsoft.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250314_171935_037629_59826CDB X-CRM114-Status: GOOD ( 15.05 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org The KVM/arm64 uses SMCCC to detect hypervisor presence. That code is private, and it follows the SMCCC specification. Other existing and emerging hypervisor guest implementations can and should use that standard approach as well. Factor out a common infrastructure that the guests can use, update KVM to employ the new API. The central notion of the SMCCC method is the UUID of the hypervisor, and the API follows that. No functional changes. Validated with a KVM/arm64 guest. Signed-off-by: Roman Kisel Acked-by: Arnd Bergmann --- arch/arm64/kvm/hypercalls.c | 5 +-- drivers/firmware/smccc/kvm_guest.c | 10 ++---- drivers/firmware/smccc/smccc.c | 19 +++++++++++ include/linux/arm-smccc.h | 55 +++++++++++++++++++++++++++--- 4 files changed, 73 insertions(+), 16 deletions(-) diff --git a/arch/arm64/kvm/hypercalls.c b/arch/arm64/kvm/hypercalls.c index 27ce4cb44904..92b9bc1ea8e8 100644 --- a/arch/arm64/kvm/hypercalls.c +++ b/arch/arm64/kvm/hypercalls.c @@ -353,10 +353,7 @@ int kvm_smccc_call_handler(struct kvm_vcpu *vcpu) val[0] = gpa; break; case ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID: - val[0] = ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_0; - val[1] = ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_1; - val[2] = ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_2; - val[3] = ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_3; + UUID_TO_SMCCC_RES(ARM_SMCCC_VENDOR_HYP_UID_KVM, val); break; case ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID: val[0] = smccc_feat->vendor_hyp_bmap; diff --git a/drivers/firmware/smccc/kvm_guest.c b/drivers/firmware/smccc/kvm_guest.c index f3319be20b36..b5084b309ea0 100644 --- a/drivers/firmware/smccc/kvm_guest.c +++ b/drivers/firmware/smccc/kvm_guest.c @@ -14,17 +14,11 @@ static DECLARE_BITMAP(__kvm_arm_hyp_services, ARM_SMCCC_KVM_NUM_FUNCS) __ro_afte void __init kvm_init_hyp_services(void) { + uuid_t kvm_uuid = ARM_SMCCC_VENDOR_HYP_UID_KVM; struct arm_smccc_res res; u32 val[4]; - if (arm_smccc_1_1_get_conduit() != SMCCC_CONDUIT_HVC) - return; - - arm_smccc_1_1_invoke(ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID, &res); - if (res.a0 != ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_0 || - res.a1 != ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_1 || - res.a2 != ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_2 || - res.a3 != ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_3) + if (!arm_smccc_hyp_present(&kvm_uuid)) return; memset(&res, 0, sizeof(res)); diff --git a/drivers/firmware/smccc/smccc.c b/drivers/firmware/smccc/smccc.c index a74600d9f2d7..7399f27d58e5 100644 --- a/drivers/firmware/smccc/smccc.c +++ b/drivers/firmware/smccc/smccc.c @@ -67,6 +67,25 @@ s32 arm_smccc_get_soc_id_revision(void) } EXPORT_SYMBOL_GPL(arm_smccc_get_soc_id_revision); +bool arm_smccc_hyp_present(const uuid_t *hyp_uuid) +{ + struct arm_smccc_res res = {}; + + if (arm_smccc_1_1_get_conduit() != SMCCC_CONDUIT_HVC) + return false; + arm_smccc_1_1_hvc(ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID, &res); + if (res.a0 == SMCCC_RET_NOT_SUPPORTED) + return false; + + return ({ + const uuid_t uuid = SMCCC_RES_TO_UUID(res.a0, res.a1, res.a2, res.a3); + const bool present = uuid_equal(&uuid, hyp_uuid); + + present; + }); +} +EXPORT_SYMBOL_GPL(arm_smccc_hyp_present); + static int __init smccc_devices_init(void) { struct platform_device *pdev; diff --git a/include/linux/arm-smccc.h b/include/linux/arm-smccc.h index 67f6fdf2e7cd..726f18221f1c 100644 --- a/include/linux/arm-smccc.h +++ b/include/linux/arm-smccc.h @@ -7,6 +7,11 @@ #include #include + +#ifndef __ASSEMBLER__ +#include +#endif + #include /* @@ -107,10 +112,10 @@ ARM_SMCCC_FUNC_QUERY_CALL_UID) /* KVM UID value: 28b46fb6-2ec5-11e9-a9ca-4b564d003a74 */ -#define ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_0 0xb66fb428U -#define ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_1 0xe911c52eU -#define ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_2 0x564bcaa9U -#define ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_3 0x743a004dU +#define ARM_SMCCC_VENDOR_HYP_UID_KVM UUID_INIT(\ + 0xb66fb428, 0xc52e, 0xe911, \ + 0xa9, 0xca, 0x4b, 0x56, \ + 0x4d, 0x00, 0x3a, 0x74) /* KVM "vendor specific" services */ #define ARM_SMCCC_KVM_FUNC_FEATURES 0 @@ -333,6 +338,48 @@ s32 arm_smccc_get_soc_id_version(void); */ s32 arm_smccc_get_soc_id_revision(void); +#ifndef __ASSEMBLER__ + +/** + * arm_smccc_hyp_present(const uuid_t *hyp_uuid) + * + * Returns `true` if the hypervisor advertises its presence via SMCCC. + * + * When the function returns `false`, the caller shall not assume that + * there is no hypervisor running. Instead, the caller must fall back to + * other approaches if any are available. + */ +bool arm_smccc_hyp_present(const uuid_t *hyp_uuid); + +#define SMCCC_RES_TO_UUID(r0, r1, r2, r3) \ + UUID_INIT( \ + cpu_to_le32(lower_32_bits(r0)), \ + cpu_to_le32(lower_32_bits(r1)) & 0xffff, \ + cpu_to_le32(lower_32_bits(r1)) >> 16, \ + cpu_to_le32(lower_32_bits(r2)) & 0xff, \ + (cpu_to_le32(lower_32_bits(r2)) >> 8) & 0xff, \ + (cpu_to_le32(lower_32_bits(r2)) >> 16) & 0xff, \ + (cpu_to_le32(lower_32_bits(r2)) >> 24) & 0xff, \ + cpu_to_le32(lower_32_bits(r3)) & 0xff, \ + (cpu_to_le32(lower_32_bits(r3)) >> 8) & 0xff, \ + (cpu_to_le32(lower_32_bits(r3)) >> 16) & 0xff, \ + (cpu_to_le32(lower_32_bits(r3)) >> 24) & 0xff \ + ) + +#define UUID_TO_SMCCC_RES(uuid_init, regs) do { \ + const uuid_t uuid = uuid_init; \ + (regs)[0] = le32_to_cpu((u32)uuid.b[0] | (uuid.b[1] << 8) | \ + ((uuid.b[2]) << 16) | ((uuid.b[3]) << 24)); \ + (regs)[1] = le32_to_cpu((u32)uuid.b[4] | (uuid.b[5] << 8) | \ + ((uuid.b[6]) << 16) | ((uuid.b[7]) << 24)); \ + (regs)[2] = le32_to_cpu((u32)uuid.b[8] | (uuid.b[9] << 8) | \ + ((uuid.b[10]) << 16) | ((uuid.b[11]) << 24)); \ + (regs)[3] = le32_to_cpu((u32)uuid.b[12] | (uuid.b[13] << 8) | \ + ((uuid.b[14]) << 16) | ((uuid.b[15]) << 24)); \ + } while (0) + +#endif /* !__ASSEMBLER__ */ + /** * struct arm_smccc_res - Result from SMC/HVC call * @a0-a3 result values from registers 0 to 3