From patchwork Fri Mar 7 22:02:53 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roman Kisel X-Patchwork-Id: 14007228 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 B66DAC28B28 for ; Fri, 7 Mar 2025 22:04:57 +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=crNwfx5sWO6ZIXa2Lum/1YdoYksCdhY6yt/6b1xxBXk=; b=Zcanj2iyA7tFF124ySLvzloVsV Ib3xcVQODbKkhSyRNADUVwFWL9hbIglXVZOqZ9XEixl2ZNN2aovM/naAlI5VKrR+1vNSBUuuiKiTJ fuDATuF+Lc5g9xbyEx2mMOyO5BKDEDC/lEwdACtY+esFsJr8UBtllq2CBte+vCaAj6bz3HI7F+/Zt +j6aDhgplmrRGciaEyzcqazaYB2tNyghRqrvFyISSJendlDsZnfEMrzVJD9mZ9vslQCOHYHEQWEn0 ZWjEmPbsIY8w6LFeF+0kauJyPTZ6lNQsvRAHSc4sHwmvHZ8LNU7SfNkMp/+BZYYMVYieBazslWaSR VPh2go3w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tqfoG-0000000FeTf-2jte; Fri, 07 Mar 2025 22:04:48 +0000 Received: from linux.microsoft.com ([13.77.154.182]) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tqfmc-0000000Fdwt-3DZe for linux-arm-kernel@lists.infradead.org; Fri, 07 Mar 2025 22:03:07 +0000 Received: from romank-3650.corp.microsoft.com (unknown [131.107.160.188]) by linux.microsoft.com (Postfix) with ESMTPSA id DAA7F2038F3F; Fri, 7 Mar 2025 14:03:05 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com DAA7F2038F3F DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1741384986; bh=crNwfx5sWO6ZIXa2Lum/1YdoYksCdhY6yt/6b1xxBXk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nZ5yFEYJIPJImxKy1DRUB78Xk8Ut2RPpbRHd0uc8sWN8XnPaGdOfpD34LoGAUjpv5 E4q9/S4GbKtRuvqtjYQ5WWpgHKm3CbSk/qGqeHhWhEwas5b1HdJqpna9pmlT4lYeaq Z07UJbO/rV0sMmIof4u9PpYcVdXsy//s6ZApgbnI= From: Roman Kisel To: arnd@arndb.de, bhelgaas@google.com, bp@alien8.de, catalin.marinas@arm.com, conor+dt@kernel.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 v5 01/11] arm64: kvm, smccc: Introduce and use API for detectting hypervisor presence Date: Fri, 7 Mar 2025 14:02:53 -0800 Message-ID: <20250307220304.247725-2-romank@linux.microsoft.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20250307220304.247725-1-romank@linux.microsoft.com> References: <20250307220304.247725-1-romank@linux.microsoft.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250307_140306_850708_1EC01C95 X-CRM114-Status: GOOD ( 15.07 ) 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 cenrtal 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