From nobody Thu Dec 18 20:36:29 2025 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 7B10970830; Wed, 12 Feb 2025 01:43:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=13.77.154.182 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739324606; cv=none; b=LH9F5yYjWTEacyqKEK97AQ9AlrZsoOL2wK+wAElv9RgzZjnas/pDvg3zYdvgNSgtVOrDw5MtKNjUxwuFZbYMtn7xJvoyfhtkx6Q5HFdzMiwNU5XTzzDAXaT1UX/9wNnbomAdowSGoPLPJpi/lQzTVktMDushZYT+A/8mc4sppSA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739324606; c=relaxed/simple; bh=DXxR4o7FdA/wM/d2xFuE/K8y5g6RoVwgzCVwcakdFzM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=rGgajz1j9/aO25YMsM0KsXGyj4twgPEkeR9eDRBTns08BlHK9nGDSMhUtKuCABkD14xQ2cBMkAwVA6ph1dr1Ekc8vaOjzD3JwON2z/27erb95XeMo1LktS3+YOY87Uk12AzPgVrBcwcQAHouOtGIV5jIPNuDoTz4ZySEMrdmP2A= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com; spf=pass smtp.mailfrom=linux.microsoft.com; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b=HBSEQ717; arc=none smtp.client-ip=13.77.154.182 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="HBSEQ717" Received: from romank-3650.corp.microsoft.com (unknown [131.107.160.188]) by linux.microsoft.com (Postfix) with ESMTPSA id 7E4B22107AB7; Tue, 11 Feb 2025 17:43:23 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 7E4B22107AB7 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1739324603; bh=ke8cvJN/HfyiHGq5dWCetxLWOqUXILvWweb02I4ZK1c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=HBSEQ717Slt2XikuFXsv6EVMcSlkRpZmNGfZWorh0dzembs4fchjiNu946G6p0Pos NJEHBGxXxmJHGILF4w9YBh9Bc/mqdVs1wG8zfhiioyX0nYfyP+l2xWCwM3AF3DMOAd rIM8Kt2aVsfaBgHnF1RPL5yBOSEdHukKmafKctNA= 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, krzk+dt@kernel.org, kw@linux.com, kys@microsoft.com, lpieralisi@kernel.org, manivannan.sadhasivam@linaro.org, mingo@redhat.com, robh@kernel.org, ssengar@linux.microsoft.com, tglx@linutronix.de, wei.liu@kernel.org, will@kernel.org, devicetree@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: benhill@microsoft.com, bperkins@microsoft.com, sunilmut@microsoft.com Subject: [PATCH hyperv-next v4 1/6] arm64: hyperv: Use SMCCC to detect hypervisor presence Date: Tue, 11 Feb 2025 17:43:16 -0800 Message-ID: <20250212014321.1108840-2-romank@linux.microsoft.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20250212014321.1108840-1-romank@linux.microsoft.com> References: <20250212014321.1108840-1-romank@linux.microsoft.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" The arm64 Hyper-V startup path relies on ACPI to detect running under a Hyper-V compatible hypervisor. That doesn't work on non-ACPI systems. Hoist the ACPI detection logic into a separate function. Then use the vendor-specific hypervisor service call (implemented recently in Hyper-V) via SMCCC in the non-ACPI case. Signed-off-by: Roman Kisel --- arch/arm64/hyperv/mshyperv.c | 43 +++++++++++++++++++++++++++---- arch/arm64/include/asm/mshyperv.h | 5 ++++ 2 files changed, 43 insertions(+), 5 deletions(-) diff --git a/arch/arm64/hyperv/mshyperv.c b/arch/arm64/hyperv/mshyperv.c index fc49949b7df6..fe6185bf3bf2 100644 --- a/arch/arm64/hyperv/mshyperv.c +++ b/arch/arm64/hyperv/mshyperv.c @@ -27,6 +27,36 @@ int hv_get_hypervisor_version(union hv_hypervisor_versio= n_info *info) return 0; } =20 +static bool hyperv_detect_via_acpi(void) +{ + if (acpi_disabled) + return false; +#if IS_ENABLED(CONFIG_ACPI) + /* Hypervisor ID is only available in ACPI v6+. */ + if (acpi_gbl_FADT.header.revision < 6) + return false; + return strncmp((char *)&acpi_gbl_FADT.hypervisor_id, "MsHyperV", 8) =3D= =3D 0; +#else + return false; +#endif +} + +static bool hyperv_detect_via_smccc(void) +{ + struct arm_smccc_res res =3D {}; + + if (arm_smccc_1_1_get_conduit() !=3D SMCCC_CONDUIT_HVC) + return false; + arm_smccc_1_1_hvc(ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID, &res); + if (res.a0 =3D=3D SMCCC_RET_NOT_SUPPORTED) + return false; + + return res.a0 =3D=3D ARM_SMCCC_VENDOR_HYP_UID_HYPERV_REG_0 && + res.a1 =3D=3D ARM_SMCCC_VENDOR_HYP_UID_HYPERV_REG_1 && + res.a2 =3D=3D ARM_SMCCC_VENDOR_HYP_UID_HYPERV_REG_2 && + res.a3 =3D=3D ARM_SMCCC_VENDOR_HYP_UID_HYPERV_REG_3; +} + static int __init hyperv_init(void) { struct hv_get_vp_registers_output result; @@ -35,13 +65,11 @@ static int __init hyperv_init(void) =20 /* * Allow for a kernel built with CONFIG_HYPERV to be running in - * a non-Hyper-V environment, including on DT instead of ACPI. + * a non-Hyper-V environment. + * * In such cases, do nothing and return success. */ - if (acpi_disabled) - return 0; - - if (strncmp((char *)&acpi_gbl_FADT.hypervisor_id, "MsHyperV", 8)) + if (!hyperv_detect_via_acpi() && !hyperv_detect_via_smccc()) return 0; =20 /* Setup the guest ID */ @@ -72,6 +100,11 @@ static int __init hyperv_init(void) return ret; } =20 + ms_hyperv.vtl =3D get_vtl(); + /* Report if non-default VTL */ + if (ms_hyperv.vtl > 0) + pr_info("Linux runs in Hyper-V Virtual Trust Level\n"); + ms_hyperv_late_init(); =20 hyperv_initialized =3D true; diff --git a/arch/arm64/include/asm/mshyperv.h b/arch/arm64/include/asm/msh= yperv.h index 2e2f83bafcfb..a6d7eb9e167b 100644 --- a/arch/arm64/include/asm/mshyperv.h +++ b/arch/arm64/include/asm/mshyperv.h @@ -50,4 +50,9 @@ static inline u64 hv_get_msr(unsigned int reg) =20 #include =20 +#define ARM_SMCCC_VENDOR_HYP_UID_HYPERV_REG_0 0x4d32ba58U +#define ARM_SMCCC_VENDOR_HYP_UID_HYPERV_REG_1 0xcd244764U +#define ARM_SMCCC_VENDOR_HYP_UID_HYPERV_REG_2 0x8eef6c75U +#define ARM_SMCCC_VENDOR_HYP_UID_HYPERV_REG_3 0x16597024U + #endif --=20 2.43.0