From nobody Wed Dec 17 06:02:15 2025 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 7C9961F3B8D; Mon, 14 Apr 2025 22:47:16 +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=1744670839; cv=none; b=slaL+xzODWO3vyHVsV0tM+KuCsLObn0oEugNRmLKY4gPGN8UqoxZbyFhT80q8wvvKQBfE/D4y4oRurQJNFT4/BPdttBbgtxkHwLj61TbuS7To0bitTVQB2xM6eaprSikTdQobDQfAsDO8dpK3cHW+D0rmsnLPbHrM/cqWs2el6M= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744670839; c=relaxed/simple; bh=qMdX+OYxCd+405CKynjk8lSsHu591NwkBTr5jpSPm0o=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=rOSlqskzG97cZRogaSy19XDIB8ePTw7mdZQWwYLUvUkJHwFAN/rN5WS+juLGA3jfVz43pSi1yKmSWVW3oWQmhy3Jk9+whG8ee8PlF7JXgnwR73mh3hfuCYvtKZirRPWIlQdVtB65H5ndKGbrjRCOu3gCpVOedNAuun+f1yfIrAs= 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=FOZ335NE; 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="FOZ335NE" Received: from romank-3650.corp.microsoft.com (unknown [131.107.159.188]) by linux.microsoft.com (Postfix) with ESMTPSA id 9D7CF210C42D; Mon, 14 Apr 2025 15:47:15 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 9D7CF210C42D DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1744670835; bh=NYi43WhtS1hVthbgtuaLVNWnlw3+yXhxoNWNK/Qb6Jg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FOZ335NEPx1NnMrhoMAyeAlWfWIw/LtKYiNBBk0X0NRof/x+k37UKIbRtvWAiV88R 6s6uqWrG6LuFFUR2ekZSO9z0fgE9DMa5B4gAwBqGAjVzP7mecGMmYJ1qjp12aZORE7 3tXtmvohB+dh4XBKgmZUN2qIFOilUz00BouvElAk= 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, rafael.j.wysocki@intel.com, 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 v8 02/11] arm64: hyperv: Use SMCCC to detect hypervisor presence Date: Mon, 14 Apr 2025 15:47:04 -0700 Message-ID: <20250414224713.1866095-3-romank@linux.microsoft.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20250414224713.1866095-1-romank@linux.microsoft.com> References: <20250414224713.1866095-1-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 | 50 ++++++++++++++++++++++++++++++++---- 1 file changed, 45 insertions(+), 5 deletions(-) diff --git a/arch/arm64/hyperv/mshyperv.c b/arch/arm64/hyperv/mshyperv.c index 4e27cc29c79e..21458b6338aa 100644 --- a/arch/arm64/hyperv/mshyperv.c +++ b/arch/arm64/hyperv/mshyperv.c @@ -28,6 +28,48 @@ int hv_get_hypervisor_version(union hv_hypervisor_versio= n_info *info) } EXPORT_SYMBOL_GPL(hv_get_hypervisor_version); =20 +#ifdef CONFIG_ACPI + +static bool __init hyperv_detect_via_acpi(void) +{ + if (acpi_disabled) + return false; + /* + * Hypervisor ID is only available in ACPI v6+, and the + * structure layout was extended in v6 to accommodate that + * new field. + * + * At the very minimum, this check makes sure not to read + * past the FADT structure. + * + * It is also needed to catch running in some unknown + * non-Hyper-V environment that has ACPI 5.x or less. + * In such a case, it can't be Hyper-V. + */ + if (acpi_gbl_FADT.header.revision < 6) + return false; + return strncmp((char *)&acpi_gbl_FADT.hypervisor_id, "MsHyperV", 8) =3D= =3D 0; +} + +#else + +static bool __init hyperv_detect_via_acpi(void) +{ + return false; +} + +#endif + +static bool __init hyperv_detect_via_smccc(void) +{ + uuid_t hyperv_uuid =3D UUID_INIT( + 0x58ba324d, 0x6447, 0x24cd, + 0x75, 0x6c, 0xef, 0x8e, + 0x24, 0x70, 0x59, 0x16); + + return arm_smccc_hypervisor_has_uuid(&hyperv_uuid); +} + static int __init hyperv_init(void) { struct hv_get_vp_registers_output result; @@ -36,13 +78,11 @@ 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 */ --=20 2.43.0