From patchwork Fri Mar 7 22:02:54 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roman Kisel X-Patchwork-Id: 871301 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by smtp.subspace.kernel.org (Postfix) with ESMTP id DEE531A5B88; Fri, 7 Mar 2025 22:03:06 +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=1741384988; cv=none; b=RMR5iWKRUWqsHZ6SiWZFo393nF2d+1crzHuoU2Nyo5LWUFYA9y7eYgYnOCo3i+9rxLDVGNNXzIgGVqW1yx5mJyIk2J4rk6XITkAhfz0OS2cODfVpiUpxuVfk8OTP2WIttcczTo79YRhxZ11/8NnI0U69EHzG2T6nEUELMvxc/OM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741384988; c=relaxed/simple; bh=DXZcwdqZ7+Um99Yu8bVX4q33teL2kYIRtuPMN8W1wxU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=KT7g8RNAoPRIq+F9f5w/KFGM9hUCE72wVosBCpNtH3cvA394nYw5C+v81ou8yD1q/+zDmAcb2IyWZA7G8PNlWJHTdBvbvZQfalR3TnFpLziV0h9aj5/HyidSt+4al+wjwxLw+tnEkqeERcEBfPTDUDvP9QS3tPn6GGJ6Wxwn6j4= 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=In1feEoe; 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="In1feEoe" Received: from romank-3650.corp.microsoft.com (unknown [131.107.160.188]) by linux.microsoft.com (Postfix) with ESMTPSA id 437382038F41; Fri, 7 Mar 2025 14:03:06 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 437382038F41 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1741384986; bh=x2+6YzGCH9kvF8OEuWUHwwZtKWajMltLjCzPTk0Dvcs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=In1feEoej6g5R7YwZKrifZ7XSySTtbdcPhNwaBQT5494/M+viSKmvOWWNrrNvQ/Oz xNuxOm3d0XjQT+vyIU0IFIgfV3vHUxLsfWAki95awHyrPmpsE30jQoPkJE117JU+C7 ii1Hw0jDB8CvmyB6mMfoA6GPskf6aNzT23flev+Q= 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 02/11] arm64: hyperv: Use SMCCC to detect hypervisor presence Date: Fri, 7 Mar 2025 14:02:54 -0800 Message-ID: <20250307220304.247725-3-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> Precedence: bulk X-Mailing-List: linux-acpi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 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 +++++++++++++++++++++++++++++++----- 1 file changed, 38 insertions(+), 5 deletions(-) diff --git a/arch/arm64/hyperv/mshyperv.c b/arch/arm64/hyperv/mshyperv.c index 29fcfd595f48..c647db56fd6b 100644 --- a/arch/arm64/hyperv/mshyperv.c +++ b/arch/arm64/hyperv/mshyperv.c @@ -27,6 +27,41 @@ int hv_get_hypervisor_version(union hv_hypervisor_version_info *info) return 0; } +static bool __init hyperv_detect_via_acpi(void) +{ + if (acpi_disabled) + return false; +#if IS_ENABLED(CONFIG_ACPI) + /* + * 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) == 0; +#else + return false; +#endif +} + +static bool __init hyperv_detect_via_smccc(void) +{ + uuid_t hyperv_uuid = UUID_INIT( + 0x4d32ba58, 0x4764, 0xcd24, + 0x75, 0x6c, 0xef, 0x8e, + 0x24, 0x70, 0x59, 0x16); + + return arm_smccc_hyp_present(&hyperv_uuid); +} + static int __init hyperv_init(void) { struct hv_get_vp_registers_output result; @@ -35,13 +70,11 @@ static int __init hyperv_init(void) /* * 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; /* Setup the guest ID */