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: 14007235 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 E3D5FC28B2E for ; Fri, 7 Mar 2025 22:08:14 +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=x2+6YzGCH9kvF8OEuWUHwwZtKWajMltLjCzPTk0Dvcs=; b=Ew2XM3Q281eEyZzT9CvXgehFmI igxdfVeYb0YqjGrfA0nKNhRjSZtpBBqZbDSca3Vp+wC4G6TD/Ntx/mjhdg8RYYnPIwNzxqBS5MrNf FM0ODwb3+HrGrCXNTRiUbV6huQmM2zL7pjWAvwb9wvqs7PUC6EJuLWgXV+QTMabexE0MlN1KZ8DE7 zuuFyFGEc3kzSsRmS0gLRouYWr9FlAae89Te4YfM04r2kryEx9eBq7DkqPhu2INcr94qClTfwgQKb 6M58QjexxB653FJARKPOxmwhh7XOtl7SXxuF2/IMhkoHRg2OYsOh34/GvZjkST3f+gcoFD/LmcKQS wHYUJkow==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tqfrT-0000000FfJP-0VSl; Fri, 07 Mar 2025 22:08:07 +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-0000000FdxK-44zD for linux-arm-kernel@lists.infradead.org; Fri, 07 Mar 2025 22:03:08 +0000 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> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250307_140307_094306_120060C9 X-CRM114-Status: GOOD ( 15.60 ) 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 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 */