From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by smtp.subspace.kernel.org (Postfix) with ESMTP id D603C3EA7B; Wed, 15 May 2024 17:33:52 +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=1715794434; cv=none; b=G7EM+/367FMRXjvJRNpE8YGWlvpRJRta3z+FufFNsTnnmK9SBV/R8iokpZdFAvlJ0MAjrcqlbisMyo1JKZxnny4xAkamfKTi/OmcdjPus2/CT04kTyjs2cfrZAt7hD0LoLYATSgbtg6Z+Vq2DXu4WxzVE3EZMQv3QxUSFEc47h0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715794434; c=relaxed/simple; bh=VdtVLFpZYA4b3uZzQCUTGVxEaXrt+6asF5DBt0OQKLQ=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=e6400zXRHfiTZoZSC5xHdgV9OdltxWFNBNECK/RuaN/dRINmxDJJKJ2TQ2ma7fk1AuBpPm4Cdar9BBQfLPZSEaDp/B9Ek8ZUSdNOrs4spddbX4FpKi4d2BJvZycXpRln9Ith/Xo8/3w0XDARPChh0pd9c/xlSgmS2qFC94Pwmb4= 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=EplThCPg; 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="EplThCPg" Received: from [10.137.186.190] (unknown [131.107.159.62]) by linux.microsoft.com (Postfix) with ESMTPSA id 60AFD20BE570; Wed, 15 May 2024 10:33:46 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 60AFD20BE570 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1715794426; bh=6znshs1azYcVfLPlekdOCordB4FAVfBn0O3niN9s+zc=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=EplThCPgxf2K/F8p5LTNBB2FpK+/bTpXukCuYhXyOYYlCqRIQfd1AiYryJzcSEWgl do+VYONXpz2SmVJUnMOFCJEWS/WmfZ+cUgYk3Rc9B+4zraitQvTQHirrfupbFHpAS6 qeNcZTp64f+P2tdvuN9exTKusSQCv8GS8E4jKlCM= Message-ID: <267ef0e2-2384-44bd-81f9-f33dda7bb9d2@linux.microsoft.com> Date: Wed, 15 May 2024 10:33:46 -0700 Precedence: bulk X-Mailing-List: linux-arch@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 1/6] arm64/hyperv: Support DeviceTree To: Krzysztof Kozlowski , arnd@arndb.de, bhelgaas@google.com, bp@alien8.de, catalin.marinas@arm.com, dave.hansen@linux.intel.com, decui@microsoft.com, haiyangz@microsoft.com, hpa@zytor.com, kw@linux.com, kys@microsoft.com, lenb@kernel.org, lpieralisi@kernel.org, mingo@redhat.com, mhklinux@outlook.com, rafael@kernel.org, robh@kernel.org, tglx@linutronix.de, wei.liu@kernel.org, will@kernel.org, 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: ssengar@microsoft.com, sunilmut@microsoft.com, vdso@hexbites.dev References: <20240514224508.212318-1-romank@linux.microsoft.com> <20240514224508.212318-2-romank@linux.microsoft.com> <1766fc9a-1d10-4c93-a9db-a7e0db8b01e7@linaro.org> Content-Language: en-US From: Roman Kisel In-Reply-To: <1766fc9a-1d10-4c93-a9db-a7e0db8b01e7@linaro.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 5/15/2024 12:45 AM, Krzysztof Kozlowski wrote: > On 15/05/2024 00:43, Roman Kisel wrote: >> The Virtual Trust Level platforms rely on DeviceTree, and the >> arm64/hyperv code supports ACPI only. Update the logic to >> support DeviceTree on boot as well as ACPI. >> >> Signed-off-by: Roman Kisel >> --- >> arch/arm64/hyperv/mshyperv.c | 34 +++++++++++++++++++++++++++++----- >> 1 file changed, 29 insertions(+), 5 deletions(-) >> >> diff --git a/arch/arm64/hyperv/mshyperv.c b/arch/arm64/hyperv/mshyperv.c >> index b1a4de4eee29..208a3bcb9686 100644 >> --- a/arch/arm64/hyperv/mshyperv.c >> +++ b/arch/arm64/hyperv/mshyperv.c >> @@ -15,6 +15,9 @@ >> #include >> #include >> #include >> +#include >> +#include >> +#include >> #include >> >> static bool hyperv_initialized; >> @@ -27,6 +30,29 @@ int hv_get_hypervisor_version(union hv_hypervisor_version_info *info) >> return 0; >> } >> >> +static bool hyperv_detect_fdt(void) >> +{ >> +#ifdef CONFIG_OF >> + const unsigned long hyp_node = of_get_flat_dt_subnode_by_name( >> + of_get_flat_dt_root(), "hypervisor"); > > Why do you add an ABI for node name? Although name looks OK, but is it > really described in the spec that you depend on it? I really do not like > name dependencies... Followed the existing DeviceTree's of naming and approaches in the kernel to surprise less and "invent" even less. As for the spec, the Hyper-V TLFS'es part discussing Hypervisor Discovery talks about x86 (https://learn.microsoft.com/en-us/virtualization/hyper-v-on-windows/tlfs/feature-discovery) only and via the ISA-provided means only. For arm64, Hyper-V code discovers the hypervisor presence via ACPI. Felt only natural to do the same for DeviceTree and arm64. > > Where is the binding for this? > Have not added, my mistake. Will place under Documentation/devicetree/bindings/bus/microsoft,hyperv.yaml > Best regards, > Krzysztof -- Thank you, Roman