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 AE1CF19E985; Thu, 19 Dec 2024 19:23:40 +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=1734636222; cv=none; b=pEjYD+CUH0gQ+Q8JFXm3QnE3GKoQJPhsqMmWVei5Srmu/ze4bB2SjIvOahWdu7Ev3U25Ql9hT32BjkfK9GU18mkTwPFf1+qY6/JTdwJAh4t6FBMX5ptw6ioxABjjQhluQrte/mP5EeBl1O/ga2sA4aWJMdHa7kud9EsRaAin9gI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734636222; c=relaxed/simple; bh=ZtLH46A3QbFZSSmlZAv/DybtCujBl+meUFbISoEdwEA=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=E1j1SsljqzE/rM0Y/rORQ17h0R8NSb7CU3CZUha/3KLqdCzHEVgvBixyV+TU2zMLvI2LVKlxZJtqHvw5lvQmBHi5A9iin5uVcc2lHHIRw/3w710bG8douQ6PIQbB6gVVJ07iVAUNEkJ9C1BwChRMTbAT5ej1MmWhLpuWGT4uSVU= 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=kemgBn3g; 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="kemgBn3g" Received: from [10.0.0.115] (c-67-182-156-199.hsd1.wa.comcast.net [67.182.156.199]) by linux.microsoft.com (Postfix) with ESMTPSA id E003C203FC92; Thu, 19 Dec 2024 11:23:39 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com E003C203FC92 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1734636220; bh=W8jaleRT5bUHjtz/TMEaivJ5xBVoEl/VqGOuKa+pKwU=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=kemgBn3g1jXQvQwCl5QagtYld/DVotR+dMvZU5NhIoE+rQiuyvdrVYfBM1n/ltfef +PPDAB6UOSAE0cwWfzgf9S7S7CBrvNFzWoeyNpAS4iHJkcP89AA5Sc++wVfJSkWEHN Y8X+UEyUxgG7sQOwhGReFnlEEJfKxLOvLczLA3MU= Message-ID: Date: Thu, 19 Dec 2024 11:23:39 -0800 Precedence: bulk X-Mailing-List: linux-hyperv@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/2] hyperv: Fix pointer type for the output of the hypercall in get_vtl(void) To: Easwar Hariharan Cc: Roman Kisel , hpa@zytor.com, kys@microsoft.com, bp@alien8.de, dave.hansen@linux.intel.com, decui@microsoft.com, haiyangz@microsoft.com, mingo@redhat.com, mhklinux@outlook.com, tglx@linutronix.de, tiala@microsoft.com, wei.liu@kernel.org, linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org, x86@kernel.org, apais@microsoft.com, benhill@microsoft.com, ssengar@microsoft.com, sunilmut@microsoft.com, vdso@hexbites.dev References: <20241218205421.319969-1-romank@linux.microsoft.com> <20241218205421.319969-2-romank@linux.microsoft.com> <17f81f98-a7ca-45e0-87be-9f1cfa5c5a95@linux.microsoft.com> <48d3a3e0-8e2f-4eb8-b725-b6eed37c290c@linux.microsoft.com> Content-Language: en-US From: Nuno Das Neves In-Reply-To: <48d3a3e0-8e2f-4eb8-b725-b6eed37c290c@linux.microsoft.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 12/19/2024 11:13 AM, Easwar Hariharan wrote: > On 12/19/2024 10:40 AM, Nuno Das Neves wrote: >> On 12/18/2024 12:54 PM, Roman Kisel wrote: >>> Commit bc905fa8b633 ("hyperv: Switch from hyperv-tlfs.h to hyperv/hvhdk.h") >>> changed the type of the output pointer to `struct hv_register_assoc` from >>> `struct hv_get_vp_registers_output`. That leads to an incorrect computation, >>> and leaves the system broken. >>> >> My bad! But, lets not use `struct hv_get_registers_output`. Instead, use >> `struct hv_register_value`, since that is the more complete definition of a >> register value. The output of the get_vp_registers hypercall is just an array >> of these values. >> >> Ideally we remove `struct hv_get_vp_registers_output` at some point, since >> it serves the same role as `struct hv_register_value` but in a more limited >> capacity. >> >> Thanks >> Nuno >> > > I had much the same conversation with Roman off-list yesterday. > > The choice is between using hv_get_registers_output which is clearly the > output of the GetVpRegisters hypercall by name, albeit limited as you If it's desirable to have a more 'friendly' naming here, then I'd be okay with: ``` /* NOTE: Linux helper struct - NOT from Hyper-V code */ struct hv_output_get_vp_registers { DECLARE_FLEX_ARRAY(struct hv_register_value, values); } ``` Note also the name is prefixed with "hv_output_" to match other hypercall outputs. > said, and hv_register_value which is the more complete definition and > what the hypervisor actually returns, but does not currently include the > arm64 definitions in our copy of hvgdk_mini.h. hv_get_registers_output > and hv_register_value overlap in layout for Roman's purposes. > > FWIW, I'm in favor of adding the arm64 definitions to hv_register_value > and using it for this get_vtl() patch. > > This could be accompanied with migration of hv_get_vpreg128 in arm64/ > and removal of struct hv_get_registers_output, or that could be deferred > to a later patch. I'd be happy to submit a followup patch to update the arm64 code to use hv_register_value, or a new struct as outlined above. It is a pretty small change though, it might be easier to just include it in this series. Nuno > > - Easwar