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 76C701A4F2D; Thu, 19 Dec 2024 19:13:23 +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=1734635604; cv=none; b=aYQzjK+P1InmukaDTMogf6PGRxKgEpCFeF8LnJGZRQYSe4oNbOCYlyGHsvR9aNJTsUl4SdY5/An/RtWZ4AHJphGI+npkqsLvz+e897emfxQZCIU0B/vUYEp9TFebOw83nqg2Z9/OS2ElGUEijCWe5q76/4aJESHt2pjABrV+O9w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734635604; c=relaxed/simple; bh=Epvc05yZp+JriEP1qzC/ayKd+iOTtR7QXO0IJqVep6c=; h=Message-ID:Date:MIME-Version:Cc:Subject:To:References:From: In-Reply-To:Content-Type; b=LL4NwP1R70eNz3e4l4JIl1H4nHXS7xxrDn5jOSxgbs5BTZoE6qk8DL02Xsp7quW4Dz+Kmha6ICbgsPNfLIGBdCL14TxHZ+5mhgHtXyP1d6000QnJgAH8yNiwAhMkjaqT/q/I8nTSYjVJes5lvFkOwrHIvmmmURl6x1CVWKJCCfQ= 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=qALNb0if; 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="qALNb0if" Received: from [100.65.65.151] (unknown [20.236.10.206]) by linux.microsoft.com (Postfix) with ESMTPSA id 3787D203FC94; Thu, 19 Dec 2024 11:13:21 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 3787D203FC94 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1734635603; bh=Mba+4T/AX0gSvO32ObFAyK9BFdMDXvwhmVsHsmcIloc=; h=Date:Cc:Subject:To:References:From:In-Reply-To:From; b=qALNb0ifgemTV7U9ZxwYMHG3KZbI32kyISCenHQiESZSRgYKOBi1YYGhV7Wltwlrh X1VzAlDrcMuOOWTVVCQEv4g1WyTYNdB5jFDpuPhuef0/eGEVl3PnPVqq0+aZrhEz2u w4IStOKoOhOTK5xV6in/pToKRMv9KE0vGEXcDt+k= Message-ID: <48d3a3e0-8e2f-4eb8-b725-b6eed37c290c@linux.microsoft.com> Date: Thu, 19 Dec 2024 11:13:21 -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 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, eahariha@linux.microsoft.com, apais@microsoft.com, benhill@microsoft.com, ssengar@microsoft.com, sunilmut@microsoft.com, vdso@hexbites.dev Subject: Re: [PATCH 1/2] hyperv: Fix pointer type for the output of the hypercall in get_vtl(void) To: Nuno Das Neves References: <20241218205421.319969-1-romank@linux.microsoft.com> <20241218205421.319969-2-romank@linux.microsoft.com> <17f81f98-a7ca-45e0-87be-9f1cfa5c5a95@linux.microsoft.com> Content-Language: en-US From: Easwar Hariharan In-Reply-To: <17f81f98-a7ca-45e0-87be-9f1cfa5c5a95@linux.microsoft.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit 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 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. - Easwar