From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-hyperv-owner@vger.kernel.org>
X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on
	aws-us-west-2-korg-lkml-1.web.codeaurora.org
Received: from vger.kernel.org (vger.kernel.org [23.128.96.18])
	by smtp.lore.kernel.org (Postfix) with ESMTP id DA922C77B73
	for <linux-hyperv@archiver.kernel.org>; Fri, 26 May 2023 16:49:21 +0000 (UTC)
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S236964AbjEZQtV (ORCPT <rfc822;linux-hyperv@archiver.kernel.org>);
        Fri, 26 May 2023 12:49:21 -0400
Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48412 "EHLO
        lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S237139AbjEZQtU (ORCPT
        <rfc822;linux-hyperv@vger.kernel.org>);
        Fri, 26 May 2023 12:49:20 -0400
Received: from smtp-1908.mail.infomaniak.ch (smtp-1908.mail.infomaniak.ch [IPv6:2001:1600:4:17::1908])
        by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5D96FD9
        for <linux-hyperv@vger.kernel.org>; Fri, 26 May 2023 09:49:19 -0700 (PDT)
Received: from smtp-2-0001.mail.infomaniak.ch (unknown [10.5.36.108])
        by smtp-3-3000.mail.infomaniak.ch (Postfix) with ESMTPS id 4QSW9963HFzMqBk5;
        Fri, 26 May 2023 18:49:17 +0200 (CEST)
Received: from unknown by smtp-2-0001.mail.infomaniak.ch (Postfix) with ESMTPA id 4QSW954GcnzMpq7x;
        Fri, 26 May 2023 18:49:13 +0200 (CEST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=digikod.net;
        s=20191114; t=1685119757;
        bh=aghhZZz/jAHNei4obfycQdpoNYo23x/hMTO/WYvr+D4=;
        h=Date:Subject:To:Cc:References:From:In-Reply-To:From;
        b=aNpuEEhr3qfgoQBoABl/c/Soy37k/dWbg29l53qY084NrLE1aBB96NeIw1GJ+t33V
         pd9trvFbpyUukW/iVPpk0eBX/Jwsza/CoS5PoumlcDlW/vnInB0QV0Wjo7cpI7eeQk
         00f3/lqql1UIb9Yq02grk2akHYn3y+PAXnI212IM=
Message-ID: <7671b432-569a-d176-315b-d5f66fe205ef@digikod.net>
Date:   Fri, 26 May 2023 18:49:12 +0200
MIME-Version: 1.0
User-Agent: 
Subject: Re: [PATCH v1 6/9] KVM: x86: Add Heki hypervisor support
Content-Language: en-US
To:     Wei Liu <wei.liu@kernel.org>
Cc:     Borislav Petkov <bp@alien8.de>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        "H . Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
        Kees Cook <keescook@chromium.org>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Sean Christopherson <seanjc@google.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Vitaly Kuznetsov <vkuznets@redhat.com>,
        Wanpeng Li <wanpengli@tencent.com>,
        Alexander Graf <graf@amazon.com>,
        Forrest Yuan Yu <yuanyu@google.com>,
        James Morris <jamorris@linux.microsoft.com>,
        John Andersen <john.s.andersen@intel.com>,
        Liran Alon <liran.alon@oracle.com>,
        "Madhavan T . Venkataraman" <madvenka@linux.microsoft.com>,
        Marian Rotariu <marian.c.rotariu@gmail.com>,
        =?UTF-8?Q?Mihai_Don=c8=9bu?= <mdontu@bitdefender.com>,
        =?UTF-8?B?TmljdciZb3IgQ8OuyJt1?= <nicu.citu@icloud.com>,
        Rick Edgecombe <rick.p.edgecombe@intel.com>,
        Thara Gopinath <tgopinath@microsoft.com>,
        Will Deacon <will@kernel.org>,
        Zahra Tarkhani <ztarkhani@microsoft.com>,
        =?UTF-8?Q?=c8=98tefan_=c8=98icleru?= <ssicleru@bitdefender.com>,
        dev@lists.cloudhypervisor.org, kvm@vger.kernel.org,
        linux-hardening@vger.kernel.org, linux-hyperv@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        linux-security-module@vger.kernel.org, qemu-devel@nongnu.org,
        virtualization@lists.linux-foundation.org, x86@kernel.org,
        xen-devel@lists.xenproject.org
References: <20230505152046.6575-1-mic@digikod.net>
 <20230505152046.6575-7-mic@digikod.net>
 <ZFlnJRsJh2fX3IJb@liuwe-devbox-debian-v2>
From:   =?UTF-8?Q?Micka=c3=abl_Sala=c3=bcn?= <mic@digikod.net>
In-Reply-To: <ZFlnJRsJh2fX3IJb@liuwe-devbox-debian-v2>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit
X-Infomaniak-Routing: alpha
Precedence: bulk
List-ID: <linux-hyperv.vger.kernel.org>
X-Mailing-List: linux-hyperv@vger.kernel.org


On 08/05/2023 23:18, Wei Liu wrote:
> On Fri, May 05, 2023 at 05:20:43PM +0200, Mickaël Salaün wrote:
>> From: Madhavan T. Venkataraman <madvenka@linux.microsoft.com>
>>
>> Each supported hypervisor in x86 implements a struct x86_hyper_init to
>> define the init functions for the hypervisor.  Define a new init_heki()
>> entry point in struct x86_hyper_init.  Hypervisors that support Heki
>> must define this init_heki() function.  Call init_heki() of the chosen
>> hypervisor in init_hypervisor_platform().
>>
>> Create a heki_hypervisor structure that each hypervisor can fill
>> with its data and functions. This will allow the Heki feature to work
>> in a hypervisor agnostic way.
>>
>> Declare and initialize a "heki_hypervisor" structure for KVM so KVM can
>> support Heki.  Define the init_heki() function for KVM.  In init_heki(),
>> set the hypervisor field in the generic "heki" structure to the KVM
>> "heki_hypervisor".  After this point, generic Heki code can access the
>> KVM Heki data and functions.
>>
> [...]
>> +static void kvm_init_heki(void)
>> +{
>> +	long err;
>> +
>> +	if (!kvm_para_available())
>> +		/* Cannot make KVM hypercalls. */
>> +		return;
>> +
>> +	err = kvm_hypercall3(KVM_HC_LOCK_MEM_PAGE_RANGES, -1, -1, -1);
> 
> Why not do a proper version check or capability check here? If the ABI
> or supported features ever change then we have something to rely on?

The attributes will indeed get extended, but I wanted to have a simple 
proposal for now.

Do you mean to get the version of this hypercall e.g., with a dedicated 
flag, like with the 
landlock_create_ruleset/LANDLOCK_CREATE_RULESET_VERSION syscall?


> 
> Thanks,
> Wei.