From mboxrd@z Thu Jan  1 00:00:00 1970
From: Radim =?utf-8?B?S3LEjW3DocWZ?= <rkrcmar@redhat.com>
Subject: Re: [PATCH kvm-unit-tests] vmx: fixes for MAXPHYADDR requirement
Date: Thu, 25 Jan 2018 16:11:32 +0100
Message-ID: <20180125151132.GB19884@flask>
References: <1516212225-37393-2-git-send-email-pbonzini@redhat.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Cc: kvm@vger.kernel.org
To: Paolo Bonzini <pbonzini@redhat.com>
Return-path: <kvm-owner@vger.kernel.org>
Received: from mx1.redhat.com ([209.132.183.28]:39540 "EHLO mx1.redhat.com"
        rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
        id S1751374AbeAYPLl (ORCPT <rfc822;kvm@vger.kernel.org>);
        Thu, 25 Jan 2018 10:11:41 -0500
Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14])
        (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits))
        (No client certificate requested)
        by mx1.redhat.com (Postfix) with ESMTPS id 5E03E78232
        for <kvm@vger.kernel.org>; Thu, 25 Jan 2018 15:11:41 +0000 (UTC)
Content-Disposition: inline
In-Reply-To: <1516212225-37393-2-git-send-email-pbonzini@redhat.com>
Sender: kvm-owner@vger.kernel.org
List-ID: <kvm.vger.kernel.org>

2018-01-17 19:03+0100, Paolo Bonzini:
> The EPT access tests require at least 41 bits of guest physical address
> space.  This is because the test data needs a separate PML4 entry in the
> EPT table.  However, many consumer-grade processors have only 36 or
> 39-bit MAXPHYADDR, and the tests fail there with a page fault due to
> reserved bits set in the guest (GVA->GPA) page tables.
> 
> Add a test on MAXPHYADDR and skip the tests if they cannot run on the
> system under test, and only require 40 bits to lower the requirements.
> 
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  x86/vmx_tests.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/x86/vmx_tests.c b/x86/vmx_tests.c
> index e8c97f2..0c3b5a7 100644
> --- a/x86/vmx_tests.c
> +++ b/x86/vmx_tests.c
> @@ -2609,6 +2609,10 @@ static void ept_access_test_setup(void)
>  	if (setup_ept(false))
>  		test_skip("EPT not supported");
>  
> +	/* We use data->gpa = 1 << 39 so that test data has a separate pml4 entry */
> +	if (cpuid_maxphyaddr() < 40)

This does not help at the moment -- QEMU reports 40 even on hosts that
don't have as much.  It is a QEMU bug, so applied still, thanks.