linux-kernel - Re: [RFC PATCH 1/3] kvm: x86: Rename KVM_DEBUGREG_RELOAD to KVM_DEBUGREG_NEED

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <8223a7e2-5d4a-b427-c44f-d76450f16748@redhat.com>
Date:   Sat, 25 Apr 2020 21:16:14 +0200
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Nadav Amit <nadav.amit@...il.com>
Cc:     Xiaoyao Li <xiaoyao.li@...el.com>,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        kvm <kvm@...r.kernel.org>, Nadav Amit <namit@...technion.ac.il>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        linux-kernel@...r.kernel.org
Subject: Re: [RFC PATCH 1/3] kvm: x86: Rename KVM_DEBUGREG_RELOAD to
 KVM_DEBUGREG_NEED_RELOAD

On 25/04/20 18:54, Nadav Amit wrote:
>> I wonder if KVM_DEBUGREG_RELOAD is needed at all.  It should be easy to
>> write selftests for it, using the testcase in commit message
>> 172b2386ed16 and the information in commit ae561edeb421.
> I must be missing something, since I did not follow this thread and other
> KVM changes very closely.
> 
> Yet, for the record, I added KVM_DEBUGREG_RELOAD due to real experienced
> issues that I had while running Intel’s fuzzing tests on KVM: IIRC, the DRs
> were not reloaded after an INIT event that clears them.

Indeed, but the code has changed since then and I'm not sure it is still
needed.

> Personally, I would prefer that a test for that, if added, would be added
> to KVM-unit-tests, based on Liran’s INIT test. This would allow to confirm
> bare-metal behaves as the VM.

Yes, that would be good as well of course.

Paolo