linux-kernel - Re: [PATCH 0/4] Add support for XMM fast hypercalls

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 for Android: free password hash cracker in your pocket

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

Message-ID: <033e7d77-d640-2c12-4918-da6b5b7f4e21@redhat.com>
Date:   Thu, 8 Apr 2021 17:30:26 +0200
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Wei Liu <wei.liu@...nel.org>,
        Siddharth Chandrasekaran <sidcha@...zon.de>
Cc:     kys@...rosoft.com, haiyangz@...rosoft.com, sthemmin@...rosoft.com,
        tglx@...utronix.de, mingo@...hat.com, bp@...en8.de, x86@...nel.org,
        hpa@...or.com, seanjc@...gle.com, vkuznets@...hat.com,
        wanpengli@...cent.com, jmattson@...gle.com, joro@...tes.org,
        graf@...zon.com, eyakovl@...zon.de, linux-hyperv@...r.kernel.org,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Subject: Re: [PATCH 0/4] Add support for XMM fast hypercalls

On 08/04/21 17:28, Wei Liu wrote:
>> Although the Hyper-v TLFS mentions that a guest cannot use this feature
>> unless the hypervisor advertises support for it, some hypercalls which
>> we plan on upstreaming in future uses them anyway.
>
> No, please don't do this. Check the feature bit(s) before you issue
> hypercalls which rely on the extended interface.

Perhaps Siddharth should clarify this, but I read it as Hyper-V being 
buggy and using XMM arguments unconditionally.

Paolo