linux-kernel - Re: [PATCH v3 10/21] KVM:x86: Add #CP support in guest exception classification

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]

Date:   Fri, 16 Jun 2023 14:56:20 +0800
From:   "Yang, Weijiang" <weijiang.yang@...el.com>
To:     Sean Christopherson <seanjc@...gle.com>
CC:     Chao Gao <chao.gao@...el.com>, <pbonzini@...hat.com>,
        <kvm@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <peterz@...radead.org>, <rppt@...nel.org>,
        <binbin.wu@...ux.intel.com>, <rick.p.edgecombe@...el.com>,
        <john.allen@....com>
Subject: Re: [PATCH v3 10/21] KVM:x86: Add #CP support in guest exception
 classification


On 6/16/2023 7:58 AM, Sean Christopherson wrote:
> On Thu, Jun 08, 2023, Weijiang Yang wrote:
>> On 6/6/2023 5:08 PM, Chao Gao wrote:
>>> On Thu, May 11, 2023 at 12:08:46AM -0400, Yang Weijiang wrote:
>>>> Add handling for Control Protection (#CP) exceptions(vector 21).
>>>> The new vector is introduced for Intel's Control-Flow Enforcement
>>>> Technology (CET) relevant violation cases.
>>>>
>>>> Although #CP belongs contributory exception class, but the actual
>>>> effect is conditional on CET being exposed to guest. If CET is not
>>>> available to guest, #CP falls back to non-contributory and doesn't
>>>> have an error code.
>>> This sounds weird. is this the hardware behavior? If yes, could you
>>> point us to where this behavior is documented?
>> It's not SDM documented behavior.
> The #CP behavior needs to be documented.  Please pester whoever you need to in
> order to make that happen.

Do you mean documentation for #CP as an generic exception or the 
behavior in KVM as

this patch shows?