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 for Android: free password hash cracker in your pocket

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

Message-ID: <ZIulniryqlj0hLnt@google.com>
Date:   Thu, 15 Jun 2023 16:58:22 -0700
From:   Sean Christopherson <seanjc@...gle.com>
To:     Weijiang Yang <weijiang.yang@...el.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 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.