linux-kernel - Re: [PATCH v11 025/113] KVM: TDX: Use private memory for TDX

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: <9fa4473f76f20b94a8ba516defb3b33ac3e86e96.camel@intel.com>
Date:   Tue, 17 Jan 2023 22:52:35 +0000
From:   "Huang, Kai" <kai.huang@...el.com>
To:     "Christopherson,, Sean" <seanjc@...gle.com>
CC:     "dmatlack@...gle.com" <dmatlack@...gle.com>,
        "Shahar, Sagi" <sagis@...gle.com>,
        "chao.p.peng@...ux.intel.com" <chao.p.peng@...ux.intel.com>,
        "isaku.yamahata@...il.com" <isaku.yamahata@...il.com>,
        "Aktas, Erdem" <erdemaktas@...gle.com>,
        "kvm@...r.kernel.org" <kvm@...r.kernel.org>,
        "pbonzini@...hat.com" <pbonzini@...hat.com>,
        "Yamahata, Isaku" <isaku.yamahata@...el.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v11 025/113] KVM: TDX: Use private memory for TDX

On Tue, 2023-01-17 at 16:40 +0000, Sean Christopherson wrote:
> On Mon, Jan 16, 2023, Huang, Kai wrote:
> > On Thu, 2023-01-12 at 08:31 -0800, isaku.yamahata@...el.com wrote:
> > > From: Chao Peng <chao.p.peng@...ux.intel.com>
> > > 
> > > Override kvm_arch_has_private_mem() to use fd-based private memory.
> > > Return true when a VM has a type of KVM_X86_TDX_VM.
> > > 
> > > Signed-off-by: Chao Peng <chao.p.peng@...ux.intel.com>
> > > Signed-off-by: Isaku Yamahata <isaku.yamahata@...el.com>
> > > ---
> > >  arch/x86/kvm/x86.c | 5 +++++
> > >  1 file changed, 5 insertions(+)
> > > 
> > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> > > index d548d3af6428..a8b555935fd8 100644
> > > --- a/arch/x86/kvm/x86.c
> > > +++ b/arch/x86/kvm/x86.c
> > > @@ -13498,6 +13498,11 @@ int kvm_sev_es_string_io(struct kvm_vcpu *vcpu, unsigned int size,
> > >  }
> > >  EXPORT_SYMBOL_GPL(kvm_sev_es_string_io);
> > >  
> > > +bool kvm_arch_has_private_mem(struct kvm *kvm)
> > > +{
> > > +	return kvm->arch.vm_type == KVM_X86_TDX_VM;
> > > +}
> > > +
> > 
> > AMD's series has a different solution:
> > 
> > https://lore.kernel.org/lkml/20221214194056.161492-3-michael.roth@amd.com/
> > 
> > I think somehow this needs to get aligned.
> 
> Ya.  My thought is
> 
>  bool kvm_arch_has_private_mem(struct kvm *kvm)
>  {
> 	return kvm->arch.vm_type != KVM_X86_DEFAULT_VM;
>  }
> 
> where the VM types end up being:
> 
>  #define KVM_X86_DEFAULT_VM	0
>  #define KVM_X86_PROTECTED_VM	1
>  #define KVM_X86_TDX_VM		2
>  #define KVM_X86_SNP_VM		3

What's the  difference between  PROTECTED_VM vs TDX_VM/SNP_VM, may I ask?

> 
> Don't spend too much time reworking the TDX series at this point, I'm going to do
> a trial run of combining UPM+TDX+SNP sometime in the next few weeks to see how all
> the pieces fit together, this is one of the common touchpoints that I'll make sure
> to look at.  Though if you have ideas on, by all means post them.

Glad to know.  Thanks for your time.