From: Dan Williams <dan.j.williams@intel.com>
To: "Huang, Kai" <kai.huang@intel.com>,
"Williams, Dan J" <dan.j.williams@intel.com>,
"Hansen, Dave" <dave.hansen@intel.com>,
"seanjc@google.com" <seanjc@google.com>
Cc: "Lindgren, Tony" <tony.lindgren@intel.com>,
"Edgecombe, Rick P" <rick.p.edgecombe@intel.com>,
"binbin.wu@linux.intel.com" <binbin.wu@linux.intel.com>,
"Chatre, Reinette" <reinette.chatre@intel.com>,
"Li, Xiaoyao" <xiaoyao.li@intel.com>,
"Zhao, Yan Y" <yan.y.zhao@intel.com>,
"Hunter, Adrian" <adrian.hunter@intel.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"pbonzini@redhat.com" <pbonzini@redhat.com>,
"Yamahata, Isaku" <isaku.yamahata@intel.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"kristen@linux.intel.com" <kristen@linux.intel.com>
Subject: Re: [PATCH 3/3] KVM: VMX: Initialize TDX during KVM module load
Date: Thu, 31 Oct 2024 14:52:32 -0700 [thread overview]
Message-ID: <6723fc2070a96_60c3294dc@dwillia2-mobl3.amr.corp.intel.com.notmuch> (raw)
In-Reply-To: <46ea74bcd8eebe241a143e9280c65ca33cb8dcce.camel@intel.com>
Huang, Kai wrote:
> On Wed, 2024-10-30 at 08:19 -0700, Sean Christopherson wrote:
> > On Tue, Oct 29, 2024, Kai Huang wrote:
> > > diff --git a/arch/x86/kvm/Makefile b/arch/x86/kvm/Makefile
> > > index f9dddb8cb466..fec803aff7ad 100644
> > > --- a/arch/x86/kvm/Makefile
> > > +++ b/arch/x86/kvm/Makefile
> > > @@ -20,6 +20,7 @@ kvm-intel-y += vmx/vmx.o vmx/vmenter.o vmx/pmu_intel.o vmx/vmcs12.o \
> > >
> > > kvm-intel-$(CONFIG_X86_SGX_KVM) += vmx/sgx.o
> > > kvm-intel-$(CONFIG_KVM_HYPERV) += vmx/hyperv.o vmx/hyperv_evmcs.o
> > > +kvm-intel-$(CONFIG_INTEL_TDX_HOST) += vmx/tdx.o
> >
> > IMO, INTEL_TDX_HOST should be a KVM Kconfig, e.g. KVM_INTEL_TDX. Forcing the user
> > to bounce between KVM's menu and the generic menu to enable KVM support for TDX is
> > kludgy. Having INTEL_TDX_HOST exist before KVM support came along made sense, as
> > it allowed compile-testing a bunch of code, but I don't think it should be the end
> > state.
> >
> > If others disagree, then we should adjust KVM_AMD_SEV in the opposite direction,
> > because doing different things for SEV vs. TDX is confusing and messy.
>
> + Dave (and Dan for TDX Connect).
>
> Agree SEV/TDX should be in similar way. But also I find SEV has a dependency on
> CRYPTO_DEV_SP_PSP, so perhaps it also reasonable to make an additional
> KVM_INTEL_TDX and make it depend on INTEL_TDX_HOST?
>
> We could remove INTEL_TDX_HOST but only keep KVM_INTEL_TDX. But in the long
> term, more kernel components will need to add TDX support (e.g., for TDX
> Connect). I think the question is whether we can safely disable TDX code in ALL
> kernel components when KVM_INTEL_TDX is not enabled.
>
> If the answer is yes (seems correct to me, because it seems meaningless to
> enable TDX code in _ANY_ kernel components when it's even possible to run TDX
> guest), then I think we can just change the current INTEL_TDX_HOST to
> KVM_INTEL_TDX and put it in arch/x86/kvm/Kconfig.
I agree with Sean's later reply that kvm-intel.ko should fail if
anything that is expected to be there and not otherwise permanently
disabled fails setup.
However, I want to provide a counterpoint to this "_ANY_ kernel
component" dependency on being able to run a TDX guest. TDX Connect like
SEV-TIO offers device-security provisioning flows that are expected to
run before any confidential guest is being launched, and theoretically
may offer services independent of *ever* launching a guest (e.g. PCIe
link encrcyption without device assignment). So longer term, seamcalls
without kvm-intel.ko flexibility is useful, but in the near term a
coarse dependency on kvm-intel.ko is workable.
next prev parent reply other threads:[~2024-10-31 21:52 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-10-28 13:20 [PATCH 0/3] KVM: VMX: Initialize TDX when loading KVM module Kai Huang
2024-10-28 13:20 ` [PATCH 1/3] KVM: VMX: Refactor VMX module init/exit functions Kai Huang
2024-10-28 13:20 ` [PATCH 2/3] KVM: Export hardware virtualization enabling/disabling functions Kai Huang
2024-10-28 13:20 ` [PATCH 3/3] KVM: VMX: Initialize TDX during KVM module load Kai Huang
2024-10-30 15:19 ` Sean Christopherson
2024-10-31 11:17 ` Huang, Kai
2024-10-31 20:22 ` Sean Christopherson
2024-10-31 21:21 ` Huang, Kai
2024-10-31 21:29 ` Edgecombe, Rick P
2024-11-06 14:19 ` Edgecombe, Rick P
2024-11-06 10:49 ` Huang, Kai
2024-11-06 15:01 ` Sean Christopherson
2024-11-06 20:06 ` Huang, Kai
2024-11-07 22:04 ` Sean Christopherson
2024-11-07 23:25 ` Huang, Kai
2024-10-31 21:52 ` Dan Williams [this message]
2024-10-31 22:37 ` Huang, Kai
2024-10-31 22:56 ` Dan Williams
2024-10-28 17:41 ` [PATCH 0/3] KVM: VMX: Initialize TDX when loading KVM module Paolo Bonzini
-- strict thread matches above, loose matches on Subject: below --
2024-11-27 20:10 [PATCH v3 0/3] KVM: VMX: Initialize TDX during KVM module load Paolo Bonzini
2024-11-27 20:10 ` [PATCH 3/3] " Paolo Bonzini
2024-11-28 3:00 ` Chao Gao
2024-11-28 3:04 ` Huang, Kai
2024-11-28 3:34 ` Huang, Kai
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